- 1. Topband: elevated vertical matching (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Mon, 13 Dec 2004 21:20:51 -0700
- Steve, The radiation resistance of your balloon vertical will be 36 ohms. By the time you add in ground losses you will be up to around 50 ohms. I would just feed it at the base and tweak the length
- /archives//html/Topband/2004-12/msg00174.html (7,085 bytes)
- 2. Topband: 4-square phasing (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Mon, 13 Dec 2004 21:28:28 -0700
- Ron, if I have it figured correctly the 3/4 wavelength lines will cause the two extra elements to lag by 180 degrees. You can fix this by doing one of these: 1) adding 180 degrees of line to the two
- /archives//html/Topband/2004-12/msg00175.html (6,950 bytes)
- 3. Topband: 5BTV on 160m (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Mon, 13 Dec 2004 21:39:01 -0700
- To put a 5BTV on 160M see my AntenneX article in the free section. Or, order a top hat from DX Engineering (similar to the Nantenna top hat- they closed up shop). Or, for a BIG 38' vertical see the l
- /archives//html/Topband/2004-12/msg00178.html (6,450 bytes)
- 4. Re: Topband: 4-square phasing (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Tue, 14 Dec 2004 07:05:02 -0700
- Ron, that's right. It would be best to limit the phasing line lengths to 270 rather than 450 degrees. With changes in frequency the phase error will change faster with a longer line. If no balun or o
- /archives//html/Topband/2004-12/msg00181.html (9,139 bytes)
- 5. Re: Topband: elevated vertical matching (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Tue, 14 Dec 2004 07:18:47 -0700
- Brian, after replying to your posting I began to think you had elevated radials and not a grounded connection. So you have the antenna designed so that it is resonant and the feedline shield is conne
- /archives//html/Topband/2004-12/msg00182.html (9,893 bytes)
- 6. Topband: new Antenna (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Mon, 27 Dec 2004 18:28:15 -0700
- Warren, I thought I had better really simulate the flagpole rather than just dismiss it out of hand. Here are some possibilities: 1) wire from the top of 35' flag pole to the tower, at the 35' level.
- /archives//html/Topband/2004-12/msg00329.html (8,320 bytes)
- 7. [TowerTalk] Re: Topband: New Antenna (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Sun, 26 Dec 2004 17:49:55 -0700
- Warren, this looks like a good start. Are the elements isolated on the 4-40? I am assuming that they are and ran a quick simulation that shows the shunt feed working well at about the 50' level. If y
- /archives//html/Topband/2004-12/msg00346.html (9,887 bytes)
- 8. [TowerTalk] More: Topband: New Antenna (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Sun, 26 Dec 2004 19:38:56 -0700
- Warren, I thought I had better really the flagpole rather than just dismiss it out of hand. Here are some possibilities: 1) wire from the top of 35' flag pole to the tower, at the 35' level. Rr = 7 o
- /archives//html/Topband/2004-12/msg00347.html (10,936 bytes)
- 9. [TowerTalk] Even more: Topband: New Antenna (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Sun, 26 Dec 2004 19:43:48 -0700
- -- Original Message -- From: DAVID CUTHBERT<mailto:DAVIDNNAN@MSN.COM> To: towertalk@contesting.com<mailto:towertalk@contesting.com> ; topband@contesting.com<mailto:topband@contesting.com> ; WarrenWol
- /archives//html/Topband/2004-12/msg00348.html (11,430 bytes)
- 10. [TowerTalk] Re: Even more: Topband: New Antenna (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Mon, 27 Dec 2004 07:13:29 -0700
- -- Original Message -- From: DAVID CUTHBERT<mailto:DAVIDNNAN@MSN.COM> To: towertalk@contesting.com<mailto:towertalk@contesting.com> ; topband@contesting.com<mailto:topband@contesting.com> ; WarrenWol
- /archives//html/Topband/2004-12/msg00349.html (11,925 bytes)
- 11. Topband: coax cap loss (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Mon, 3 Jan 2005 21:52:54 -0700
- Let us look at the loss of a short, open-ended, lossy transmission line stub by examining the energy in the system. I will ignore dielectric loss for now and look at only conductor loss. The conducto
- /archives//html/Topband/2005-01/msg00047.html (7,867 bytes)
- 12. Topband: wideband inv-L (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Tue, 4 Jan 2005 21:29:32 -0700
- We are confining our design space to an inverted-L at this time. I did manage to achieve 200 kHz (2:1 VSWR) in simulation for a 45 foot tall inverted-L having a ground loss of 4 ohms. I can fire up a
- /archives//html/Topband/2005-01/msg00053.html (7,782 bytes)
- 13. Topband: vert lighning protection (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Fri, 7 Jan 2005 06:50:55 -0700
- Phil, It becomes a contest between the fast and repeatable arc in vacuum and the slow and not so repeatable arc across the spark gap. Only one spark gap will fire of the three. The gap should be set
- /archives//html/Topband/2005-01/msg00083.html (7,332 bytes)
- 14. Topband: vertical lightning protection (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Sat, 8 Jan 2005 11:08:38 -0700
- Phil, I modeled your antenna, and if I did it correctly, the 350 uH lighting shunt inductor value can be substantially reduced. Even 35 uH looks good. This would allow 10X the lightning induced di/dt
- /archives//html/Topband/2005-01/msg00136.html (7,908 bytes)
- 15. Topband: model of Phil's tower (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Sun, 9 Jan 2005 10:30:11 -0700
- I have a model of Phil's 199' tower completed. If anyone wants a brief word document on it, or the NEC file, please email me. 73. Dave WX7G _______________________________________________ Topband mai
- /archives//html/Topband/2005-01/msg00153.html (6,266 bytes)
- 16. Topband: Omega-match (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Thu, 13 Jan 2005 06:50:54 -0700
- Andre, Looking at the picture of the burned coax I think I see the problem. It may not be a capacitor current issue but a capacitor voltage issue. It appears that the ends arced. This will take very
- /archives//html/Topband/2005-01/msg00174.html (8,018 bytes)
- 17. Topband: T-antenna (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Wed, 26 Jan 2005 07:10:30 -0700
- Jeff, the first antenna has a radiation resistance of 10 ohms while the flat top is 8 ohms. What I don't know is what the equivalent ground loss resistance is. I guesstimate 25 ohms. If so, the diffe
- /archives//html/Topband/2005-01/msg00294.html (6,594 bytes)
- 18. Topband: HF2V question (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Wed, 2 Feb 2005 19:00:41 -0700
- I have questions about the Butternut HF-2V vertical. Perhaps some of you have answers. 1) The 80 meter door knob capacitor is 250 pF? Or? 2) The 160 meter door knob capacitor is 300 pF? Or? 3) Dimens
- /archives//html/Topband/2005-02/msg00052.html (7,069 bytes)
- 19. Topband: HF2V update (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Thu, 3 Feb 2005 21:23:08 -0700
- Thanks to all of you who sent me valuable information on the HFV2. I have the 160/80/40 meter model working and the coil losses dialed in. I am beginning to like this antenna. This is preliminary but
- /archives//html/Topband/2005-02/msg00061.html (7,194 bytes)
- 20. Re: Topband: Automatic Switching on 80/160 Vertical (score: 1)
- Author: "DAVID CUTHBERT" <DAVIDNNAN@MSN.COM>
- Date: Wed, 2 Mar 2005 20:08:06 -0700
- You could use a complex trap like Butternut uses (which would have higher efficiency with a coil, rather than a distributed inductor like a linear loading stub), but I'd be more inclined to just use
- /archives//html/Topband/2005-03/msg00016.html (7,997 bytes)
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