- 1. Re: [TenTec] Antenna measurements (score: 1)
- Author: Stuart Rohre <rohre@arlut.utexas.edu>
- Date: Fri, 19 Apr 2013 16:29:37 -0500
- Actually, even back in the day of tests before the FCC, you did not get all that antenna stuff until the Extra Class license. You could miss probably all of it and still pass, since passing was 75 pe
- /archives//html/TenTec/2013-04/msg00196.html (9,951 bytes)
- 2. Re: [TenTec] Antenna measurements (score: 1)
- Author: shristov <shristov@ptt.rs>
- Date: Sat, 20 Apr 2013 00:27:38 +0200
- This is incorrect and misleading. Whenever an AC current flows on a wire, there is an accompanying and inseparable AC electromagnetic field surrounding the wire. And the said AC field propagates in a
- /archives//html/TenTec/2013-04/msg00198.html (9,824 bytes)
- 3. Re: [TenTec] Antenna measurements (score: 1)
- Author: Steve Hunt <steve@karinya.net>
- Date: Sun, 21 Apr 2013 22:14:45 +0100
- That's correct - it's charge acceleration and deceleration which causes radiation. If you take a long wire and terminate it in its characteristic impedance it will radiate - there doesn't need to be
- /archives//html/TenTec/2013-04/msg00215.html (10,722 bytes)
- 4. Re: [TenTec] Antenna measurements (score: 1)
- Author: Ken Brown <ken.d.brown@hawaiiantel.net>
- Date: Sun, 21 Apr 2013 12:38:02 -1000
- That's correct - it's charge acceleration and deceleration which causes radiation. If you take a long wire and terminate it in its characteristic impedance it will radiate - there doesn't need to be
- /archives//html/TenTec/2013-04/msg00217.html (11,590 bytes)
- 5. Re: [TenTec] Antenna measurements (score: 1)
- Author: Stuart Rohre <rohre@arlut.utexas.edu>
- Date: Mon, 22 Apr 2013 15:21:10 -0500
- Sir, I paraphrased almost the exact words of John Kraus, W8JK, in "Antennas" second edition. To be clear, I was referring to a change in RF current when I said "current". Change means any, an acceler
- /archives//html/TenTec/2013-04/msg00236.html (9,700 bytes)
- 6. Re: [TenTec] Antenna measurements (score: 1)
- Author: Stuart Rohre <rohre@arlut.utexas.edu>
- Date: Mon, 22 Apr 2013 16:02:03 -0500
- But any termination, or an open is a scompared to the RF current environment in the wire. _______________________________________________ TenTec mailing list TenTec@contesting.com http://lists.contes
- /archives//html/TenTec/2013-04/msg00237.html (9,993 bytes)
- 7. Re: [TenTec] Antenna measurements (score: 1)
- Author: Steve Hunt <steve@karinya.net>
- Date: Mon, 22 Apr 2013 22:26:22 +0100
- Stuart, Can you give us the exact Kraus quote, or a reference, to see the context in which he made it? "Although a charge moving with uniform velocity along a straight conductor does not radiate, a c
- /archives//html/TenTec/2013-04/msg00240.html (10,347 bytes)
- 8. Re: [TenTec] Antenna measurements (score: 1)
- Author: art N4UC <n4uc@hotmail.com>
- Date: Mon, 22 Apr 2013 21:24:49 -0500
- As my old college fields professor would always say, "Starting with Maxwell's equations..." _______________________________________________ TenTec mailing list TenTec@contesting.com http://lists.cont
- /archives//html/TenTec/2013-04/msg00244.html (11,029 bytes)
- 9. Re: [TenTec] Antenna measurements (score: 1)
- Author: Stuart Rohre <rohre@arlut.utexas.edu>
- Date: Tue, 23 Apr 2013 15:06:20 -0500
- Yes, indeed, start with Maxwell's equations, but you can understand antenna action from the basics in Chapter 2 of John Kraus's "Antennas" 2nd Ed. Not sure how much he changed the book order by the 3
- /archives//html/TenTec/2013-04/msg00249.html (12,904 bytes)
- 10. Re: [TenTec] Antenna measurements (score: 1)
- Author: Steve Hunt <steve@karinya.net>
- Date: Tue, 23 Apr 2013 21:24:04 +0100
- Stuart, As yet, I've been unable to find anything remotely like that in my 3rd edition; but I'll carry on looking :) A simple "test question" for me would be: "does an infinitely long straight wire (
- /archives//html/TenTec/2013-04/msg00250.html (11,305 bytes)
- 11. Re: [TenTec] Antenna measurements (score: 1)
- Author: Stuart Rohre <rohre@arlut.utexas.edu>
- Date: Tue, 23 Apr 2013 15:44:31 -0500
- Yes, that case of an accelerating current would radiate per the acceleration criteria in 2nd Edition of Kraus. One type of current that would be accelerating is a simple harmonic oscillation. The har
- /archives//html/TenTec/2013-04/msg00251.html (11,029 bytes)
- 12. Re: [TenTec] Antenna measurements (score: 1)
- Author: "bcarling@cfl.rr.com" <bcarling@cfl.rr.com>
- Date: Tue, 23 Apr 2013 16:51:29 -0400
- This is getting fairly esoteric. Like... If a tree falls in the forest and nobody is there to listen does it make a sound? Answer: Yes of course it does. Bry Carling http://www.af4k.com http://allthe
- /archives//html/TenTec/2013-04/msg00253.html (8,650 bytes)
- 13. Re: [TenTec] Antenna measurements (score: 1)
- Author: Steve Hunt <steve@karinya.net>
- Date: Tue, 23 Apr 2013 22:07:01 +0100
- This is the concise statement I have in my (very) old course notebook: Static charge -> electric field Moving charge (non-accelerating) -> magnetic field Accelerating or decelerating charge -> EM rad
- /archives//html/TenTec/2013-04/msg00255.html (11,713 bytes)
- 14. Re: [TenTec] Antenna measurements (score: 1)
- Author: Stuart Rohre <rohre@arlut.utexas.edu>
- Date: Tue, 23 Apr 2013 17:11:04 -0500
- A very good summary! Stuart K5KVH _______________________________________________ TenTec mailing list TenTec@contesting.com http://lists.contesting.com/mailman/listinfo/tentec
- /archives//html/TenTec/2013-04/msg00258.html (10,070 bytes)
- 15. Re: [TenTec] Antenna measurements (score: 1)
- Author: Ken Brown <ken.d.brown@hawaiiantel.net>
- Date: Wed, 24 Apr 2013 03:05:23 +0000 (UTC)
- Yes. Maxwell's equations say nothing about how long the conductor is. If there is charge acceleration, which there is if there is an AC current, then there is radiation. ____________________________
- /archives//html/TenTec/2013-04/msg00269.html (9,406 bytes)
- 16. Re: [TenTec] Antenna measurements (score: 1)
- Author: Ken Brown <ken.d.brown@hawaiiantel.net>
- Date: Wed, 24 Apr 2013 03:08:11 +0000 (UTC)
- And any conductor with RF current flowing in it is an antenna, unless there are special conditions to make it not radiate (much) such as in transmission lines and faraday shields. __________________
- /archives//html/TenTec/2013-04/msg00270.html (9,644 bytes)
- 17. Re: [TenTec] Antenna measurements (score: 1)
- Author: Ken Brown <ken.d.brown@hawaiiantel.net>
- Date: Wed, 24 Apr 2013 03:10:14 +0000 (UTC)
- If a charge accelerates in a wire and nobody calls it an antenna, does it radiate. Yes of course it does. _______________________________________________ TenTec mailing list TenTec@contesting.com ht
- /archives//html/TenTec/2013-04/msg00271.html (7,467 bytes)
- 18. Re: [TenTec] Antenna measurements (score: 1)
- Author: Richards <jrichards@k8jhr.com>
- Date: Tue, 23 Apr 2013 23:38:38 -0400
- However, I have seen books like the old ARRL Handbooks start right in with wave theory of the E and H field, and never really say what is the process of radiation, other than it happens from an ante
- /archives//html/TenTec/2013-04/msg00272.html (10,638 bytes)
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