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Groups > sci.electronics.design > #451909 > unrolled thread
| Started by | "billbowden" <bperryb@bowdenshobbycircuits.info> |
|---|---|
| First post | 2017-03-14 20:18 -0800 |
| Last post | 2017-03-24 21:35 +0200 |
| Articles | 20 on this page of 301 — 34 participants |
Back to article view | Back to sci.electronics.design
Antenna ferrite loopsticks verses air core? "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-03-14 20:18 -0800
Re: Antenna ferrite loopsticks verses air core? John Robertson <spam@flippers.com> - 2017-03-14 22:21 -0700
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-14 23:43 -0700
Re: Antenna ferrite loopsticks verses air core? "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-03-15 12:27 -0800
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-15 17:19 -0700
Re: Antenna ferrite loopsticks verses air core? "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-03-15 18:51 -0800
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-15 20:08 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-16 00:24 -0400
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-15 22:17 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-16 13:04 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-15 02:48 -0400
Re: Antenna ferrite loopsticks verses air core? makolber@yahoo.com - 2017-03-15 06:35 -0700
Re: Antenna ferrite loopsticks verses air core? "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-03-15 12:46 -0800
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-15 17:22 -0700
Re: Antenna ferrite loopsticks verses air core? Mike Perkins <spam@spam.com> - 2017-03-30 01:42 +0100
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-29 18:20 -0700
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-16 08:44 +0200
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-16 00:17 -0700
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-17 00:58 +0200
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-16 16:19 -0700
Re: Antenna ferrite loopsticks verses air core? "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-03-15 13:01 -0800
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-15 17:39 -0400
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-15 17:33 -0700
Re: Antenna ferrite loopsticks verses air core? "Dave M" <dgminala@mediacombb.net> - 2017-03-15 09:40 -0500
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-15 17:26 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-15 08:25 -0700
Re: Antenna ferrite loopsticks verses air core? Tim Wescott <seemywebsite@myfooter.really> - 2017-03-15 12:38 -0500
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-15 17:28 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-15 17:59 -0700
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-15 18:10 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-16 08:20 -0700
Re: Antenna ferrite loopsticks verses air core? George Herold <gherold@teachspin.com> - 2017-03-16 09:45 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-16 10:26 -0700
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-16 15:47 -0700
Re: Antenna ferrite loopsticks verses air core? George Herold <gherold@teachspin.com> - 2017-03-16 17:15 -0700
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-16 17:36 -0700
Re: Antenna ferrite loopsticks verses air core? George Herold <gherold@teachspin.com> - 2017-03-16 18:46 -0700
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-16 23:45 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-17 07:30 -0700
Re: Antenna ferrite loopsticks verses air core? George Herold <gherold@teachspin.com> - 2017-03-17 08:28 -0700
Re: Antenna ferrite loopsticks verses air core? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-17 11:38 -0400
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-17 12:21 -0700
Re: Antenna ferrite loopsticks verses air core? "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-03-17 13:08 -0800
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-18 10:32 +1100
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-17 17:10 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-17 22:31 -0400
Re: Antenna ferrite loopsticks verses air core? pcdhobbs@gmail.com - 2017-03-18 14:53 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-18 20:38 -0400
Re: Antenna ferrite loopsticks verses air core? Jeff Liebermann <jeffl@cruzio.com> - 2017-03-18 18:10 -0700
Re: Antenna ferrite loopsticks verses air core? pcdhobbs@gmail.com - 2017-03-18 18:39 -0700
Re: Antenna ferrite loopsticks verses air core? Jeff Liebermann <jeffl@cruzio.com> - 2017-03-19 09:53 -0700
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-19 12:27 +1100
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-18 22:11 -0400
Re: Antenna ferrite loopsticks verses air core? "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-19 10:41 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-17 17:13 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-17 17:28 -0700
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-18 12:21 +0200
Re: Antenna ferrite loopsticks verses air core? Allan Herriman <allanherriman@hotmail.com> - 2017-03-18 12:15 +0000
Re: Antenna ferrite loopsticks verses air core? George Herold <gherold@teachspin.com> - 2017-03-17 17:36 -0700
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-17 18:09 -0700
Re: Antenna ferrite loopsticks verses air core? George Herold <gherold@teachspin.com> - 2017-03-17 18:21 -0700
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-18 10:49 +0200
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-18 08:30 -0700
Re: Antenna ferrite loopsticks verses air core? mkolber1@gmail.com - 2017-03-18 12:49 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-18 12:57 -0700
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-18 23:48 +0200
Re: Antenna ferrite loopsticks verses air core? krw@notreal.com - 2017-03-18 20:08 -0400
Re: Antenna ferrite loopsticks verses air core? kevin93 <kevin@whitedigs.com> - 2017-03-18 13:09 -0700
Re: Antenna ferrite loopsticks verses air core? "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-18 04:08 -0500
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-19 12:32 +1100
Re: Antenna ferrite loopsticks verses air core? "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-19 10:45 -0500
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-20 11:08 +1100
Re: Antenna ferrite loopsticks verses air core? "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-19 22:31 -0500
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-20 16:31 +1100
Re: Antenna ferrite loopsticks verses air core? "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-21 01:19 -0500
Re: Antenna ferrite loopsticks verses air core? Jasen Betts <jasen@xnet.co.nz> - 2017-03-22 19:15 +0000
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-18 10:41 +1100
Re: Antenna ferrite loopsticks verses air core? pcdhobbs@gmail.com - 2017-03-18 14:47 -0700
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-19 00:22 +0200
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-19 12:39 +1100
Re: Antenna ferrite loopsticks verses air core? pcdhobbs@gmail.com - 2017-03-18 19:11 -0700
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-19 13:15 +1100
Re: Antenna ferrite loopsticks verses air core? pcdhobbs@gmail.com - 2017-03-20 04:26 -0700
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-21 13:17 +1100
Re: Antenna ferrite loopsticks verses air core? "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-21 01:32 -0500
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-21 10:38 +0200
Re: Antenna ferrite loopsticks verses air core? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-21 02:53 -0400
Re: Antenna ferrite loopsticks verses air core? pcdhobbs@gmail.com - 2017-03-21 01:01 -0700
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-21 12:33 +0200
Re: Antenna ferrite loopsticks verses air core? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-21 09:42 -0400
Re: Antenna ferrite loopsticks verses air core? piglet <erichpwagner@hotmail.com> - 2017-03-21 19:05 +0000
Re: Antenna ferrite loopsticks verses air core? George Herold <gherold@teachspin.com> - 2017-03-21 12:49 -0700
Re: Antenna ferrite loopsticks verses air core? piglet <erichpwagner@hotmail.com> - 2017-03-21 18:39 +0000
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-21 22:39 +0200
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-21 12:30 +0200
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-19 17:43 +0200
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-21 14:39 +0200
Re: Antenna ferrite loopsticks verses air core? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-21 09:46 -0400
Re: Antenna ferrite loopsticks verses air core? George Herold <gherold@teachspin.com> - 2017-03-17 17:31 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-17 17:46 -0700
Re: Antenna ferrite loopsticks verses air core? George Herold <gherold@teachspin.com> - 2017-03-17 18:18 -0700
Re: Antenna ferrite loopsticks verses air core? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-21 09:55 -0400
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-17 07:27 -0700
Re: Antenna ferrite loopsticks verses air core? DemonicTubes <tlackie@gmail.com> - 2017-03-17 09:11 -0700
Re: Antenna ferrite loopsticks verses air core? pcdhobbs@gmail.com - 2017-03-17 11:40 -0700
Re: Antenna ferrite loopsticks verses air core? bitrex <bitrex@de.lete.earthlink.net> - 2017-03-17 12:29 -0400
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-17 12:25 -0700
Re: Antenna ferrite loopsticks verses air core? bitrex <bitrex@de.lete.earthlink.net> - 2017-03-18 16:20 -0400
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-16 15:41 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-16 16:14 -0700
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-16 16:25 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-19 11:22 -0500
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-15 21:20 -0500
Re: Antenna ferrite loopsticks verses air core? "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-15 23:02 -0500
Re: Antenna ferrite loopsticks verses air core? whit3rd <whit3rd@gmail.com> - 2017-03-15 22:52 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-16 02:48 -0400
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-16 00:10 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-16 08:21 -0500
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-16 16:10 -0700
Re: Antenna ferrite loopsticks verses air core? Bill Beaty <billb@eskimo.com> - 2017-03-16 12:12 -0700
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-16 13:06 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-16 15:39 -0500
Re: Antenna ferrite loopsticks verses air core? John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-16 19:57 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-18 21:26 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-17 09:44 -0700
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-17 17:35 -0700
Re: Antenna ferrite loopsticks verses air core? "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-03-17 18:35 -0800
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-20 09:01 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-19 08:20 -0500
Re: Antenna ferrite loopsticks verses air core? "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-03-19 15:31 -0800
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-19 19:42 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-19 19:20 -0500
Re: Antenna ferrite loopsticks verses air core? Phil Allison <pallison49@gmail.com> - 2017-03-19 17:49 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-19 20:19 -0500
Re: Antenna ferrite loopsticks verses air core? Robert Baer <robertbaer@localnet.com> - 2017-03-19 19:44 -0800
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-20 00:00 -0400
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-19 23:56 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 08:36 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-20 09:29 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 12:54 -0500
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 13:16 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-20 12:31 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-20 16:46 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 17:17 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-20 18:25 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 17:15 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-20 18:25 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 17:56 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-20 18:49 -0700
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-21 00:19 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-21 07:27 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-21 07:28 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-21 11:24 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-21 13:39 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-23 13:52 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-23 16:48 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-23 23:58 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-24 01:13 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-24 07:00 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-24 12:47 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-24 15:13 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-24 17:05 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-24 08:44 -0500
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-24 09:13 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-24 09:40 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-24 13:08 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-24 13:42 -0700
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-24 14:20 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-24 22:46 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-24 22:13 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-25 09:29 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-25 11:33 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 15:20 -0400
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-25 15:25 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 19:17 -0400
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-25 17:02 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 21:25 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-25 20:10 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 21:32 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-25 22:42 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-26 00:00 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-26 04:00 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-26 05:36 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-26 09:34 -0500
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-26 10:23 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-26 13:10 -0400
Re: Antenna ferrite loopsticks verses air core? Jasen Betts <jasen@xnet.co.nz> - 2017-03-27 09:32 +0000
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-25 14:44 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 16:34 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-25 16:12 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 17:44 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-25 17:08 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-25 16:00 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-25 18:27 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 19:31 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-25 21:21 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 23:42 -0400
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-25 17:34 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-20 16:34 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 17:21 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-20 18:27 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 17:54 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-20 20:55 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 20:09 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-20 21:28 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 21:23 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-20 23:25 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-21 07:54 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-21 07:57 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-21 11:54 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-21 12:21 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-21 21:40 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-21 13:27 -0400
Re: Antenna ferrite loopsticks verses air core? "billbowden" <bperryb@bowdenshobbycircuits.info> - 2017-03-20 15:41 -0800
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-20 19:13 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-20 21:18 -0400
Re: Antenna ferrite loopsticks verses air core? "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-21 04:35 -0500
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-20 11:06 +0200
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-24 10:14 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-24 13:59 -0400
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-24 13:36 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 13:49 -0400
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-25 12:30 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-25 21:39 -0400
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-26 07:35 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-26 13:15 -0400
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-27 07:46 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-27 10:59 -0400
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-27 09:22 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-27 23:47 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-28 18:15 +1100
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-28 03:42 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-28 19:07 +1100
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-28 04:35 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-28 21:58 +1100
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-28 09:42 -0500
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-28 12:51 +0300
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-28 07:23 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-29 13:28 -0400
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-30 00:37 +0300
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-29 21:02 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-28 09:57 -0500
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-28 09:05 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-28 11:27 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-29 13:29 -0400
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-27 14:57 +0300
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-27 07:25 -0500
Re: Antenna ferrite loopsticks verses air core? Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-03-27 09:47 -0700
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-27 19:51 +0300
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-27 12:21 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-27 18:54 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-28 10:16 +1100
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-27 16:58 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-27 23:33 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-28 18:18 +1100
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-28 03:48 -0400
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-28 07:28 -0700
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-28 13:41 +0300
Re: Antenna ferrite loopsticks verses air core? Jasen Betts <jasen@xnet.co.nz> - 2017-03-28 07:44 +0000
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-27 21:18 -0500
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-28 18:22 +1100
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-28 04:01 -0400
Re: Antenna ferrite loopsticks verses air core? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-28 11:04 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-28 10:58 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-28 11:13 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-28 10:12 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-29 13:47 -0400
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-29 14:18 -0500
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-30 00:47 +0300
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-29 19:15 -0500
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-29 21:40 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-29 14:26 +1100
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-29 23:47 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-29 10:18 +1100
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-03-29 19:12 -0500
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-29 11:49 +1100
Re: Antenna ferrite loopsticks verses air core? Jeff Liebermann <jeffl@cruzio.com> - 2017-03-29 18:21 -0700
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-29 14:19 +1100
Re: Antenna ferrite loopsticks verses air core? Jeff Liebermann <jeffl@cruzio.com> - 2017-03-29 18:01 -0700
Re: Antenna ferrite loopsticks verses air core? Ralph Barone <ralph@invalid.com> - 2017-03-30 02:35 +0000
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-03-29 14:23 +1100
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-29 23:46 -0400
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-03-30 21:40 -0700
Re: Antenna ferrite loopsticks verses air core? krw@notreal.com - 2017-03-31 20:08 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-04-02 12:59 +1000
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-04-01 23:55 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-04-02 14:36 +1000
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-04-02 01:56 -0400
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-04-02 18:11 +1000
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-04-02 07:35 -0500
Re: Antenna ferrite loopsticks verses air core? mkolber1@gmail.com - 2017-04-02 06:16 -0700
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-04-03 07:40 +1000
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-04-02 08:12 -0700
Re: Antenna ferrite loopsticks verses air core? Clifford Heath <no.spam@please.net> - 2017-04-03 08:47 +1000
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-04-02 18:39 -0700
Re: Antenna ferrite loopsticks verses air core? amdx <nojunk@knology.net> - 2017-04-02 21:22 -0500
Re: Antenna ferrite loopsticks verses air core? dagmargoodboat@yahoo.com - 2017-04-03 14:12 -0700
Re: Antenna ferrite loopsticks verses air core? rickman <gnuarm@gmail.com> - 2017-03-27 23:25 -0400
Re: Antenna ferrite loopsticks verses air core? upsidedown@downunder.com - 2017-03-28 12:58 +0300
Re: Antenna ferrite loopsticks verses air core? Joerg <news@analogconsultants.com> - 2017-03-27 07:52 -0700
Re: Antenna ferrite loopsticks verses air core? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-24 21:35 +0200
Page 15 of 16 — ← Prev page 1 … 13 14 [15] 16 Next page →
| From | Clifford Heath <no.spam@please.net> |
|---|---|
| Date | 2017-03-29 14:23 +1100 |
| Message-ID | <58dc75d2$0$15579$c3e8da3$9deca2c3@news.astraweb.com> |
| In reply to | #454165 |
On 30/03/17 12:01, Jeff Liebermann wrote: > On Wed, 29 Mar 2017 10:18:33 +1100, Clifford Heath > <no.spam@please.net> wrote: > >> Why worry about increasing Q above 500, when you can get more >> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >> more antenna wire? > > Because the added 3 inches will add equal amounts of signal and noise, > resulting in no net improvement. It's always fun to drag things to > their logical extreme. Instead of 3 inches, add 3 miles of wire. The > recovered energy will be huge and possibly sufficient to draw an arc. > But, so will the received atmospheric noise be huge by the same > amount. Besides less loss, a higher Q also means more selectivity, so > the receiver won't act the like the first crystal set I built in > middle skool, which received and demodulated most of the AM broadcast > band simultaneously. There's an upper limit to Q as set by the > modulation bandwidth. The AM broadcast band runs about 10KHz per > channel, so the maximum usable loaded Q would be: > Q = 1,000 KHz / 10 KHz = 100 > Any Q more than 100 at BCB frequencies will begin dropping the higher > audio frequencies from the modulation. Too narrow band, and all you > can hear will be CW (Morse Code). There's also the problem of tuning > stability, where anything that causes the high Q coil to drift in > frequency, will produce even harmonic distortion of the audio. Copper > wire is not particularly temperature stable and will require some form > of frequency or tuning stabilization. > > Ok, back to taxes... If you aren't going to read the thread for context, then just stick with your taxes. We're talking about increasing Q above where it starts to exclude some of the signal frequencies. Of course there is also noise excluded in that process, but that's unlikely to improve SNR.
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-03-29 23:46 -0400 |
| Message-ID | <obhutr$4ul$1@dont-email.me> |
| In reply to | #454184 |
On 3/28/2017 11:23 PM, Clifford Heath wrote: > On 30/03/17 12:01, Jeff Liebermann wrote: >> On Wed, 29 Mar 2017 10:18:33 +1100, Clifford Heath >> <no.spam@please.net> wrote: >> >>> Why worry about increasing Q above 500, when you can get more >>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >>> more antenna wire? >> >> Because the added 3 inches will add equal amounts of signal and noise, >> resulting in no net improvement. It's always fun to drag things to >> their logical extreme. Instead of 3 inches, add 3 miles of wire. The >> recovered energy will be huge and possibly sufficient to draw an arc. >> But, so will the received atmospheric noise be huge by the same >> amount. Besides less loss, a higher Q also means more selectivity, so >> the receiver won't act the like the first crystal set I built in >> middle skool, which received and demodulated most of the AM broadcast >> band simultaneously. There's an upper limit to Q as set by the >> modulation bandwidth. The AM broadcast band runs about 10KHz per >> channel, so the maximum usable loaded Q would be: >> Q = 1,000 KHz / 10 KHz = 100 >> Any Q more than 100 at BCB frequencies will begin dropping the higher >> audio frequencies from the modulation. Too narrow band, and all you >> can hear will be CW (Morse Code). There's also the problem of tuning >> stability, where anything that causes the high Q coil to drift in >> frequency, will produce even harmonic distortion of the audio. Copper >> wire is not particularly temperature stable and will require some form >> of frequency or tuning stabilization. >> >> Ok, back to taxes... > > If you aren't going to read the thread for context, then just stick with > your taxes. > > We're talking about increasing Q above where it starts to exclude > some of the signal frequencies. Of course there is also noise > excluded in that process, but that's unlikely to improve SNR. Please follow your own advice. You and Joerg are the only posters here who are saying the high Q of the coil will impact the bandwidth. We have patiently explained to you that the Q of the receiver will *NOT* be as high as the Q of the antenna and will not adversely impact the bandwidth of the received signal. -- Rick C
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| From | dagmargoodboat@yahoo.com |
|---|---|
| Date | 2017-03-30 21:40 -0700 |
| Message-ID | <38f6e8e9-b9ea-46e7-9169-bed65a02906e@googlegroups.com> |
| In reply to | #454152 |
On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote: > On 29/03/17 02:12, amdx wrote: > > On 3/28/2017 2:22 AM, Clifford Heath wrote: > >> On 28/03/17 13:18, amdx wrote: > >>> On 3/27/2017 6:16 PM, Clifford Heath wrote: > >>>> On 27/03/17 23:25, amdx wrote: > >>>>> On 3/27/2017 6:57 AM, Tauno Voipio wrote: > >>>>>> Joerg, you seem not understand the innermost sense of the crystal- > >>>>>> radio people. They are closely related to audiophools, and it is > >>>>>> quite impossible to use sensible technical argumentation here. > >>>>> > >>>>> I don't get that at all, can you back that up with any facts? > >>>> > >>>> ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? > >>> > >>> You haven't connected an antenna, and tried to drive a headset yet. > >> > >> Umm, I think that was me in about 1971. > > > >> > >>>> More voltage does not create better audio. > >>> > >>> But if it is a very weak signal on the antenna, you don't want to > >>> waste any signal in loss resistances. > >> > >> You start to *reject* some of the received power as soon as the > >> Q passes 200ish, and you destroy the audio at the same time. > >> > >> You can quadruple your received power by doubling your coil > >> diameter, or fitting a longer wire. That's *far* FAR more > >> effective than saving 0.2% by using higher Q. > > > > Crystal radios do not use the coil to collect RF energy from the air, > > a long wire antenna of 25ft to 150 is attached tothe coil to pickup the > > RF signal. > > If you want to discuss loop antennas, start a new thread. > > > > > >> With a crystal ear-piece, you still may have an impedance matching > >> problem. For that, you should use an audio transformer *after* > >> the detector. > >> > >> Sorry to puncture your dogma. > > > > Take a breath! > > I'll start simple, Coil and tuning cap have a unloaded Q of > > 1000. To extract maximum power you use a load that matches the > > Q times Xl of the coil. Loading the coil with it's matched > > impedance lowers the Q to 500. > > You're making slightly more sense than Rickman, who hasn't > responded to *any* of the numbers I suggested, but one thing > still puzzles me. > > Why worry about increasing Q above 500, when you can get more > than the extra 0.2% (lost energy at Q=500) by adding 3 inches > more antenna wire? Possible answer: Because, if you actually need Q=500 for selectivity, an LC tank with an unloaded Q of 500 leaves you no power to drive an earphone? And any improvement in unloaded tank 'Q' translates directly into more power available for audio output? Cheers, James Arthur (who has *no* dog in this fight!)
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| From | krw@notreal.com |
|---|---|
| Date | 2017-03-31 20:08 -0400 |
| Message-ID | <vkrtdc9gmirapl86hg63g846e265cpphvq@4ax.com> |
| In reply to | #454337 |
On Thu, 30 Mar 2017 21:40:29 -0700 (PDT), dagmargoodboat@yahoo.com wrote: >On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote: >> On 29/03/17 02:12, amdx wrote: >> > On 3/28/2017 2:22 AM, Clifford Heath wrote: >> >> On 28/03/17 13:18, amdx wrote: >> >>> On 3/27/2017 6:16 PM, Clifford Heath wrote: >> >>>> On 27/03/17 23:25, amdx wrote: >> >>>>> On 3/27/2017 6:57 AM, Tauno Voipio wrote: >> >>>>>> Joerg, you seem not understand the innermost sense of the crystal- >> >>>>>> radio people. They are closely related to audiophools, and it is >> >>>>>> quite impossible to use sensible technical argumentation here. >> >>>>> >> >>>>> I don't get that at all, can you back that up with any facts? >> >>>> >> >>>> ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? >> >>> >> >>> You haven't connected an antenna, and tried to drive a headset yet. >> >> >> >> Umm, I think that was me in about 1971. >> > >> >> >> >>>> More voltage does not create better audio. >> >>> >> >>> But if it is a very weak signal on the antenna, you don't want to >> >>> waste any signal in loss resistances. >> >> >> >> You start to *reject* some of the received power as soon as the >> >> Q passes 200ish, and you destroy the audio at the same time. >> >> >> >> You can quadruple your received power by doubling your coil >> >> diameter, or fitting a longer wire. That's *far* FAR more >> >> effective than saving 0.2% by using higher Q. >> > >> > Crystal radios do not use the coil to collect RF energy from the air, >> > a long wire antenna of 25ft to 150 is attached tothe coil to pickup the >> > RF signal. >> > If you want to discuss loop antennas, start a new thread. >> > >> > >> >> With a crystal ear-piece, you still may have an impedance matching >> >> problem. For that, you should use an audio transformer *after* >> >> the detector. >> >> >> >> Sorry to puncture your dogma. >> > >> > Take a breath! >> > I'll start simple, Coil and tuning cap have a unloaded Q of >> > 1000. To extract maximum power you use a load that matches the >> > Q times Xl of the coil. Loading the coil with it's matched >> > impedance lowers the Q to 500. >> >> You're making slightly more sense than Rickman, who hasn't >> responded to *any* of the numbers I suggested, but one thing >> still puzzles me. >> >> Why worry about increasing Q above 500, when you can get more >> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >> more antenna wire? > >Possible answer: > >Because, if you actually need Q=500 for selectivity, an LC tank >with an unloaded Q of 500 leaves you no power to drive an earphone? >And any improvement in unloaded tank 'Q' translates directly into more >power available for audio output? Or looking at it another way, you want the loaded Q to be high enough to pass the signal but not the out-of-band noise. Since you're loading the tank with a head set, you need the unloaded Q much higher. >Cheers, >James Arthur (who has *no* dog in this fight!) Only cats here.
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| From | Clifford Heath <no.spam@please.net> |
|---|---|
| Date | 2017-04-02 12:59 +1000 |
| Message-ID | <58e0695b$0$38578$b1db1813$2411a48f@news.astraweb.com> |
| In reply to | #454337 |
On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote: > On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote: >> On 29/03/17 02:12, amdx wrote: >>> On 3/28/2017 2:22 AM, Clifford Heath wrote: >>>> On 28/03/17 13:18, amdx wrote: >>>>> On 3/27/2017 6:16 PM, Clifford Heath wrote: >>>>>> On 27/03/17 23:25, amdx wrote: >>>>>>> On 3/27/2017 6:57 AM, Tauno Voipio wrote: >>>>>>>> Joerg, you seem not understand the innermost sense of the crystal- >>>>>>>> radio people. They are closely related to audiophools, and it is >>>>>>>> quite impossible to use sensible technical argumentation here. >>>>>>> >>>>>>> I don't get that at all, can you back that up with any facts? >>>>>> >>>>>> ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? >>>>> >>>>> You haven't connected an antenna, and tried to drive a headset yet. >>>> >>>> Umm, I think that was me in about 1971. >>> >>>> >>>>>> More voltage does not create better audio. >>>>> >>>>> But if it is a very weak signal on the antenna, you don't want to >>>>> waste any signal in loss resistances. >>>> >>>> You start to *reject* some of the received power as soon as the >>>> Q passes 200ish, and you destroy the audio at the same time. >>>> >>>> You can quadruple your received power by doubling your coil >>>> diameter, or fitting a longer wire. That's *far* FAR more >>>> effective than saving 0.2% by using higher Q. >>> >>> Crystal radios do not use the coil to collect RF energy from the air, >>> a long wire antenna of 25ft to 150 is attached tothe coil to pickup the >>> RF signal. >>> If you want to discuss loop antennas, start a new thread. >>> >>> >>>> With a crystal ear-piece, you still may have an impedance matching >>>> problem. For that, you should use an audio transformer *after* >>>> the detector. >>>> >>>> Sorry to puncture your dogma. >>> >>> Take a breath! >>> I'll start simple, Coil and tuning cap have a unloaded Q of >>> 1000. To extract maximum power you use a load that matches the >>> Q times Xl of the coil. Loading the coil with it's matched >>> impedance lowers the Q to 500. >> >> You're making slightly more sense than Rickman, who hasn't >> responded to *any* of the numbers I suggested, but one thing >> still puzzles me. >> >> Why worry about increasing Q above 500, when you can get more >> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >> more antenna wire? > > Possible answer: > > Because, if you actually need Q=500 for selectivity, an LC tank > with an unloaded Q of 500 leaves you no power to drive an earphone? > And any improvement in unloaded tank 'Q' translates directly into more > power available for audio output? James, thanks. That's the sanest answer yet and goes some way to explaining what the xtal guys are after. However, the single-diode detector is a very assymetric load. That's going to affect things a bit, don't you think? By which I mean that the coil will "see" the load during rising amplitude, but not during falling amplitude. The coupling to a crystal earpiece (generally capacitive, but highly reactive load) is gonna make quite things weird, by pulling the resonant frequency around a lot, dependent on the audio signal... I should pull out my old xtal earpieces and measure the capacitance. I suspect they'd detune a high-Q front end quite a bit, and that really calls into question the use of Q to limit bandwidth. Clifford Heath.
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-04-01 23:55 -0400 |
| Message-ID | <obpshp$djn$1@dont-email.me> |
| In reply to | #454710 |
On 4/1/2017 10:59 PM, Clifford Heath wrote: > On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote: >> On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote: >>> On 29/03/17 02:12, amdx wrote: >>>> On 3/28/2017 2:22 AM, Clifford Heath wrote: >>>>> On 28/03/17 13:18, amdx wrote: >>>>>> On 3/27/2017 6:16 PM, Clifford Heath wrote: >>>>>>> On 27/03/17 23:25, amdx wrote: >>>>>>>> On 3/27/2017 6:57 AM, Tauno Voipio wrote: >>>>>>>>> Joerg, you seem not understand the innermost sense of the crystal- >>>>>>>>> radio people. They are closely related to audiophools, and it is >>>>>>>>> quite impossible to use sensible technical argumentation here. >>>>>>>> >>>>>>>> I don't get that at all, can you back that up with any facts? >>>>>>> >>>>>>> ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? >>>>>> >>>>>> You haven't connected an antenna, and tried to drive a headset yet. >>>>> >>>>> Umm, I think that was me in about 1971. >>>> >>>>> >>>>>>> More voltage does not create better audio. >>>>>> >>>>>> But if it is a very weak signal on the antenna, you don't want to >>>>>> waste any signal in loss resistances. >>>>> >>>>> You start to *reject* some of the received power as soon as the >>>>> Q passes 200ish, and you destroy the audio at the same time. >>>>> >>>>> You can quadruple your received power by doubling your coil >>>>> diameter, or fitting a longer wire. That's *far* FAR more >>>>> effective than saving 0.2% by using higher Q. >>>> >>>> Crystal radios do not use the coil to collect RF energy from the air, >>>> a long wire antenna of 25ft to 150 is attached tothe coil to pickup the >>>> RF signal. >>>> If you want to discuss loop antennas, start a new thread. >>>> >>>> >>>>> With a crystal ear-piece, you still may have an impedance matching >>>>> problem. For that, you should use an audio transformer *after* >>>>> the detector. >>>>> >>>>> Sorry to puncture your dogma. >>>> >>>> Take a breath! >>>> I'll start simple, Coil and tuning cap have a unloaded Q of >>>> 1000. To extract maximum power you use a load that matches the >>>> Q times Xl of the coil. Loading the coil with it's matched >>>> impedance lowers the Q to 500. >>> >>> You're making slightly more sense than Rickman, who hasn't >>> responded to *any* of the numbers I suggested, but one thing >>> still puzzles me. >>> >>> Why worry about increasing Q above 500, when you can get more >>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >>> more antenna wire? >> >> Possible answer: >> >> Because, if you actually need Q=500 for selectivity, an LC tank >> with an unloaded Q of 500 leaves you no power to drive an earphone? >> And any improvement in unloaded tank 'Q' translates directly into more >> power available for audio output? > > James, thanks. > > That's the sanest answer yet and goes some way to explaining > what the xtal guys are after. > > However, the single-diode detector is a very assymetric load. > That's going to affect things a bit, don't you think? By which > I mean that the coil will "see" the load during rising amplitude, > but not during falling amplitude. The coupling to a crystal > earpiece (generally capacitive, but highly reactive load) is > gonna make quite things weird, by pulling the resonant frequency > around a lot, dependent on the audio signal... > > I should pull out my old xtal earpieces and measure the capacitance. > I suspect they'd detune a high-Q front end quite a bit, and that > really calls into question the use of Q to limit bandwidth. I'm unclear what you are describing. When you say "detune" you are not describing an effect on the Q, but rather an effect on the tuned frequency. If the capacitance of the earpiece impacts the tuning of the receiver, the adjustment of the tuning capacitor would make up for that when operated. Or do you mean detune as a way of describing the reduced Q from the loading of the circuit by the earpiece? How exactly would the capacitance of a crystal earpiece affect the loading? When you measure the capacitance of the earpiece, also measure the resistance at audio frequencies. The capacitance is only significant in that context. I believe a serious crystal set operator will use high end headphones however. I believe various military headsets are valued for this use due to their high sensitivity. So the functioning of an inexpensive peizo earpiece may not be so relevant, but interesting anyway. When I read about the detail explored to characterize the detecting diode I was very impressed. So I can see every part of such a simple radio being optimized to the nth degree. -- Rick C
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| From | Clifford Heath <no.spam@please.net> |
|---|---|
| Date | 2017-04-02 14:36 +1000 |
| Message-ID | <58e07ff4$0$43893$c3e8da3$5e5e430d@news.astraweb.com> |
| In reply to | #454717 |
On 02/04/17 13:55, rickman wrote: > On 4/1/2017 10:59 PM, Clifford Heath wrote: >> On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote: >>> On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote: >>>> On 29/03/17 02:12, amdx wrote: >>>>> On 3/28/2017 2:22 AM, Clifford Heath wrote: >>>>>> On 28/03/17 13:18, amdx wrote: >>>>>>> On 3/27/2017 6:16 PM, Clifford Heath wrote: >>>>>>>> On 27/03/17 23:25, amdx wrote: >>>>>>>>> On 3/27/2017 6:57 AM, Tauno Voipio wrote: >>>>>>>>>> Joerg, you seem not understand the innermost sense of the >>>>>>>>>> crystal- >>>>>>>>>> radio people. They are closely related to audiophools, and it is >>>>>>>>>> quite impossible to use sensible technical argumentation here. >>>>>>>>> >>>>>>>>> I don't get that at all, can you back that up with any facts? >>>>>>>> >>>>>>>> ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? >>>>>>> >>>>>>> You haven't connected an antenna, and tried to drive a headset yet. >>>>>> >>>>>> Umm, I think that was me in about 1971. >>>>> >>>>>> >>>>>>>> More voltage does not create better audio. >>>>>>> >>>>>>> But if it is a very weak signal on the antenna, you don't want to >>>>>>> waste any signal in loss resistances. >>>>>> >>>>>> You start to *reject* some of the received power as soon as the >>>>>> Q passes 200ish, and you destroy the audio at the same time. >>>>>> >>>>>> You can quadruple your received power by doubling your coil >>>>>> diameter, or fitting a longer wire. That's *far* FAR more >>>>>> effective than saving 0.2% by using higher Q. >>>>> >>>>> Crystal radios do not use the coil to collect RF energy from the air, >>>>> a long wire antenna of 25ft to 150 is attached tothe coil to pickup >>>>> the >>>>> RF signal. >>>>> If you want to discuss loop antennas, start a new thread. >>>>> >>>>> >>>>>> With a crystal ear-piece, you still may have an impedance matching >>>>>> problem. For that, you should use an audio transformer *after* >>>>>> the detector. >>>>>> >>>>>> Sorry to puncture your dogma. >>>>> >>>>> Take a breath! >>>>> I'll start simple, Coil and tuning cap have a unloaded Q of >>>>> 1000. To extract maximum power you use a load that matches the >>>>> Q times Xl of the coil. Loading the coil with it's matched >>>>> impedance lowers the Q to 500. >>>> >>>> You're making slightly more sense than Rickman, who hasn't >>>> responded to *any* of the numbers I suggested, but one thing >>>> still puzzles me. >>>> >>>> Why worry about increasing Q above 500, when you can get more >>>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >>>> more antenna wire? >>> >>> Possible answer: >>> >>> Because, if you actually need Q=500 for selectivity, an LC tank >>> with an unloaded Q of 500 leaves you no power to drive an earphone? >>> And any improvement in unloaded tank 'Q' translates directly into more >>> power available for audio output? >> >> James, thanks. >> >> That's the sanest answer yet and goes some way to explaining >> what the xtal guys are after. >> >> However, the single-diode detector is a very assymetric load. >> That's going to affect things a bit, don't you think? By which >> I mean that the coil will "see" the load during rising amplitude, >> but not during falling amplitude. The coupling to a crystal >> earpiece (generally capacitive, but highly reactive load) is >> gonna make quite things weird, by pulling the resonant frequency >> around a lot, dependent on the audio signal... >> >> I should pull out my old xtal earpieces and measure the capacitance. >> I suspect they'd detune a high-Q front end quite a bit, and that >> really calls into question the use of Q to limit bandwidth. > > I'm unclear what you are describing. When you say "detune" you are not > describing an effect on the Q, but rather an effect on the tuned > frequency. Both. When the diode conducts (as it must to transmit power) it connects the filter capacitance and the capacitance of the earpiece to the tuned circuit. This will happen whenever the diode is forward biassed, i.e. when the audio signal is rising. The extra capacitance on rising audio signals will pull the tuned circuit to a much lower frequency. As soon as the diode turns off (when the audio signal starts to fall), the tuned circuit will jump to a higher frequency, perhaps receiving a different station, and hence affecting the audio signal once again. I would expect a double-hump response in the overall receiver, and the gap between the humps will depend on the filter and earpiece capacitance. > If the capacitance of the earpiece impacts the tuning of the > receiver, the adjustment of the tuning capacitor would make up for that > when operated. > > Or do you mean detune as a way of describing the reduced Q from the > loading of the circuit by the earpiece? How exactly would the > capacitance of a crystal earpiece affect the loading? > > When you measure the capacitance of the earpiece, also measure the > resistance at audio frequencies. The capacitance is only significant in > that context. Fair enough. I think I've given some answers above. > I believe a serious crystal set operator will use high end headphones > however. I believe various military headsets are valued for this use > due to their high sensitivity. So the functioning of an inexpensive > peizo earpiece may not be so relevant, but interesting anyway. When I > read about the detail explored to characterize the detecting diode I was > very impressed. So I can see every part of such a simple radio being > optimized to the nth degree. Perhaps. The earpiece still has to present some load, or it will receive no energy. For optimum power transfer, you want its audio impedance to roughly approximate the equivalent parallel resistance across the tank - which is why Q gets halved. Or not... perhaps that only happens on audio half-cycles. Anyhow, those are the reasons for my skepticism about the whole project. If the detector and earpiece presented a purely resistive load, or even a fixed capacitive+R load, regardless of audio polarity, then you wouldn't get a double hump. But I think that's unlikely. Clifford Heath.
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-04-02 01:56 -0400 |
| Message-ID | <obq3kh$skm$1@dont-email.me> |
| In reply to | #454728 |
On 4/2/2017 12:36 AM, Clifford Heath wrote: > On 02/04/17 13:55, rickman wrote: >> On 4/1/2017 10:59 PM, Clifford Heath wrote: >>> On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote: >>>> On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote: >>>>> On 29/03/17 02:12, amdx wrote: >>>>>> On 3/28/2017 2:22 AM, Clifford Heath wrote: >>>>>>> On 28/03/17 13:18, amdx wrote: >>>>>>>> On 3/27/2017 6:16 PM, Clifford Heath wrote: >>>>>>>>> On 27/03/17 23:25, amdx wrote: >>>>>>>>>> On 3/27/2017 6:57 AM, Tauno Voipio wrote: >>>>>>>>>>> Joerg, you seem not understand the innermost sense of the >>>>>>>>>>> crystal- >>>>>>>>>>> radio people. They are closely related to audiophools, and it is >>>>>>>>>>> quite impossible to use sensible technical argumentation here. >>>>>>>>>> >>>>>>>>>> I don't get that at all, can you back that up with any facts? >>>>>>>>> >>>>>>>>> ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? >>>>>>>> >>>>>>>> You haven't connected an antenna, and tried to drive a headset >>>>>>>> yet. >>>>>>> >>>>>>> Umm, I think that was me in about 1971. >>>>>> >>>>>>> >>>>>>>>> More voltage does not create better audio. >>>>>>>> >>>>>>>> But if it is a very weak signal on the antenna, you don't want to >>>>>>>> waste any signal in loss resistances. >>>>>>> >>>>>>> You start to *reject* some of the received power as soon as the >>>>>>> Q passes 200ish, and you destroy the audio at the same time. >>>>>>> >>>>>>> You can quadruple your received power by doubling your coil >>>>>>> diameter, or fitting a longer wire. That's *far* FAR more >>>>>>> effective than saving 0.2% by using higher Q. >>>>>> >>>>>> Crystal radios do not use the coil to collect RF energy from the >>>>>> air, >>>>>> a long wire antenna of 25ft to 150 is attached tothe coil to pickup >>>>>> the >>>>>> RF signal. >>>>>> If you want to discuss loop antennas, start a new thread. >>>>>> >>>>>> >>>>>>> With a crystal ear-piece, you still may have an impedance matching >>>>>>> problem. For that, you should use an audio transformer *after* >>>>>>> the detector. >>>>>>> >>>>>>> Sorry to puncture your dogma. >>>>>> >>>>>> Take a breath! >>>>>> I'll start simple, Coil and tuning cap have a unloaded Q of >>>>>> 1000. To extract maximum power you use a load that matches the >>>>>> Q times Xl of the coil. Loading the coil with it's matched >>>>>> impedance lowers the Q to 500. >>>>> >>>>> You're making slightly more sense than Rickman, who hasn't >>>>> responded to *any* of the numbers I suggested, but one thing >>>>> still puzzles me. >>>>> >>>>> Why worry about increasing Q above 500, when you can get more >>>>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >>>>> more antenna wire? >>>> >>>> Possible answer: >>>> >>>> Because, if you actually need Q=500 for selectivity, an LC tank >>>> with an unloaded Q of 500 leaves you no power to drive an earphone? >>>> And any improvement in unloaded tank 'Q' translates directly into more >>>> power available for audio output? >>> >>> James, thanks. >>> >>> That's the sanest answer yet and goes some way to explaining >>> what the xtal guys are after. >>> >>> However, the single-diode detector is a very assymetric load. >>> That's going to affect things a bit, don't you think? By which >>> I mean that the coil will "see" the load during rising amplitude, >>> but not during falling amplitude. The coupling to a crystal >>> earpiece (generally capacitive, but highly reactive load) is >>> gonna make quite things weird, by pulling the resonant frequency >>> around a lot, dependent on the audio signal... >>> >>> I should pull out my old xtal earpieces and measure the capacitance. >>> I suspect they'd detune a high-Q front end quite a bit, and that >>> really calls into question the use of Q to limit bandwidth. >> >> I'm unclear what you are describing. When you say "detune" you are not >> describing an effect on the Q, but rather an effect on the tuned >> frequency. > > Both. When the diode conducts (as it must to transmit power) > it connects the filter capacitance and the capacitance of the > earpiece to the tuned circuit. This will happen whenever the > diode is forward biassed, i.e. when the audio signal is rising. > > The extra capacitance on rising audio signals will pull the tuned > circuit to a much lower frequency. As soon as the diode turns off > (when the audio signal starts to fall), the tuned circuit will > jump to a higher frequency, perhaps receiving a different station, > and hence affecting the audio signal once again. > > I would expect a double-hump response in the overall receiver, > and the gap between the humps will depend on the filter and > earpiece capacitance. Maybe you could build one and test that? >> If the capacitance of the earpiece impacts the tuning of the >> receiver, the adjustment of the tuning capacitor would make up for that >> when operated. >> >> Or do you mean detune as a way of describing the reduced Q from the >> loading of the circuit by the earpiece? How exactly would the >> capacitance of a crystal earpiece affect the loading? >> >> When you measure the capacitance of the earpiece, also measure the >> resistance at audio frequencies. The capacitance is only significant in >> that context. > > Fair enough. I think I've given some answers above. > >> I believe a serious crystal set operator will use high end headphones >> however. I believe various military headsets are valued for this use >> due to their high sensitivity. So the functioning of an inexpensive >> peizo earpiece may not be so relevant, but interesting anyway. When I >> read about the detail explored to characterize the detecting diode I was >> very impressed. So I can see every part of such a simple radio being >> optimized to the nth degree. > > Perhaps. The earpiece still has to present some load, or it will > receive no energy. For optimum power transfer, you want its audio > impedance to roughly approximate the equivalent parallel resistance > across the tank - which is why Q gets halved. Or not... perhaps > that only happens on audio half-cycles. "Presenting a load" is a description of the power transfer. Of course that has to happen or you don't hear a signal. But how much of that power gets converted to sound depends on the earpiece used. > Anyhow, those are the reasons for my skepticism about the whole > project. If the detector and earpiece presented a purely resistive > load, or even a fixed capacitive+R load, regardless of audio > polarity, then you wouldn't get a double hump. But I think that's > unlikely. Theory is nice, but it is easy to miss important aspects. That's why people build crystal radios, to learn what is important and what is not. -- Rick C
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| From | Clifford Heath <no.spam@please.net> |
|---|---|
| Date | 2017-04-02 18:11 +1000 |
| Message-ID | <58e0b28a$0$53003$c3e8da3$fdf4f6af@news.astraweb.com> |
| In reply to | #454738 |
On 02/04/17 15:56, rickman wrote: > On 4/2/2017 12:36 AM, Clifford Heath wrote: >> On 02/04/17 13:55, rickman wrote: >>> On 4/1/2017 10:59 PM, Clifford Heath wrote: >>>> On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote: >>>>> On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath >>>>> wrote: >>>>>> On 29/03/17 02:12, amdx wrote: >>>>>>> On 3/28/2017 2:22 AM, Clifford Heath wrote: >>>>>>>> On 28/03/17 13:18, amdx wrote: >>>>>>>>> On 3/27/2017 6:16 PM, Clifford Heath wrote: >>>>>>>>>> On 27/03/17 23:25, amdx wrote: >>>>>>>>>>> On 3/27/2017 6:57 AM, Tauno Voipio wrote: >>>>>>>>>>>> Joerg, you seem not understand the innermost sense of the >>>>>>>>>>>> crystal- >>>>>>>>>>>> radio people. They are closely related to audiophools, and >>>>>>>>>>>> it is >>>>>>>>>>>> quite impossible to use sensible technical argumentation here. >>>>>>>>>>> >>>>>>>>>>> I don't get that at all, can you back that up with any facts? >>>>>>>>>> >>>>>>>>>> ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? >>>>>>>>> >>>>>>>>> You haven't connected an antenna, and tried to drive a headset >>>>>>>>> yet. >>>>>>>> >>>>>>>> Umm, I think that was me in about 1971. >>>>>>> >>>>>>>> >>>>>>>>>> More voltage does not create better audio. >>>>>>>>> >>>>>>>>> But if it is a very weak signal on the antenna, you don't >>>>>>>>> want to >>>>>>>>> waste any signal in loss resistances. >>>>>>>> >>>>>>>> You start to *reject* some of the received power as soon as the >>>>>>>> Q passes 200ish, and you destroy the audio at the same time. >>>>>>>> >>>>>>>> You can quadruple your received power by doubling your coil >>>>>>>> diameter, or fitting a longer wire. That's *far* FAR more >>>>>>>> effective than saving 0.2% by using higher Q. >>>>>>> >>>>>>> Crystal radios do not use the coil to collect RF energy from the >>>>>>> air, >>>>>>> a long wire antenna of 25ft to 150 is attached tothe coil to pickup >>>>>>> the >>>>>>> RF signal. >>>>>>> If you want to discuss loop antennas, start a new thread. >>>>>>> >>>>>>> >>>>>>>> With a crystal ear-piece, you still may have an impedance matching >>>>>>>> problem. For that, you should use an audio transformer *after* >>>>>>>> the detector. >>>>>>>> >>>>>>>> Sorry to puncture your dogma. >>>>>>> >>>>>>> Take a breath! >>>>>>> I'll start simple, Coil and tuning cap have a unloaded Q of >>>>>>> 1000. To extract maximum power you use a load that matches the >>>>>>> Q times Xl of the coil. Loading the coil with it's matched >>>>>>> impedance lowers the Q to 500. >>>>>> >>>>>> You're making slightly more sense than Rickman, who hasn't >>>>>> responded to *any* of the numbers I suggested, but one thing >>>>>> still puzzles me. >>>>>> >>>>>> Why worry about increasing Q above 500, when you can get more >>>>>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >>>>>> more antenna wire? >>>>> >>>>> Possible answer: >>>>> >>>>> Because, if you actually need Q=500 for selectivity, an LC tank >>>>> with an unloaded Q of 500 leaves you no power to drive an earphone? >>>>> And any improvement in unloaded tank 'Q' translates directly into more >>>>> power available for audio output? >>>> >>>> James, thanks. >>>> >>>> That's the sanest answer yet and goes some way to explaining >>>> what the xtal guys are after. >>>> >>>> However, the single-diode detector is a very assymetric load. >>>> That's going to affect things a bit, don't you think? By which >>>> I mean that the coil will "see" the load during rising amplitude, >>>> but not during falling amplitude. The coupling to a crystal >>>> earpiece (generally capacitive, but highly reactive load) is >>>> gonna make quite things weird, by pulling the resonant frequency >>>> around a lot, dependent on the audio signal... >>>> >>>> I should pull out my old xtal earpieces and measure the capacitance. >>>> I suspect they'd detune a high-Q front end quite a bit, and that >>>> really calls into question the use of Q to limit bandwidth. >>> >>> I'm unclear what you are describing. When you say "detune" you are not >>> describing an effect on the Q, but rather an effect on the tuned >>> frequency. >> >> Both. When the diode conducts (as it must to transmit power) >> it connects the filter capacitance and the capacitance of the >> earpiece to the tuned circuit. This will happen whenever the >> diode is forward biassed, i.e. when the audio signal is rising. >> >> The extra capacitance on rising audio signals will pull the tuned >> circuit to a much lower frequency. As soon as the diode turns off >> (when the audio signal starts to fall), the tuned circuit will >> jump to a higher frequency, perhaps receiving a different station, >> and hence affecting the audio signal once again. >> >> I would expect a double-hump response in the overall receiver, >> and the gap between the humps will depend on the filter and >> earpiece capacitance. > > Maybe you could build one and test that? > > >>> If the capacitance of the earpiece impacts the tuning of the >>> receiver, the adjustment of the tuning capacitor would make up for that >>> when operated. >>> >>> Or do you mean detune as a way of describing the reduced Q from the >>> loading of the circuit by the earpiece? How exactly would the >>> capacitance of a crystal earpiece affect the loading? >>> >>> When you measure the capacitance of the earpiece, also measure the >>> resistance at audio frequencies. The capacitance is only significant in >>> that context. >> >> Fair enough. I think I've given some answers above. >> >>> I believe a serious crystal set operator will use high end headphones >>> however. I believe various military headsets are valued for this use >>> due to their high sensitivity. So the functioning of an inexpensive >>> peizo earpiece may not be so relevant, but interesting anyway. When I >>> read about the detail explored to characterize the detecting diode I was >>> very impressed. So I can see every part of such a simple radio being >>> optimized to the nth degree. >> >> Perhaps. The earpiece still has to present some load, or it will >> receive no energy. For optimum power transfer, you want its audio >> impedance to roughly approximate the equivalent parallel resistance >> across the tank - which is why Q gets halved. Or not... perhaps >> that only happens on audio half-cycles. > > "Presenting a load" is a description of the power transfer. Of course > that has to happen or you don't hear a signal. But how much of that > power gets converted to sound depends on the earpiece used. > > >> Anyhow, those are the reasons for my skepticism about the whole >> project. If the detector and earpiece presented a purely resistive >> load, or even a fixed capacitive+R load, regardless of audio >> polarity, then you wouldn't get a double hump. But I think that's >> unlikely. > > Theory is nice, but it is easy to miss important aspects. That's why > people build crystal radios, to learn what is important and what is not. It would need a fairly ornate test setup compared to what I have available; specifically two different signals, one fixed, one swept, to see at what frequencies the swept one gets in. Possible, but I can't easily do it at present. It seems easier to just ask: with your high-Q receiver, do you ever hear two stations at the same time that are on different frequencies? What do the community report? The crystal set I built as a kid seemed often to get multiple stations, but it probably didn't have enough pixie dust. Clifford Heath
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| From | amdx <nojunk@knology.net> |
|---|---|
| Date | 2017-04-02 07:35 -0500 |
| Message-ID | <obqr1k$117$1@dont-email.me> |
| In reply to | #454749 |
On 4/2/2017 3:11 AM, Clifford Heath wrote:
> On 02/04/17 15:56, rickman wrote:
>> On 4/2/2017 12:36 AM, Clifford Heath wrote:
>>> On 02/04/17 13:55, rickman wrote:
>>>> On 4/1/2017 10:59 PM, Clifford Heath wrote:
>>>>> On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote:
>>>>>> On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath
>>>>>> wrote:
>>>>>>> On 29/03/17 02:12, amdx wrote:
>>>>>>>> On 3/28/2017 2:22 AM, Clifford Heath wrote:
>>>>>>>>> On 28/03/17 13:18, amdx wrote:
>>>>>>>>>> On 3/27/2017 6:16 PM, Clifford Heath wrote:
>>>>>>>>>>> On 27/03/17 23:25, amdx wrote:
>>>>>>>>>>>> On 3/27/2017 6:57 AM, Tauno Voipio wrote:
>>>>>>>>>>>>> Joerg, you seem not understand the innermost sense of the
>>>>>>>>>>>>> crystal-
>>>>>>>>>>>>> radio people. They are closely related to audiophools, and
>>>>>>>>>>>>> it is
>>>>>>>>>>>>> quite impossible to use sensible technical argumentation here.
>>>>>>>>>>>>
>>>>>>>>>>>> I don't get that at all, can you back that up with any facts?
>>>>>>>>>>>
>>>>>>>>>>> ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500?
>>>>>>>>>>
>>>>>>>>>> You haven't connected an antenna, and tried to drive a headset
>>>>>>>>>> yet.
>>>>>>>>>
>>>>>>>>> Umm, I think that was me in about 1971.
>>>>>>>>
>>>>>>>>>
>>>>>>>>>>> More voltage does not create better audio.
>>>>>>>>>>
>>>>>>>>>> But if it is a very weak signal on the antenna, you don't
>>>>>>>>>> want to
>>>>>>>>>> waste any signal in loss resistances.
>>>>>>>>>
>>>>>>>>> You start to *reject* some of the received power as soon as the
>>>>>>>>> Q passes 200ish, and you destroy the audio at the same time.
>>>>>>>>>
>>>>>>>>> You can quadruple your received power by doubling your coil
>>>>>>>>> diameter, or fitting a longer wire. That's *far* FAR more
>>>>>>>>> effective than saving 0.2% by using higher Q.
>>>>>>>>
>>>>>>>> Crystal radios do not use the coil to collect RF energy from the
>>>>>>>> air,
>>>>>>>> a long wire antenna of 25ft to 150 is attached tothe coil to pickup
>>>>>>>> the
>>>>>>>> RF signal.
>>>>>>>> If you want to discuss loop antennas, start a new thread.
>>>>>>>>
>>>>>>>>
>>>>>>>>> With a crystal ear-piece, you still may have an impedance matching
>>>>>>>>> problem. For that, you should use an audio transformer *after*
>>>>>>>>> the detector.
>>>>>>>>>
>>>>>>>>> Sorry to puncture your dogma.
>>>>>>>>
>>>>>>>> Take a breath!
>>>>>>>> I'll start simple, Coil and tuning cap have a unloaded Q of
>>>>>>>> 1000. To extract maximum power you use a load that matches the
>>>>>>>> Q times Xl of the coil. Loading the coil with it's matched
>>>>>>>> impedance lowers the Q to 500.
>>>>>>>
>>>>>>> You're making slightly more sense than Rickman, who hasn't
>>>>>>> responded to *any* of the numbers I suggested, but one thing
>>>>>>> still puzzles me.
>>>>>>>
>>>>>>> Why worry about increasing Q above 500, when you can get more
>>>>>>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches
>>>>>>> more antenna wire?
>>>>>>
>>>>>> Possible answer:
>>>>>>
>>>>>> Because, if you actually need Q=500 for selectivity, an LC tank
>>>>>> with an unloaded Q of 500 leaves you no power to drive an earphone?
>>>>>> And any improvement in unloaded tank 'Q' translates directly into
>>>>>> more
>>>>>> power available for audio output?
>>>>>
>>>>> James, thanks.
>>>>>
>>>>> That's the sanest answer yet and goes some way to explaining
>>>>> what the xtal guys are after.
>>>>>
>>>>> However, the single-diode detector is a very assymetric load.
>>>>> That's going to affect things a bit, don't you think? By which
>>>>> I mean that the coil will "see" the load during rising amplitude,
>>>>> but not during falling amplitude. The coupling to a crystal
>>>>> earpiece (generally capacitive, but highly reactive load) is
>>>>> gonna make quite things weird, by pulling the resonant frequency
>>>>> around a lot, dependent on the audio signal...
>>>>>
>>>>> I should pull out my old xtal earpieces and measure the capacitance.
>>>>> I suspect they'd detune a high-Q front end quite a bit, and that
>>>>> really calls into question the use of Q to limit bandwidth.
>>>>
>>>> I'm unclear what you are describing. When you say "detune" you are not
>>>> describing an effect on the Q, but rather an effect on the tuned
>>>> frequency.
>>>
>>> Both. When the diode conducts (as it must to transmit power)
>>> it connects the filter capacitance and the capacitance of the
>>> earpiece to the tuned circuit. This will happen whenever the
>>> diode is forward biassed, i.e. when the audio signal is rising.
>>>
>>> The extra capacitance on rising audio signals will pull the tuned
>>> circuit to a much lower frequency. As soon as the diode turns off
>>> (when the audio signal starts to fall), the tuned circuit will
>>> jump to a higher frequency, perhaps receiving a different station,
>>> and hence affecting the audio signal once again.
>>>
>>> I would expect a double-hump response in the overall receiver,
>>> and the gap between the humps will depend on the filter and
>>> earpiece capacitance.
>>
>> Maybe you could build one and test that?
>>
>>
>>>> If the capacitance of the earpiece impacts the tuning of the
>>>> receiver, the adjustment of the tuning capacitor would make up for that
>>>> when operated.
>>>>
>>>> Or do you mean detune as a way of describing the reduced Q from the
>>>> loading of the circuit by the earpiece? How exactly would the
>>>> capacitance of a crystal earpiece affect the loading?
>>>>
>>>> When you measure the capacitance of the earpiece, also measure the
>>>> resistance at audio frequencies. The capacitance is only
>>>> significant in
>>>> that context.
>>>
>>> Fair enough. I think I've given some answers above.
>>>
>>>> I believe a serious crystal set operator will use high end headphones
>>>> however. I believe various military headsets are valued for this use
>>>> due to their high sensitivity. So the functioning of an inexpensive
>>>> peizo earpiece may not be so relevant, but interesting anyway. When I
>>>> read about the detail explored to characterize the detecting diode I
>>>> was
>>>> very impressed. So I can see every part of such a simple radio being
>>>> optimized to the nth degree.
>>>
>>> Perhaps. The earpiece still has to present some load, or it will
>>> receive no energy. For optimum power transfer, you want its audio
>>> impedance to roughly approximate the equivalent parallel resistance
>>> across the tank - which is why Q gets halved. Or not... perhaps
>>> that only happens on audio half-cycles.
>>
>> "Presenting a load" is a description of the power transfer. Of course
>> that has to happen or you don't hear a signal. But how much of that
>> power gets converted to sound depends on the earpiece used.
>>
>>
>>> Anyhow, those are the reasons for my skepticism about the whole
>>> project. If the detector and earpiece presented a purely resistive
>>> load, or even a fixed capacitive+R load, regardless of audio
>>> polarity, then you wouldn't get a double hump. But I think that's
>>> unlikely.
>>
>> Theory is nice, but it is easy to miss important aspects. That's why
>> people build crystal radios, to learn what is important and what is not.
>
> It would need a fairly ornate test setup compared to what I have
> available; specifically two different signals, one fixed, one swept,
> to see at what frequencies the swept one gets in. Possible, but I
> can't easily do it at present.
>
> It seems easier to just ask: with your high-Q receiver, do you ever
> hear two stations at the same time that are on different frequencies?
> What do the community reporti
>
> The crystal set I built as a kid seemed often to get multiple stations,
> but it probably didn't have enough pixie dust.
>
> Clifford Heath
If your going to build a high quality crystal set, then your most
likely going to use high end earphones. Some of the most sensitive
are the, "WWII RCA Big Cans MI-2045E US Navy Deck Talkers Headset'
They are magnetic headphones and as best I can find are fairly low
impedance at 300 ohms. That means you need a transformer to match
you high Q LC to the low impedance headphones.
Ben Tongue did work on that, here;
> http://www.bentongue.com/xtalset/5hpXform/5hpXform.html
Page down past Table 7 and see, "A UTC O-15 'Ouncer' transformer"...
In that section he tests a two transformer arrangement that transforms
a 1.3Meg impedance down to 8 ohms, 300 ohms, 1.2k ohms and 10k ohms.
The transformer loss at 8 ohms is 1.2 db at 1kHz, and I suspect a
little less at 300 ohms.
And then there is the sensitivity of different headphones,
Mouser single old style xtal ear plug - 103
RCA big cans - 128 (before alignment)
Mikek
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
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| From | mkolber1@gmail.com |
|---|---|
| Date | 2017-04-02 06:16 -0700 |
| Message-ID | <8b12d900-9406-4cb7-80eb-d8f66566a5d1@googlegroups.com> |
| In reply to | #454755 |
This is a good example that even a "simple" Crystal radio is not so simple if you dig deep enough into the details. M
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| From | Clifford Heath <no.spam@please.net> |
|---|---|
| Date | 2017-04-03 07:40 +1000 |
| Message-ID | <58e17020$0$59620$c3e8da3$460562f1@news.astraweb.com> |
| In reply to | #454755 |
On 02/04/17 22:35, amdx wrote: > On 4/2/2017 3:11 AM, Clifford Heath wrote: >> On 02/04/17 15:56, rickman wrote: >>> On 4/2/2017 12:36 AM, Clifford Heath wrote: >>>> On 02/04/17 13:55, rickman wrote: >>>>> On 4/1/2017 10:59 PM, Clifford Heath wrote: >>>>>> On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote: >>>>>>> On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath >>>>>>> wrote: >>>>>>>> On 29/03/17 02:12, amdx wrote: >>>>>>>>> On 3/28/2017 2:22 AM, Clifford Heath wrote: >>>>>>>>>> On 28/03/17 13:18, amdx wrote: >>>>>>>>>>> On 3/27/2017 6:16 PM, Clifford Heath wrote: >>>>>>>>>>>> On 27/03/17 23:25, amdx wrote: >>>>>>>>>>>>> On 3/27/2017 6:57 AM, Tauno Voipio wrote: >>>>>>>>>>>>>> Joerg, you seem not understand the innermost sense of the >>>>>>>>>>>>>> crystal- >>>>>>>>>>>>>> radio people. They are closely related to audiophools, and >>>>>>>>>>>>>> it is >>>>>>>>>>>>>> quite impossible to use sensible technical argumentation >>>>>>>>>>>>>> here. >>>>>>>>>>>>> >>>>>>>>>>>>> I don't get that at all, can you back that up with any >>>>>>>>>>>>> facts? >>>>>>>>>>>> >>>>>>>>>>>> ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? >>>>>>>>>>> >>>>>>>>>>> You haven't connected an antenna, and tried to drive a headset >>>>>>>>>>> yet. >>>>>>>>>> >>>>>>>>>> Umm, I think that was me in about 1971. >>>>>>>>> >>>>>>>>>> >>>>>>>>>>>> More voltage does not create better audio. >>>>>>>>>>> >>>>>>>>>>> But if it is a very weak signal on the antenna, you don't >>>>>>>>>>> want to >>>>>>>>>>> waste any signal in loss resistances. >>>>>>>>>> >>>>>>>>>> You start to *reject* some of the received power as soon as the >>>>>>>>>> Q passes 200ish, and you destroy the audio at the same time. >>>>>>>>>> >>>>>>>>>> You can quadruple your received power by doubling your coil >>>>>>>>>> diameter, or fitting a longer wire. That's *far* FAR more >>>>>>>>>> effective than saving 0.2% by using higher Q. >>>>>>>>> >>>>>>>>> Crystal radios do not use the coil to collect RF energy from the >>>>>>>>> air, >>>>>>>>> a long wire antenna of 25ft to 150 is attached tothe coil to >>>>>>>>> pickup >>>>>>>>> the >>>>>>>>> RF signal. >>>>>>>>> If you want to discuss loop antennas, start a new thread. >>>>>>>>> >>>>>>>>> >>>>>>>>>> With a crystal ear-piece, you still may have an impedance >>>>>>>>>> matching >>>>>>>>>> problem. For that, you should use an audio transformer *after* >>>>>>>>>> the detector. >>>>>>>>>> >>>>>>>>>> Sorry to puncture your dogma. >>>>>>>>> >>>>>>>>> Take a breath! >>>>>>>>> I'll start simple, Coil and tuning cap have a unloaded Q of >>>>>>>>> 1000. To extract maximum power you use a load that matches the >>>>>>>>> Q times Xl of the coil. Loading the coil with it's matched >>>>>>>>> impedance lowers the Q to 500. >>>>>>>> >>>>>>>> You're making slightly more sense than Rickman, who hasn't >>>>>>>> responded to *any* of the numbers I suggested, but one thing >>>>>>>> still puzzles me. >>>>>>>> >>>>>>>> Why worry about increasing Q above 500, when you can get more >>>>>>>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >>>>>>>> more antenna wire? >>>>>>> >>>>>>> Possible answer: >>>>>>> >>>>>>> Because, if you actually need Q=500 for selectivity, an LC tank >>>>>>> with an unloaded Q of 500 leaves you no power to drive an earphone? >>>>>>> And any improvement in unloaded tank 'Q' translates directly into >>>>>>> more >>>>>>> power available for audio output? >>>>>> >>>>>> James, thanks. >>>>>> >>>>>> That's the sanest answer yet and goes some way to explaining >>>>>> what the xtal guys are after. >>>>>> >>>>>> However, the single-diode detector is a very assymetric load. >>>>>> That's going to affect things a bit, don't you think? By which >>>>>> I mean that the coil will "see" the load during rising amplitude, >>>>>> but not during falling amplitude. The coupling to a crystal >>>>>> earpiece (generally capacitive, but highly reactive load) is >>>>>> gonna make quite things weird, by pulling the resonant frequency >>>>>> around a lot, dependent on the audio signal... >>>>>> >>>>>> I should pull out my old xtal earpieces and measure the capacitance. >>>>>> I suspect they'd detune a high-Q front end quite a bit, and that >>>>>> really calls into question the use of Q to limit bandwidth. >>>>> >>>>> I'm unclear what you are describing. When you say "detune" you are >>>>> not >>>>> describing an effect on the Q, but rather an effect on the tuned >>>>> frequency. >>>> >>>> Both. When the diode conducts (as it must to transmit power) >>>> it connects the filter capacitance and the capacitance of the >>>> earpiece to the tuned circuit. This will happen whenever the >>>> diode is forward biassed, i.e. when the audio signal is rising. >>>> >>>> The extra capacitance on rising audio signals will pull the tuned >>>> circuit to a much lower frequency. As soon as the diode turns off >>>> (when the audio signal starts to fall), the tuned circuit will >>>> jump to a higher frequency, perhaps receiving a different station, >>>> and hence affecting the audio signal once again. >>>> >>>> I would expect a double-hump response in the overall receiver, >>>> and the gap between the humps will depend on the filter and >>>> earpiece capacitance. >>> >>> Maybe you could build one and test that? >>> >>> >>>>> If the capacitance of the earpiece impacts the tuning of the >>>>> receiver, the adjustment of the tuning capacitor would make up for >>>>> that >>>>> when operated. >>>>> >>>>> Or do you mean detune as a way of describing the reduced Q from the >>>>> loading of the circuit by the earpiece? How exactly would the >>>>> capacitance of a crystal earpiece affect the loading? >>>>> >>>>> When you measure the capacitance of the earpiece, also measure the >>>>> resistance at audio frequencies. The capacitance is only >>>>> significant in >>>>> that context. >>>> >>>> Fair enough. I think I've given some answers above. >>>> >>>>> I believe a serious crystal set operator will use high end headphones >>>>> however. I believe various military headsets are valued for this use >>>>> due to their high sensitivity. So the functioning of an inexpensive >>>>> peizo earpiece may not be so relevant, but interesting anyway. When I >>>>> read about the detail explored to characterize the detecting diode I >>>>> was >>>>> very impressed. So I can see every part of such a simple radio being >>>>> optimized to the nth degree. >>>> >>>> Perhaps. The earpiece still has to present some load, or it will >>>> receive no energy. For optimum power transfer, you want its audio >>>> impedance to roughly approximate the equivalent parallel resistance >>>> across the tank - which is why Q gets halved. Or not... perhaps >>>> that only happens on audio half-cycles. >>> >>> "Presenting a load" is a description of the power transfer. Of course >>> that has to happen or you don't hear a signal. But how much of that >>> power gets converted to sound depends on the earpiece used. >>> >>> >>>> Anyhow, those are the reasons for my skepticism about the whole >>>> project. If the detector and earpiece presented a purely resistive >>>> load, or even a fixed capacitive+R load, regardless of audio >>>> polarity, then you wouldn't get a double hump. But I think that's >>>> unlikely. >>> >>> Theory is nice, but it is easy to miss important aspects. That's why >>> people build crystal radios, to learn what is important and what is not. >> >> It would need a fairly ornate test setup compared to what I have >> available; specifically two different signals, one fixed, one swept, >> to see at what frequencies the swept one gets in. Possible, but I >> can't easily do it at present. >> >> It seems easier to just ask: with your high-Q receiver, do you ever >> hear two stations at the same time that are on different frequencies? >> What do the community reporti >> >> The crystal set I built as a kid seemed often to get multiple stations, >> but it probably didn't have enough pixie dust. > > If your going to build a high quality crystal set, then your most > likely going to use high end earphones. Some of the most sensitive > are the, "WWII RCA Big Cans MI-2045E US Navy Deck Talkers Headset' > They are magnetic headphones and as best I can find are fairly low > impedance at 300 ohms. That means you need a transformer to match > you high Q LC to the low impedance headphones. That's good to know, but not relevant to the dual impedance caused by the detector's polarization. I mentioned the peaky resonances in crystal earpieces, but they're not the main problem. > Ben Tongue did work on that, here; >> http://www.bentongue.com/xtalset/5hpXform/5hpXform.html > Page down past Table 7 and see, "A UTC O-15 'Ouncer' transformer"... > In that section he tests a two transformer arrangement that transforms > a 1.3Meg impedance down to 8 ohms, 300 ohms, 1.2k ohms and 10k ohms. > The transformer loss at 8 ohms is 1.2 db at 1kHz, and I suspect a > little less at 300 ohms. > And then there is the sensitivity of different headphones, > > Mouser single old style xtal ear plug - 103 > > RCA big cans - 128 (before alignment) > Mikek > > > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus >
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| From | dagmargoodboat@yahoo.com |
|---|---|
| Date | 2017-04-02 08:12 -0700 |
| Message-ID | <2826a9a6-4926-45f2-a941-051a70ee89ab@googlegroups.com> |
| In reply to | #454710 |
On Saturday, April 1, 2017 at 11:00:54 PM UTC-4, Clifford Heath wrote: > On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote: > > On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote: > >> Why worry about increasing Q above 500, when you can get more > >> than the extra 0.2% (lost energy at Q=500) by adding 3 inches > >> more antenna wire? > > > > Possible answer: > > > > Because, if you actually need Q=500 for selectivity, an LC tank > > with an unloaded Q of 500 leaves you no power to drive an earphone? > > And any improvement in unloaded tank 'Q' translates directly into more > > power available for audio output? > > James, thanks. > > That's the sanest answer yet and goes some way to explaining > what the xtal guys are after. > > However, the single-diode detector is a very assymetric load. > That's going to affect things a bit, don't you think? By which > I mean that the coil will "see" the load during rising amplitude, > but not during falling amplitude. I'm not a crystal radio guy (RFI on my powerline is so bad that I get *no* AM stations)(*), but these pages seem to offer a decent overview: This one-paragraph introduction lays out the big picture: http://www.bentongue.com/xtalset/1nlxtlsd/1nlxtlsd.html A short discussion of detector diodes: http://www.crystal-radio.eu/endiodes.htm Detailed empirical measurements of diode detectors: http://www.crystal-radio.eu/endetunittest1.htm At low signal diodes are square-law detectors, quadrupling output for every doubling in signal voltage. > The coupling to a crystal > earpiece (generally capacitive, but highly reactive load) is > gonna make quite things weird, by pulling the resonant frequency > around a lot, dependent on the audio signal... > > I should pull out my old xtal earpieces and measure the capacitance. > I suspect they'd detune a high-Q front end quite a bit, and that > really calls into question the use of Q to limit bandwidth. These guys' coupling transformers ought to transform (lower) the effective capacitance of any earphone. And any residual capacitance is simply compensated by re-tuning, anyhow. The old crystal earphones were amazing. The crystal radio guys seem to prefer impedance matching with transformers to magnetic earphones. (*) Hey, I just scanned the AM band and the years-standing RFI is gone!! Who knew! Cheers, James Arthur
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| From | Clifford Heath <no.spam@please.net> |
|---|---|
| Date | 2017-04-03 08:47 +1000 |
| Message-ID | <58e17faa$0$3544$b1db1813$65575428@news.astraweb.com> |
| In reply to | #454769 |
On 03/04/17 01:12, dagmargoodboat@yahoo.com wrote: > On Saturday, April 1, 2017 at 11:00:54 PM UTC-4, Clifford Heath wrote: >> On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote: >>> On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote: > >>>> Why worry about increasing Q above 500, when you can get more >>>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches >>>> more antenna wire? >>> >>> Possible answer: >>> >>> Because, if you actually need Q=500 for selectivity, an LC tank >>> with an unloaded Q of 500 leaves you no power to drive an earphone? >>> And any improvement in unloaded tank 'Q' translates directly into more >>> power available for audio output? >> >> James, thanks. >> >> That's the sanest answer yet and goes some way to explaining >> what the xtal guys are after. >> >> However, the single-diode detector is a very assymetric load. >> That's going to affect things a bit, don't you think? By which >> I mean that the coil will "see" the load during rising amplitude, >> but not during falling amplitude. > > I'm not a crystal radio guy (RFI on my powerline is so bad that I get *no* > AM stations)(*), but these pages seem to offer a decent overview: > > This one-paragraph introduction lays out the big picture: > http://www.bentongue.com/xtalset/1nlxtlsd/1nlxtlsd.html > > A short discussion of detector diodes: > http://www.crystal-radio.eu/endiodes.htm > > Detailed empirical measurements of diode detectors: > http://www.crystal-radio.eu/endetunittest1.htm Interesting articles - I just read all three - but none of them mention the effect I'm suggesting, and none of the experimental setups would see it. Ben Tongue gets close in his paragraph "Tuned circuit loss and bandwidth considerations", but doesn't acknowledge the assymetric load characteristic. I bet I could construct an LTSpice simulation that would show it clearly. > At low signal diodes are square-law detectors, quadrupling output for > every doubling in signal voltage. > >> The coupling to a crystal >> earpiece (generally capacitive, but highly reactive load) is >> gonna make quite things weird, by pulling the resonant frequency >> around a lot, dependent on the audio signal... >> >> I should pull out my old xtal earpieces and measure the capacitance. >> I suspect they'd detune a high-Q front end quite a bit, and that >> really calls into question the use of Q to limit bandwidth. > > These guys' coupling transformers ought to transform (lower) the > effective capacitance of any earphone. And any residual capacitance > is simply compensated by re-tuning, anyhow. Yes, but that capacitance is only coupled to the antenna during half-cycles of the audio, while the diode is conducting. So you have two frequencies being tuned. While the diode is off, the alternate frequency is the one which will turn it back on again and slew the tuned frequency to the one you hear. That would explain a lot of what I recall hearing in my crystal earpiece, anyhow; effectively audio intermodulation from adjacent stations. I guess that's why the Benny is useful; not for the reason he describes, but to make the load appear more resistive. Interesting stuff. > (*) Hey, I just scanned the AM band and the years-standing RFI is gone!! Perhaps you replaced a bit of equipment that had a crappy wall wart? Or a neighbour did! Clifford Heath.
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| From | dagmargoodboat@yahoo.com |
|---|---|
| Date | 2017-04-02 18:39 -0700 |
| Message-ID | <a7b84133-576e-480f-b287-11a81ff15ce4@googlegroups.com> |
| In reply to | #454816 |
On Sunday, April 2, 2017 at 6:48:13 PM UTC-4, Clifford Heath wrote: > On 03/04/17 01:12, dagmargoodboat@yahoo.com wrote: > > On Saturday, April 1, 2017 at 11:00:54 PM UTC-4, Clifford Heath wrote: > >> On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote: > >>> On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote: > > > >>>> Why worry about increasing Q above 500, when you can get more > >>>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches > >>>> more antenna wire? > >>> > >>> Possible answer: > >>> > >>> Because, if you actually need Q=500 for selectivity, an LC tank > >>> with an unloaded Q of 500 leaves you no power to drive an earphone? > >>> And any improvement in unloaded tank 'Q' translates directly into more > >>> power available for audio output? > >> > >> James, thanks. > >> > >> That's the sanest answer yet and goes some way to explaining > >> what the xtal guys are after. > >> > >> However, the single-diode detector is a very assymetric load. > >> That's going to affect things a bit, don't you think? By which > >> I mean that the coil will "see" the load during rising amplitude, > >> but not during falling amplitude. > > > > I'm not a crystal radio guy (RFI on my powerline is so bad that I get *no* > > AM stations)(*), but these pages seem to offer a decent overview: > > > > This one-paragraph introduction lays out the big picture: > > http://www.bentongue.com/xtalset/1nlxtlsd/1nlxtlsd.html > > > > A short discussion of detector diodes: > > http://www.crystal-radio.eu/endiodes.htm > > > > Detailed empirical measurements of diode detectors: > > http://www.crystal-radio.eu/endetunittest1.htm > > Interesting articles - I just read all three - but none of them > mention the effect I'm suggesting, and none of the experimental > setups would see it. Ben Tongue gets close in his paragraph > "Tuned circuit loss and bandwidth considerations", but doesn't > acknowledge the assymetric load characteristic. > > I bet I could construct an LTSpice simulation that would show > it clearly. Agreed, you could simulate it, and it isn't addressed in the articles I read, but does it do much other than add a bit of harmonic distortion? I don't see how. > > At low signal diodes are square-law detectors, quadrupling output for > > every doubling in signal voltage. > > > >> The coupling to a crystal > >> earpiece (generally capacitive, but highly reactive load) is > >> gonna make quite things weird, by pulling the resonant frequency > >> around a lot, dependent on the audio signal... > >> > >> I should pull out my old xtal earpieces and measure the capacitance. > >> I suspect they'd detune a high-Q front end quite a bit, and that > >> really calls into question the use of Q to limit bandwidth. > > > > These guys' coupling transformers ought to transform (lower) the > > effective capacitance of any earphone. And any residual capacitance > > is simply compensated by re-tuning, anyhow. > > Yes, but that capacitance is only coupled to the antenna during > half-cycles of the audio, while the diode is conducting. So you > have two frequencies being tuned. While the diode is off, the > alternate frequency is the one which will turn it back on again > and slew the tuned frequency to the one you hear. > > That would explain a lot of what I recall hearing in my crystal > earpiece, anyhow; effectively audio intermodulation from adjacent > stations. That's always a danger in a crowded band, yes. > I guess that's why the Benny is useful; not for the reason he > describes, but to make the load appear more resistive. > > Interesting stuff. > > > (*) Hey, I just scanned the AM band and the years-standing RFI is gone!! > > Perhaps you replaced a bit of equipment that had a crappy wall wart? > Or a neighbour did! Not me, it was far too powerful, and stronger outside than inside. I suspect an aging line and pole replacement program in progress likely removed a HV leaker, somewhere in the neighborhood. RFI was so bad I hadn't bothered checking the AM band in perhaps a year or two--it had been like listening to a Tesla coil or an EDM machine. > Clifford Heath. Cheers, James Arthur
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| From | amdx <nojunk@knology.net> |
|---|---|
| Date | 2017-04-02 21:22 -0500 |
| Message-ID | <obsbfl$8ak$1@dont-email.me> |
| In reply to | #454841 |
On 4/2/2017 8:39 PM, dagmargoodboat@yahoo.com wrote:
> On Sunday, April 2, 2017 at 6:48:13 PM UTC-4, Clifford Heath wrote:
>> On 03/04/17 01:12, dagmargoodboat@yahoo.com wrote:
>>> On Saturday, April 1, 2017 at 11:00:54 PM UTC-4, Clifford Heath wrote:
>>>> On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote:
>>>>> On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote:
>>>
>>>>>> Why worry about increasing Q above 500, when you can get more
>>>>>> than the extra 0.2% (lost energy at Q=500) by adding 3 inches
>>>>>> more antenna wire?
>>>>>
>>>>> Possible answer:
>>>>>
>>>>> Because, if you actually need Q=500 for selectivity, an LC tank
>>>>> with an unloaded Q of 500 leaves you no power to drive an earphone?
>>>>> And any improvement in unloaded tank 'Q' translates directly into more
>>>>> power available for audio output?
>>>>
>>>> James, thanks.
>>>>
>>>> That's the sanest answer yet and goes some way to explaining
>>>> what the xtal guys are after.
>>>>
>>>> However, the single-diode detector is a very assymetric load.
>>>> That's going to affect things a bit, don't you think? By which
>>>> I mean that the coil will "see" the load during rising amplitude,
>>>> but not during falling amplitude.
>>>
>>> I'm not a crystal radio guy (RFI on my powerline is so bad that I get *no*
>>> AM stations)(*), but these pages seem to offer a decent overview:
>>>
>>> This one-paragraph introduction lays out the big picture:
>>> http://www.bentongue.com/xtalset/1nlxtlsd/1nlxtlsd.html
>>>
>>> A short discussion of detector diodes:
>>> http://www.crystal-radio.eu/endiodes.htm
>>>
>>> Detailed empirical measurements of diode detectors:
>>> http://www.crystal-radio.eu/endetunittest1.htm
>>
>> Interesting articles - I just read all three - but none of them
>> mention the effect I'm suggesting, and none of the experimental
>> setups would see it. Ben Tongue gets close in his paragraph
>> "Tuned circuit loss and bandwidth considerations", but doesn't
>> acknowledge the assymetric load characteristic.
>>
>> I bet I could construct an LTSpice simulation that would show
>> it clearly.
>
> Agreed, you could simulate it, and it isn't addressed in the articles
> I read, but does it do much other than add a bit of harmonic distortion?
> I don't see how.
>
>>> At low signal diodes are square-law detectors, quadrupling output for
>>> every doubling in signal voltage.
>>>
>>>> The coupling to a crystal
>>>> earpiece (generally capacitive, but highly reactive load) is
>>>> gonna make quite things weird, by pulling the resonant frequency
>>>> around a lot, dependent on the audio signal...
>>>>
>>>> I should pull out my old xtal earpieces and measure the capacitance.
>>>> I suspect they'd detune a high-Q front end quite a bit, and that
>>>> really calls into question the use of Q to limit bandwidth.
>>>
>>> These guys' coupling transformers ought to transform (lower) the
>>> effective capacitance of any earphone. And any residual capacitance
>>> is simply compensated by re-tuning, anyhow.
>>
>> Yes, but that capacitance is only coupled to the antenna during
>> half-cycles of the audio, while the diode is conducting. So you
>> have two frequencies being tuned. While the diode is off, the
>> alternate frequency is the one which will turn it back on again
>> and slew the tuned frequency to the one you hear.
>>
>> That would explain a lot of what I recall hearing in my crystal
>> earpiece, anyhow; effectively audio intermodulation from adjacent
>> stations.
>
> That's always a danger in a crowded band, yes.
>
>> I guess that's why the Benny is useful; not for the reason he
>> describes, but to make the load appear more resistive.
>>
>> Interesting stuff.
>>
>>> (*) Hey, I just scanned the AM band and the years-standing RFI is gone!!
>>
>> Perhaps you replaced a bit of equipment that had a crappy wall wart?
>> Or a neighbour did!
>
> Not me, it was far too powerful, and stronger outside than inside. I
> suspect an aging line and pole replacement program in progress likely
> removed a HV leaker, somewhere in the neighborhood.
>
> RFI was so bad I hadn't bothered checking the AM band in perhaps a year or
> two--it had been like listening to a Tesla coil or an EDM machine.
>
>> Clifford Heath.
>
> Cheers,
> James Arthur
>
A place I worked at had a hash in the AM band, I walked around with my
am radio and traced it to a power pole about 35ft from our building.
We called the power company and told them they had an arcing power pole
at the corner of...
They responded immediately and by the end of the day our noise was
gone. Looking back saying the pole was arcing was maybe just a little
over kill, but it sure got action.
Mikek
---
This email has been checked for viruses by Avast antivirus software.
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| From | dagmargoodboat@yahoo.com |
|---|---|
| Date | 2017-04-03 14:12 -0700 |
| Message-ID | <5dca946f-79a5-4b18-898b-e47e133d74c5@googlegroups.com> |
| In reply to | #454847 |
On Sunday, April 2, 2017 at 10:22:37 PM UTC-4, amdx wrote: > On 4/2/2017 8:39 PM, dagmargoodboat@yahoo.com wrote: > > On Sunday, April 2, 2017 at 6:48:13 PM UTC-4, Clifford Heath wrote: > >> On 03/04/17 01:12, dagmargoodboat@yahoo.com wrote: > >>> (*) Hey, I just scanned the AM band and the years-standing RFI is gone!! > >> > >> Perhaps you replaced a bit of equipment that had a crappy wall wart? > >> Or a neighbour did! > > > > Not me, it was far too powerful, and stronger outside than inside. I > > suspect an aging line and pole replacement program in progress likely > > removed a HV leaker, somewhere in the neighborhood. > > > > RFI was so bad I hadn't bothered checking the AM band in perhaps a year or > > two--it had been like listening to a Tesla coil or an EDM machine. > > > > > A place I worked at had a hash in the AM band, I walked around with my > am radio and traced it to a power pole about 35ft from our building. I walked around outside a bit with an AM radio when we were having the RFI, but it was everywhere--I couldn't get a bearing on it, other than it was on the powerlines. > We called the power company and told them they had an arcing power pole > at the corner of... I probably should've done that. We have some hams in the area; I'm surprised none of them complained. Until yesterday I'd assumed it was one of my neighbors arc-welding 24/7, or trying to reanimate Frankenstein perhaps. > They responded immediately and by the end of the day our noise was > gone. Looking back saying the pole was arcing was maybe just a little > over kill, but it sure got action. Nice work, Sherlock! Cheers, James Arthur
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-03-27 23:25 -0400 |
| Message-ID | <obckt9$b1f$1@dont-email.me> |
| In reply to | #453929 |
On 3/27/2017 7:16 PM, Clifford Heath wrote: > On 27/03/17 23:25, amdx wrote: >> On 3/27/2017 6:57 AM, Tauno Voipio wrote: >>> Joerg, you seem not understand the innermost sense of the crystal- >>> radio people. They are closely related to audiophools, and it is >>> quite impossible to use sensible technical argumentation here. >> >> I don't get that at all, can you back that up with any facts? > > ~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? > More voltage does not create better audio. Your numbers are meaningless because a coil is not a radio. Why don't you learn about the actual topic rather than just trying to rain on other's parade? Anyone can throw rocks. -- Rick C
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| From | upsidedown@downunder.com |
|---|---|
| Date | 2017-03-28 12:58 +0300 |
| Message-ID | <uockdctr2jj82s2e2qjsoih25g035ln8gn@4ax.com> |
| In reply to | #453929 |
On Tue, 28 Mar 2017 10:16:48 +1100, Clifford Heath <no.spam@please.net> wrote: >On 27/03/17 23:25, amdx wrote: >> On 3/27/2017 6:57 AM, Tauno Voipio wrote: >>> Joerg, you seem not understand the innermost sense of the crystal- >>> radio people. They are closely related to audiophools, and it is >>> quite impossible to use sensible technical argumentation here. >> >> I don't get that at all, can you back that up with any facts? > >~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500? >More voltage does not create better audio. That is the unloaded Q (Qu). The loaded Q (Ql) determines the bandwidth, when a load (such as an amplifier stage or headphones) take out energy from the resonator.
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| From | Joerg <news@analogconsultants.com> |
|---|---|
| Date | 2017-03-27 07:52 -0700 |
| Message-ID | <ejsn9tF9rd5U1@mid.individual.net> |
| In reply to | #453859 |
On 2017-03-27 04:57, Tauno Voipio wrote: > On 26.3.17 17:35, Joerg wrote: >> On 2017-03-25 18:39, rickman wrote: >>> On 3/25/2017 3:30 PM, Joerg wrote: >>>> On 2017-03-25 10:49, rickman wrote: [...] >>>> >>>>> I found it very illuminating his tests with the variable capacitors. >>>>> Even parts like bushings were found to make a difference. >>>>> >>>> >>>> I remember that from my ham radio days. Dirty or oxidized rotor >>>> contacts >>>> .... phssssst ... PHUT ... *BANG* and worst case that could take the >>>> tubes into the abyss along with it. I also spent part of a Wenol >>>> polishing paste tube keeping the final Pi-filter inductor shiny so it >>>> wouldn't heat up too badly and unsolder a connection to it (which could >>>> also result in a loud bang). >>>> >>>> BTW, while such high Q isn't all that useful in practice if you ever >>>> needed that there are simpler means to achieve it. An old method is the >>>> "Q-multiplier". In essence the resonance circuit sits inside an >>>> amplifier stage that is deliberately pulled very close to oscillation. >>>> That shrinks the bandwidth big time. >>> >>> How do you accomplish that without an amplifier? You did notice the >>> site is all about *crystal* radios, right? >>> >> >> You need an amplifier for that. If you want to you can make an >> energy-harvesting one, sans battery. I mentioned this method purely as a >> hint, in case anyone ever needs high Q without making fancy large coils >> and babying them. > > > Joerg, you seem not understand the innermost sense of the crystal- > radio people. They are closely related to audiophools, and it is > quite impossible to use sensible technical argumentation here. > I know :-) However, AFAIK Rick is a guy working in digital electronics. > The question of best MF band coils has been solved already in the > 1930's: A honeycomb coil wound with Litz wire (gloves on). The > canonical fixing / insulating material is beeswax. > Only when mounted on a polished mohagony slab of wood, with the user wearing Sundays's best and a bow tie :-) BTW, I have a Loewe radio with the 3NF type. That is probably the first true integrated circuit from 90 years ago because it contained multiple tube sections, capacitors and resistors. http://www.electricstuff.co.uk/loewe.html -- Regards, Joerg http://www.analogconsultants.com/
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