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Groups > sci.physics > #536554
| From | jimp@specsol.spam.sux.com |
|---|---|
| Newsgroups | sci.physics |
| Subject | Re: long antenna |
| Date | 2015-11-30 20:43 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <i0puic-at8.ln1@mail.specsol.com> (permalink) |
| References | (9 earlier) <n3dala$v0i$1@speranza.aioe.org> <16opic-5al.ln1@mail.specsol.com> <n3hjv2$kku$1@speranza.aioe.org> <s0juic-u98.ln1@mail.specsol.com> <n3iajn$ha2$1@speranza.aioe.org> |
gilber34 <fafa@invalid.com> wrote: > On 11/30/2015 1:01 PM, jimp@specsol.spam.sux.com wrote: >> gilber34 <fafa@invalid.com> wrote: >>> On 11/28/2015 4:58 PM, jimp@specsol.spam.sux.com wrote: >>>> gilber34 <fafa@invalid.com> wrote: >>>>> On 11/27/2015 10:46 AM, benj wrote: >>>>>> On 11/27/2015 02:01 AM, gilber34 wrote: >>>>>>> On 11/26/2015 10:45 PM, benj wrote: >>>>>>>> On 11/26/2015 08:37 PM, jimp@specsol.spam.sux.com wrote: >>>>> >>>>>> >>>>>> perhaps not gamma ray, but you DO know that X-ray parabolic antennas >>>>>> exist, right? >>>>> >>>>> using glancing, paraboioids and hyperboioids, not quite the same as a >>>>> dish. but my point was to counter the over generalization that EM >>>>> frequency being the same. Still waiting on the size of the 60 HZ dish >>>>> for 20 dB gain... >>>> >>>> Pretty large, but the physical size is irrelevant; the gain of a dish >>>> is a function of it's diameter in wavelengths, so the gain of a 3 lambda >>>> 60 Hz dish is the same as the gain of a 3 lambda 60 GHz dish. >>> >>> as usual, WRONG. >> >> Nope. >> >> Then why do antenna books have nomographs of dB gain verssus physical >> size with straight lines for frequency. > > you should stay away from them, they cause you to over-generalize You should look at some and learn something. >> >>> the 60Hz dish would be 17,794,063.6 meters wide or 11,056 miles wide or >>> 100 times the diameter of the Earth. Impossable to build it at all. >> >> Not in space given enough time and money. > > infinite time, infinite money, infinite stupidity, it cannot be built in > space either. (extra credit for why) Electromagnetic theory has nothing to do with structural engineering. >> >>> THE PHYSICAL SIZE IS THE ISSUE ! >> >> Nope. >> >> Physical size only determines the econonomic practicably, not the RF >> characteristics. > > Wrong. In what bands is RF treated as primarly magnetic, treated as EM, > and then treated as partical ? None; you are a babbling idiot. >> >>> (what size waveguide do you feed a 60 Hz dish with ?) >> >> You assume due to your utter ignorance of antennas and RF in general >> that all dishes are fed with waveguide; they are not. It is very >> common to feed dishes in the lower microwave region and below with >> coax. > > answer the question, what size waveguide do you feed a 60Hz dish with ? > (since you say RF scales with everything) You assume due to your utter ignorance of antennas and RF in general that all dishes are fed with waveguide; they are not. It is very common to feed dishes in the lower microwave region and below with coax. While one COULD construt 60 Hz waveguide in space, doing so would be stupid. >> >>> your max surface roughness at 60GHz is what ? >> >> It is perfect because competant people were used to build it and >> irrelevant to the fact that antennas scale in frequency. > > so what is the surface roughness ? use rms It is perfect because competant people were used to build it and irrelevant to the fact that antennas scale in frequency. > and again you are wrong, antennas scale over ranges, not infinities. Nowhere in any electromagnetic theory will you find anything like A < frequency < B. You are an ignorant idiot. >> >>> How much beam taper do you illuminate the edges with to avoid backlobes >>> at 60GHz? which would pick up the 60HZ earth very well. What would the >>> F/B ratio be to pick up a 60Hz craft 1,000,000,000 miles out ? >> >> The same as at 60 GHz. > > Totally wrong, one is easy, the other is impossable. Nope, just not practically economical to build. > > How thick must your dish be to reflect 60Hz ? New flash idiot, the skin effect scales with frequency also. > how much beam taper ? Irrelevant. >> >>>> The only issue with a dish at gamma or X-ray frquencies is that the >>>> dish has to be made of a material that is reflective at those frequencies, >>> >>> which there are not any for a parabolic dish. >> >> Which is irrelevant to the fact that antennas scale in frequency. > > Wrong, because you cannot use a parabolic with gamma, so the do not scale. > wrong, because you over-generalized All the laws of electromagnetics says it scales. The fact that there is no practical material to build one is irrelevant to the theory of electromagnetics. >> >> If you can find a material that is relective at gamma or X-ray frquencies, >> then such a dish will perform just the same as any other dish at any >> other frequency with the same diameter in wavelengths. > > "if" but it dosent, so a parabolic dish will not work, and has no gain. All the laws of electromagnetics says it scales. The fact that there is no practical material to build one is irrelevant to the theory of electromagnetics. > Not scalable. Yep. >> >>> what is the max surface roughness you could have ? (hint: 1/4 lamda and >>> how much is that?) can anybody do that yet ? >>> so you are WRONG again, find the answer in ARRL, not. >> >> The requirements would be the same as any other dish at any other frequency >> with the same diameter in wavelengths. > > more foo-foo. You have not been able to justify your absurd > over-generalization. All the laws of electromagnetics says it scales. > go do that to a bicycle, one can be made at any size and still function... The subject is the laws of electromagnetics. >> >> The thing you are utterly unable to understand is that electromagnetic >> theory of antennas is frequency independant. > > wrong. antennas are resonate material structures only at certian > frequiencys. Apples and oranges and shows an utter lack of understanding of electromagnetic theory. A yagi antenna has a particular size in WAVELENGTHS. That means that if the antenna is described in WAVELENGTHS, it works identically at any frequency. All half wavelength dipoles work identically because their size is described in WAVELENGTHS. >> >> The practical ability to construct a given antenna may change with >> frequency, but the electromagnetic theory does NOT. > > wrong again. > EM theory(s) applies differently to different structures, it is not > one equation governs all. And is driven by boundry conditions, some > scale, some do not. Babbling gibberish. > at times you have to use other means than stright EM to make the > antenna work, like the capacitive match at a single helix antenna > reflector, diameter of Yagi elements. Babbling gibberish. > take the transmitter, receiver transmission path reciprosity, it can be > non linear. EM theory says linear. Babbling gibberish. > here is a link you can study > https://en.wikipedia.org/wiki/Maxwell's_equations And where in there do you see any term that looks like A < freq < B, you babbling idiot? -- Jim Pennino
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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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