Re: long antenna

From	gilber34 <fafa@invalid.com>
Newsgroups	sci.physics
Subject	Re: long antenna
Date	2015-11-18 16:57 -0600
Organization	Aioe.org NNTP Server
Message-ID	<n2ivpn$gh9$1@speranza.aioe.org> (permalink)
References	<d82a6d99-39d1-4eb7-9aa0-4ed38641537a@googlegroups.com> <n2fsm5$ms8$1@speranza.aioe.org> <4736856.kWDMch3Bm0@PointedEars.de>

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On 11/18/2015 3:56 PM, Thomas 'PointedEars' Lahn wrote:
> Odd Bodkin wrote:
>
>> On 11/17/2015 12:42 PM, RichD wrote:
>>> During my workout yesterday, I attached a 3 meter
>>> extension to the earphone cord of my radio, as I
>>> wanted to place it at a distance.
>>> The cord is the antenna.
>>>
>>> I was indoors, where the reception is usually crummy.
>>> I figured the longer line should improve performance,
>>> right?  No!  The reception was barely decipherable.
>>>
>>> Can anyone explain the physics here?
>>
>> Yeah, it's pretty simple. The earphone is attached to an OUTPUT of the
>> radio. The only valuable place to stick an antenna is on an INPUT to the
>> radio.
>
> Wrong.
>
>> Signals-->||-->Tuner-->Amplifier-->Analog driver-->||-->Earphones
>>              <-----------  Radio  ------------------->
>>
>> See where the antenna goes?
>
> Not only is your answer wrong, you also missed the point of the question.
>
> As the OP indicated, earphone (also: headphone) cords contain wires which
> can serve as antennas.

.....well, they do connect to the Head which serves as the big resonae 
cavity Antenna. a large round semi conductive salt vat on your sholders, 
full of liquid up in the air.


  [They certainly do with smartphones (from where I
> know the technology): Once you have plugged the headphones into the
> smartphone, you can start a radio app to tune in to FM (frequency
> modulation) radio channels (*without an Internet connection*). [0]
> It stands to reason to use the same technology elsewhere.]
>
> How does radio, how does an antenna work?  Radio is based on the
> transmission and reception of radio waves carrying information piggybacked
> on them through modulation of them.

no piggies were harmed...


> Therefore, the
> longer line does _not_ improve reception quality of a particular radio
> channel (its station transmitting at a particular frequency) to begin with.

that is, in general, a wrong statement.  larger capture area means more 
signal power.


> I also think that the longer the line the more likely that there is
> interference, i.e. alternating, partially canceling electrical currents
> induced at different points of the cable as the (peak of the) radio waves
> can hit the cable at those points at different times, and interference from
> other sources.

they dont "hit" the cable.



> Finally, electrical resistance of a conductor R = ρl∕A,
> where ρ is the material-dependent electrical resistivity and A is the cross-
> sectional area, is proportional to the length l of the conductor [8], so the
> signal that reaches the tuner should become weaker as the cable length
> increases.

wrong.  (match the impeadance, Hint: it is a complex term. lots of free 
programs out there on antenna design if you are interested.)

>
> However, I understand that there are also traveling wave antennae that are
> nonresonant, like random wire for receiving shortwave radio. [9]  So it
> appears to depend on the frequencies that one wants to receive.  I would
> like someone with experience in radio technology to add their expertise
> here.  And please, CMIIW.
>
>
> PointedEars

depends upon what frequency band you are looking at.
FM - you usally will get blasted out by high power stations, over 
loading your very cheap chinese receiver.

Thread

long antenna RichD <r_delaney2001@yahoo.com> - 2015-11-17 10:42 -0800
  Re: long antenna Odd Bodkin <bodkinodd@gmail.com> - 2015-11-17 12:46 -0600
    Re: long antenna Poutnik <poutnik4nntp@gmail.com> - 2015-11-17 20:10 +0100
    Re: long antenna jimp@specsol.spam.sux.com - 2015-11-17 20:28 +0000
      Re: long antenna benj <nobody@gmail.com> - 2015-11-17 16:59 -0500
    Re: long antenna Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-11-18 22:56 +0100
      Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-18 16:57 -0600
        Re: long antenna jimp@specsol.spam.sux.com - 2015-11-18 23:15 +0000
          Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-18 20:42 -0600
            Re: long antenna jimp@specsol.spam.sux.com - 2015-11-19 05:29 +0000
              Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-19 08:54 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-19 18:44 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-22 15:32 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-22 23:16 +0000
            Re: long antenna HVAC <mr.hvac@gmail.com> - 2015-11-19 06:59 -0800
              Re: long antenna benj <none@gmail.com> - 2015-11-19 20:02 -0500
      Re: long antenna benj <none@gmail.com> - 2015-11-19 01:36 -0500
  Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-17 13:28 -0600
  Re: long antenna "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-11-17 14:04 -0800
    Re: long antenna jimp@specsol.spam.sux.com - 2015-11-17 22:35 +0000
      Re: long antenna benj <nobody@gmail.com> - 2015-11-17 19:28 -0500
        Re: long antenna Timo <timo@physics.uq.edu.au> - 2015-11-17 17:18 -0800
          Re: long antenna RichD <r_delaney2001@yahoo.com> - 2015-11-24 11:39 -0800
            Re: long antenna benj <none@gmail.com> - 2015-11-24 15:12 -0500
              Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-26 09:21 -0600
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-26 10:05 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-26 20:05 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-26 18:39 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-27 01:46 +0000
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-26 19:55 +0000
            Re: long antenna jimp@specsol.spam.sux.com - 2015-11-24 20:04 +0000
              Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-24 16:33 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-24 22:58 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-26 09:11 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-26 19:42 +0000
                Re: long antenna "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2015-11-26 11:57 -0800
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-26 14:52 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-26 21:12 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-26 18:58 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-27 01:37 +0000
                Re: long antenna benj <none@gmail.com> - 2015-11-26 23:45 -0500
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-27 01:01 -0600
                Re: long antenna "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2015-11-26 23:31 -0800
                Re: long antenna benj <nobody@gmail.com> - 2015-11-27 11:34 -0500
                Re: long antenna "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2015-11-27 09:58 -0800
                Re: long antenna benj <nobody@gmail.com> - 2015-11-27 11:46 -0500
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-28 16:42 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-28 22:58 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-30 07:46 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-30 19:01 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-30 14:12 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-30 20:43 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-30 17:41 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-12-01 00:15 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-30 20:23 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-12-01 06:21 +0000
                Re: long antenna benj <none@gmail.com> - 2015-11-30 15:22 -0500
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-30 20:48 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-30 17:16 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-30 23:52 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-30 19:59 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-12-01 02:16 +0000
                Re: long antenna benj <none@gmail.com> - 2015-11-30 19:20 -0500
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-27 18:53 +0000
              Re: long antenna benj <none@gmail.com> - 2015-11-25 00:08 -0500
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-25 06:13 +0000
  Re: long antenna "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-11-18 16:25 -0800
  Re: long antenna "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-11-19 16:08 -0800
    Re: long antenna jimp@specsol.spam.sux.com - 2015-11-20 00:40 +0000
      Re: long antenna "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-11-20 15:51 -0800
        Re: long antenna jimp@specsol.spam.sux.com - 2015-11-21 00:34 +0000
          Re: long antenna jmfbahciv <See.above@aol.com> - 2015-11-21 14:37 +0000
            Re: long antenna jimp@specsol.spam.sux.com - 2015-11-21 19:32 +0000
              Re: long antenna jmfbahciv <See.above@aol.com> - 2015-11-22 14:50 +0000
                Re: long antenna "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-11-22 11:27 -0800
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-22 19:44 +0000
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-22 19:40 +0000
                Re: long antenna jmfbahciv <See.above@aol.com> - 2015-11-23 14:13 +0000
                Re: long antenna benj <none@gmail.com> - 2015-11-23 13:00 -0500
                Re: long antenna jmfbahciv <See.above@aol.com> - 2015-11-24 13:20 +0000
                Re: long antenna benj <none@gmail.com> - 2015-11-24 13:40 -0500
                Re: long antenna jmfbahciv <See.above@aol.com> - 2015-11-25 13:44 +0000
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-23 18:47 +0000
                Re: long antenna jmfbahciv <See.above@aol.com> - 2015-11-24 13:20 +0000
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-24 19:49 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-24 16:36 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-24 23:00 +0000
                Re: long antenna gilber34 <fafa@invalid.com> - 2015-11-26 16:17 -0600
                Re: long antenna jimp@specsol.spam.sux.com - 2015-11-26 23:35 +0000
        Re: long antenna benj <none@gmail.com> - 2015-11-20 20:58 -0500
    Re: long antenna benj <none@gmail.com> - 2015-11-19 20:09 -0500
  Re: long antenna "nuny@bid.nes" <Alien8752@gmail.com> - 2015-11-24 12:51 -0800
    Re: long antenna benj <none@gmail.com> - 2015-11-25 00:01 -0500
  Re: long antenna "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-11-25 15:36 -0800
    Re: long antenna jimp@specsol.spam.sux.com - 2015-11-25 23:51 +0000

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