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Total 189 documents matching your query.

41. Re: Topband: verticals and radials and such (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Fri, 11 Dec 2009 10:13:24 -0700
NCJ radial article: The NCJ article included far-field losses and that is what made the verticals seem rather inefficient with even a fine ground system. Previous articles and research have focused o
/archives//html/Topband/2009-12/msg00125.html (7,460 bytes)

42. Re: Topband: 160 Antenna Struggles (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Mon, 21 Dec 2009 08:34:16 -0700
Rip, welcome to Topband. I ran an EZNEC model of your antenna. Sloping the top wire downward and the radials upward as you have reduces the effective vertical length thereby reducing the radiation re
/archives//html/Topband/2009-12/msg00232.html (9,117 bytes)

43. Re: Topband: Radial requirements for 1/2 wave vertical? (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Fri, 19 Feb 2010 11:01:16 -0700
Quarterwave & Halfwave verticals: Theory and simulation say that a halfwave vertical will work almost as well with a ground rod as with a good radial system. My tests at 20 meters between a halfwave
/archives//html/Topband/2010-02/msg00169.html (8,512 bytes)

44. Re: Topband: 160M Transcievers (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Fri, 2 Apr 2010 10:44:58 -0600
Dennis, I had been using less than top tier receivers on top band so I can't speak for the best of the Japanese or Ten Tec. I have used a Kenwood TS-570 with 200 Hz crystal filter, a Yaesu FT-857 wit
/archives//html/Topband/2010-04/msg00013.html (7,502 bytes)

45. Re: Topband: Sunrise enhancement on 160? (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Thu, 15 Apr 2010 07:32:28 -0600
Sunrise and sunset enhancement applies to both ends of the RF link and not just at the 'listener.' I believe ON4UN chose used wording for that sentence. Dave WX7G ____________________________________
/archives//html/Topband/2010-04/msg00070.html (7,484 bytes)

46. Re: Topband: spacers for ladder line (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Tue, 11 May 2010 07:01:29 -0600
Plumbing PVC works and is self-extinguishing. Hobby stores stock smaller diameter plastic rod. I have built light weight open line using double stick foam tape with the wires sandwiched in between. D
/archives//html/Topband/2010-05/msg00028.html (6,992 bytes)

47. Re: Topband: protect my transmitter from atmospheric discharges (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Thu, 3 Jun 2010 06:51:13 -0600
A quarter wavelength shorted coaxial stub across the feed point provides a DC path to ground and greatly attenuates differential-mode lightning current. Dave WX7G ____________________________________
/archives//html/Topband/2010-06/msg00014.html (7,645 bytes)

48. Re: [TowerTalk] Topband: Estimating RF Choke impedance (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Fri, 30 Jul 2010 20:11:03 -0600
Picture 5 shows the generator connected to the coax inner conductors It should be connected to the coax shields. Dave WX7G _______________________________________________ ____________________________
/archives//html/Topband/2010-07/msg00132.html (9,218 bytes)

49. Re: Topband: Newbie question (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Mon, 23 Aug 2010 06:37:24 -0600
Mark, You might have two issues: The MFJ-259 being overloaded and a broken tuner. a NEC models shows the 80 x 94 foot inverted-L having a feedpoint impedance of 43 +j277 over perfect ground (1.8 MHz)
/archives//html/Topband/2010-08/msg00029.html (10,863 bytes)

50. Re: Topband: Inverted L Question (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Fri, 7 Jan 2011 08:38:48 -0700
Scott, let's compare the radiation resistance of the three antennas at 1.8 MHz. 55' x 82' Inverted-L is 16 ohms 100' x 36' Inverted-L with the 36' wire sloping downward at 45 deg is 28 ohms 100' base
/archives//html/Topband/2011-01/msg00030.html (7,387 bytes)

51. Re: Topband: Window Yes! -penalized in contest ! (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Mon, 7 Feb 2011 06:58:02 -0700
Yes there are repercussions. Some stations will not work a domestic station in the DX Window. If everyone followed this rule no domestic station would operate in the DX Window. It takes two to tango.
/archives//html/Topband/2011-02/msg00068.html (7,722 bytes)

52. Re: Topband: [Topband] DX window for the southern hemisphere (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Fri, 11 Feb 2011 08:25:05 -0700
Dave WX7G _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
/archives//html/Topband/2011-02/msg00095.html (8,916 bytes)

53. Re: Topband: Remote Receivers (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Sat, 12 Feb 2011 09:43:37 -0700
It seems we have a collision of ethical philosphies. As most of us in the US are more familiar with poltical philosophy than basic ethical philosophy I'll define the view of HS0ZIA and Michael in tho
/archives//html/Topband/2011-02/msg00130.html (8,490 bytes)

54. Re: Topband: RX Antenna (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Mon, 21 Feb 2011 21:25:14 -0700
I'm right in the middle of the search for a receive antenna. I tried an MFJ-1025 noise canceler and it works quite well to null out the one dominant local noise source that comes on from time to time
/archives//html/Topband/2011-02/msg00170.html (7,759 bytes)

55. Re: Topband: Need EZNEC file for 1/4 wave 160 vertical with radial system (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Thu, 10 Mar 2011 15:50:14 -0700
Here is how to build a useful NEC-2 model of a ground mounted 160 meter vertical. Place a vertical with four radials 1' over real GND. Use 20 current segments for each of the five wires. Place the RF
/archives//html/Topband/2011-03/msg00041.html (7,516 bytes)

56. Re: Topband: Radials help (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Thu, 10 Nov 2011 07:42:27 -0700
Bare radials will work just fine. You plan to use 16 quarter wavelength radials. If you are using (only) 16 to save on wire or installation labor you might want to install 32 eigth wavelength radials
/archives//html/Topband/2011-11/msg00057.html (8,475 bytes)

57. Re: Topband: Another non-traditional antenna working. (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Wed, 16 Nov 2011 15:08:41 -0700
For short radials make them equal lengths and load using a single coil. _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
/archives//html/Topband/2011-11/msg00123.html (9,494 bytes)

58. Re: Topband: Hi Z antenna coupling (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Sun, 20 Nov 2011 13:34:56 -0700
There is no need to transmit to test your antenna. Received signal strength will do. With skywave antenna measurements there can be significant measurement variability. Multiple measurements like so
/archives//html/Topband/2011-11/msg00176.html (8,275 bytes)

59. Re: Topband: The 16th Stew Perry TopBand DX Challenge (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Mon, 21 Nov 2011 13:43:12 -0700
Brian, you might want to call CQ around 1860 kHz. We will find you. Or call anyone. CW tends to run slower on top hand than on HF contests due to a lower signal-to-noise ratio. ______________________
/archives//html/Topband/2011-11/msg00189.html (8,142 bytes)

60. Re: Topband: Counterpoise very interresting (score: 1)
Author: DAVID CUTHBERT <telegrapher9@gmail.com>
Date: Tue, 22 Nov 2011 08:29:37 -0700
L.B. was a professor of Philosophy and not a degreed engineer. _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
/archives//html/Topband/2011-11/msg00198.html (12,388 bytes)


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