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Total 53 documents matching your query.

21. Re: Topband: [TowerTalk] Unique Short Radial Challenge (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Sat, 20 Oct 2007 10:04:05 -0700
Read this: http://force12inc.com/PCSDAT-002.htm It describes an 80m vertical array overlooking salt water. They used a pair of "gull wing" elevated radials at 8' high. They note that this radial conf
/archives//html/Topband/2007-10/msg00100.html (7,854 bytes)

22. Re: Topband: Flag - Mixed diameter conductors (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Thu, 25 Oct 2007 15:57:59 -0700
Go for it! I need to put one of these up, too. I modeled this in EZNEC+ 5.0.10 with the classic 29' by 14' flag dimensions mounted 2 feet above "average" "real/high accuracy" ground. This showed the
/archives//html/Topband/2007-10/msg00165.html (8,699 bytes)

23. Re: Topband: whats your 2:1 SWR bandwidth on an EWE ? (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Wed, 31 Oct 2007 16:33:08 -0700
As you found, the bandwidth is considerable. As long as you have a good transformer, the match will be very broad, since they look a lot like a terminated, unbalanced open-wire line. EWEs should have
/archives//html/Topband/2007-10/msg00200.html (8,187 bytes)

24. Re: Topband: Temporary Beverage? (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Tue, 06 Nov 2007 15:27:04 -0800
I suspected that the presence of the parallel telephone line and the electric fence would ruin the Beverage pattern, so I ran a few quick models in EZNEC. A 200m Beverage (2m high) alone would have a
/archives//html/Topband/2007-11/msg00025.html (8,508 bytes)

25. Re: Topband: Inverted V shaped like a W (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Wed, 07 Nov 2007 18:29:03 -0800
This will work, but it does represent a compromise. The gain will probably be about 4 dB below the conventional inverted-V with the same center height. The bandwidth will be a lot less (less than hal
/archives//html/Topband/2007-11/msg00031.html (9,715 bytes)

26. Re: Topband: feeding 1/2 wave vertical (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Sat, 10 Nov 2007 16:40:48 -0800
From a quick model in EZNEC, it looks like it shouldn't be too hard to shunt feed a grounded half-wave vertical. The model had a 5 inch diameter tower and the same diameter for the shunt feed wire, s
/archives//html/Topband/2007-11/msg00053.html (8,276 bytes)

27. Re: Topband: Vertical array (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Thu, 13 Dec 2007 10:31:29 -0800
At 10:01 PM 2007-12-12, Lee K7TJR wrote, in part: Are there any data on the arrival angles of stateside signals on 160m? I'm no propagation expert, but when looking at the numbers that are shown in W
/archives//html/Topband/2007-12/msg00111.html (8,307 bytes)

28. Re: Topband: Flags and loops in restricted space (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Sat, 29 Dec 2007 09:35:28 -0800
My EZNEC model shows very little interaction between the two antennas. There is some minor change to the back lobes at low elevations, but this is where the signals are down almost 25 dB from the mai
/archives//html/Topband/2007-12/msg00218.html (7,714 bytes)

29. Topband: WWV Antennas (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Tue, 11 Mar 2008 11:01:28 -0700
In addition to the 9 drooping elevated radials, there are 120 radials on the ground, each 0.412 wavelengths long. See Fig. 11 on page 16 of http://tf.nist.gov/general/pdf/1420.pdf for details. A desc
/archives//html/Topband/2008-03/msg00044.html (8,023 bytes)

30. Re: Topband: Phased staggered beverages (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Sat, 06 Sep 2008 20:59:08 -0700
I haven't done this, but one issue is that with unterminated Beverages, the input impedance is a lot more variable (and usually reactive) and that could make it harder to get the current magnitudes e
/archives//html/Topband/2008-09/msg00019.html (8,876 bytes)

31. Re: Topband: Inverted-L vs T Antenna (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Sun, 05 Oct 2008 17:00:39 -0700
In this situation, the inverted-L should have more high angle, horizontally polarized signals for short haul QSOs, but possibly more absorption in the closely spaced tree trunk and slightly lower gai
/archives//html/Topband/2008-10/msg00031.html (8,311 bytes)

32. Re: Topband: Inverted-L vs T Antenna (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Mon, 06 Oct 2008 11:12:42 -0700
Sure, that should work fine, and will also let you use the T or Inverted-L on other bands. (Although the patterns will get "interesting" on the higher bands.) The remote tuner will probably be slight
/archives//html/Topband/2008-10/msg00036.html (8,002 bytes)

33. Re: Topband: EWE 160m (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Tue, 14 Oct 2008 09:10:26 -0700
Andree, It appears that using the 30 meter length increases the gain by about 4 dB, but decreases the F/B from about 22 dB to about 15 dB on 160m (at a 10 degree takeoff angle). This is with #14 wire
/archives//html/Topband/2008-10/msg00103.html (7,782 bytes)

34. Re: Topband: 160m dipole help wanted (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Mon, 24 Nov 2008 17:09:21 -0800
Even easier than loading coils would be to just bend the ends of a full sized dipole down to fit the space available. You may want to pull the ends away from the towers somewhat, either to the side o
/archives//html/Topband/2008-11/msg00205.html (8,165 bytes)

35. Re: Topband: Inverted U antenna (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Tue, 25 Nov 2008 11:07:57 -0800
This shape will have a lower feedpoint resistance than an inverted L. My quick EZNEC model shows 32 ohms for the U vs 62 ohms for the L, including 5 ohms of ground loss, with the open end 15 feet awa
/archives//html/Topband/2008-11/msg00216.html (8,633 bytes)

36. Re: Topband: EWEs and inductors? (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Fri, 05 Dec 2008 12:52:04 -0800
Hi Neil, The first edition of ON4UN doesn't even mention the ewe. In the third edition (1999), ewes are under Antennas and also Feeding in the index (the ewe text is on page 7-46, with dimensions and
/archives//html/Topband/2008-12/msg00056.html (8,421 bytes)

37. Re: Topband: Vertical short dipole ? (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Sun, 07 Dec 2008 17:20:28 -0800
Fred, I was skeptical that there would be any benefit to the vertical dipole configuration with two 160m mobile whips, but after modeling this, it appears that there is a 3 dB improvement. I modeled
/archives//html/Topband/2008-12/msg00081.html (10,715 bytes)

38. Re: Topband: Vee Beams (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Fri, 12 Dec 2008 12:46:57 -0800
Take a look at http://www.antenna.it/military/vr%2023-f.htm This is a military version of a sloping terminated vee. Although it is rated for 2-30 MHz, it won't have much gain on 160m. If you double t
/archives//html/Topband/2008-12/msg00141.html (8,807 bytes)

39. Re: Topband: Impedance of two wires to ground? (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Wed, 14 Jan 2009 16:29:44 -0800
From the Johnson & Jasik "Antenna Engineering Handbook, 2nd Edition", page 42-9 Differential mode impedance (between conductors): Zo = 276/sqrt(epsilon) * log10 (4h / (d * sqrt(1 + (2h/S)^2))) Common
/archives//html/Topband/2009-01/msg00133.html (8,390 bytes)

40. Re: Topband: Several questions: (score: 1)
Author: Terry Conboy <n6ry@arrl.net>
Date: Tue, 28 Jul 2009 14:14:29 -0700
Dennis, You didn't say how the RFI affects you. Where does it appear? It sounds like your vertical antenna is very close to the shack. Maybe 40 feet or less? If so, you are definitely in the near fie
/archives//html/Topband/2009-07/msg00144.html (11,348 bytes)


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