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Total 1524 documents matching your query.

1. Re: [CQ-Contest] Topband: RG-6 connector issues/ rcv array (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Sat, 19 Jan 2008 10:02:49 -0500
Very doubtful unless you have the cable firmly anchored at the ends with no slack or stress relief. It is normally from mechanical tension either during or after installation. Been there, had it hap
/archives//html/Towertalk/2008-01/msg00401.html (9,582 bytes)

2. Re: [CQ-Contest] RG-6 connector issues/ rcv array (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Sat, 19 Jan 2008 09:54:35 -0500
Different problem. That was a rigid jacket. He described flexible cables with foil and woven shields, not solid extruded non-ribbed (unlike Heliax, which is ribbed) shields like those that created p
/archives//html/Towertalk/2008-01/msg00399.html (10,377 bytes)

3. Re: Topband: RX 4 square (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Wed, 22 Aug 2007 14:09:43 -0400
I have, several times and the results were not good. It would also be interesting to see how others who have built arrays weigh in on this. I know ZL3IX and others use active elements. At quiet loca
/archives//html/Towertalk/2007-08/msg00608.html (8,350 bytes)

4. Re: Topband: RX 4 square (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Wed, 22 Aug 2007 10:04:13 -0400
Regarding some comments on the active elements, there are a few corrections that need to be made. If this doesn't pass through on Towertalk I hope someone forwards it. First, someone posted that a si
/archives//html/Towertalk/2007-08/msg00604.html (10,527 bytes)

5. Re: [TowerTalk] Ferrite Balun on a LPDA? (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 22:08:39 -0400
Arne, The Tennadyne log has two hot booms. Each boom is used as a conductor in a balanced transmission line. The elements are attached to those transmission line conductors which also serve as a boo
/archives//html/Towertalk/2007-06/msg00454.html (8,928 bytes)

6. Re: [TowerTalk] Balun question shield leakage (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 21:56:26 -0400
We have to be careful here. The leakage is >60dB but that is in a special standard test fixture at virtually zero spacing to the cable in a closed box. It doesn't mean if we have 1000 watts applied
/archives//html/Towertalk/2007-06/msg00453.html (10,985 bytes)

7. Re: [TowerTalk] Balun question shield leakage (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 21:37:10 -0400
<Snip> That all makes sense Carl, and I certainly don't dispute what you saw, but respectfully this is what gets many of us into trouble in understanding how systems work. Without really measuring a
/archives//html/Towertalk/2007-06/msg00451.html (13,360 bytes)

8. Re: [TowerTalk] Balun question shield leakage (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 20:59:21 -0400
How did you measure yours? Or is this just a gut feeling? _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.
/archives//html/Towertalk/2007-06/msg00448.html (10,128 bytes)

9. Re: [TowerTalk] Balun question shield leakage (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 16:53:03 -0400
"Unlikely" isn't strong enough, it would be impossible. I can buy the cheapest radio shack coax, the type that you can see through the shield to the center dielectric, and it is nearly impossible to
/archives//html/Towertalk/2007-06/msg00434.html (10,341 bytes)

10. Re: [TowerTalk] Ferrite Balun on a LPDA? (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 16:32:57 -0400
Watch how you run the coax. If you use a balun and then tape the coax to the boom (which is hot) you totally defeat the reason for having a balun. If you tape the coax to the boom the balun needs to
/archives//html/Towertalk/2007-06/msg00432.html (8,745 bytes)

11. Re: [TowerTalk] Balun question (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 16:15:58 -0400
I can't imagine the need for multiple turns through a core on six meters. First, stray C can quickly become a problem at VHF...even on low VHF. The core would have to be small and that would mean sm
/archives//html/Towertalk/2007-06/msg00431.html (11,007 bytes)

12. Re: [TowerTalk] Single Point Ground (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 15:44:00 -0400
Any of the modern Heliax cables I have seen are closed cell with the dielectric bonded to the center and shield. The shield is also a solid "pipe", and even if it does leak the water has nowhere to
/archives//html/Towertalk/2007-06/msg00429.html (9,609 bytes)

13. [TowerTalk] Blind tests on antennas (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 15:34:17 -0400
If you want a good test, run it as a blind test> Get yourself a two position switch and ask someone else to connect the coaxes from the two antennas to the switch, and simply number the switch positi
/archives//html/Towertalk/2007-06/msg00427.html (9,400 bytes)

14. Re: [TowerTalk] Balun question (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 07:40:17 -0400
At six meters I'd use a sleeve balun of beads (like 43 material several inches long along the cable) and then tape the cable to the boom after that point. You could simply space the coax an inch or
/archives//html/Towertalk/2007-06/msg00394.html (8,939 bytes)

15. Re: [TowerTalk] step away from steppir, Son (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Thu, 14 Jun 2007 07:15:47 -0400
While we all agree all antennas have losses and bandwidth limits, there isn't much useful in all this subjective hyperbole about traps having "astonishing losses" and "optimization on 14.015MHz will
/archives//html/Towertalk/2007-06/msg00392.html (11,338 bytes)

16. Re: [TowerTalk] Single Point Ground (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Wed, 13 Jun 2007 15:30:37 -0400
My manhole in the yard is in a low spot and has an open bottom with gravel. The conduits all slope down to it. Where they don't do that, like in the island to the building, I drilled drain holes in
/archives//html/Towertalk/2007-06/msg00374.html (9,307 bytes)

17. Re: [TowerTalk] RF Choke or Balun (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Wed, 13 Jun 2007 15:23:35 -0400
That's fine. There are a dozen ways to do it, but that would be OK. _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@c
/archives//html/Towertalk/2007-06/msg00373.html (8,144 bytes)

18. Re: [TowerTalk] step away from stepIR (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Tue, 12 Jun 2007 17:41:42 -0400
I don't think so Jim. If that were the case there would be no F/B and the current would not be binomial. The three element Yagi works so well for F/B because elements have a 1:2:1 current ratio and
/archives//html/Towertalk/2007-06/msg00355.html (9,158 bytes)

19. Re: [TowerTalk] Single Point Ground (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Tue, 12 Jun 2007 13:49:41 -0400
Kent, That's really the only way to do it. Did you look at my entrance for an outbuilding shack? http://www.w8ji.com/contest_station_w8ji.htm 73 Tom _______________________________________________ _
/archives//html/Towertalk/2007-06/msg00347.html (8,420 bytes)

20. Re: [TowerTalk] step away from stepIR (score: 1)
Author: "Tom Rauch" <w8ji@contesting.com>
Date: Tue, 12 Jun 2007 12:02:21 -0400
It does guarantee it, at least within limits we care about. It is impossible to come up with a 50 j0 impedance at the end of ANY length cable with modest losses unless the load is very near 50 j0. f
/archives//html/Towertalk/2007-06/msg00344.html (11,297 bytes)

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