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References: [ +from:ab7echo@gmail.com: 101 ]

Total 101 documents matching your query.

1. Re: [TowerTalk] Do I need an insulator on the ends of my (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Sat, 27 Jun 2020 12:42:11 -0700
I just tried modeling something like that.  I used 100 foot 100 feet high wire fed at the 25% point at a frequency that would represent a fullwave, but checking the current at the mid point and divid
/archives//html/Towertalk/2020-06/msg00216.html (12,625 bytes)

2. Re: [TowerTalk] Common Mode RF choke on a 50 MHz yagi (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Sun, 28 Jun 2020 15:25:07 -0700
That's a standard quarter wave coaxial choke that has been in antenna books for several decades in one form or other.  I used that technique on a triband quad (with separate feedlines) more than 50 y
/archives//html/Towertalk/2020-06/msg00234.html (8,948 bytes)

3. Re: [TowerTalk] 20m monoband Yagi height (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Tue, 14 Jul 2020 11:28:58 -0700
The answer to your question isn't simple, but HFTA will give you good insight into the problem. 50 feet will give you decent radiation at almost all elevation angles except for the very low ones (les
/archives//html/Towertalk/2020-07/msg00170.html (11,054 bytes)

4. Re: [TowerTalk] Best Way To Clean Copper Ground Wire for Erico Cadweld Connection? (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Fri, 17 Jul 2020 23:09:52 -0700
I'm not sure the tarnish matters much in the first place, especially if the tarnish is copper oxide since copper oxide is one of the key components of Cadweld welding material (copper thermite). _3 C
/archives//html/Towertalk/2020-07/msg00208.html (9,937 bytes)

5. Re: [TowerTalk] Balun for Force 12 6 Element 20 Meter Monobander (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Mon, 20 Jul 2020 19:57:00 -0700
I think K9YC's data on Balun Design common mode chokes would suggest otherwise. Dave   AB7E Balun Design are the Balun of choise IMO Wayne _______________________________________________ ____________
/archives//html/Towertalk/2020-07/msg00234.html (8,521 bytes)

6. Re: [TowerTalk] Balun for Force 12 6 Element 20 Meter Monobander (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Tue, 21 Jul 2020 13:19:18 -0700
When you don't understand what you read, everything is going to sound contradictory and confusing.  Saying things like "it may or may not be useful" and "I'm not going to be better off than just haph
/archives//html/Towertalk/2020-07/msg00262.html (12,128 bytes)

7. Re: [TowerTalk] Buried HF/VHF feedlines (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Sat, 25 Jul 2020 01:02:32 -0700
Heliax is essentially plumbing.  Quite possibly I simply don't understand, but why is water a problem?  How does it penetrate the copper sheath? And if water is a problem, why can't you have a hole i
/archives//html/Towertalk/2020-07/msg00314.html (9,485 bytes)

8. Re: [TowerTalk] Buried HF/VHF feedlines (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Sat, 25 Jul 2020 10:00:19 -0700
I understand all of that.  Water vapor will penetrate the walls of the conduit and condense inside, or as you say, get inside via air flow through the conduit.  But why is that a problem for the Heli
/archives//html/Towertalk/2020-07/msg00318.html (10,362 bytes)

9. Re: [TowerTalk] remote controlled tuners? (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Mon, 3 Aug 2020 11:13:00 -0700
Hi, Jim. Do you plan to use this for transmit, or for receive? I'm no network expert, but if you intend to do this for transmit I don't think you can variably shift the phase AND also at the same tim
/archives//html/Towertalk/2020-08/msg00010.html (9,574 bytes)

10. Re: [TowerTalk] Climbing Harness Recommendations needed (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Wed, 19 Aug 2020 10:42:39 -0700
For a gorilla clip, I strongly recommend one of these aluminum clamps: https://www.rescuetech1.com/iscritrecoveryhooknew.aspx I own three of them.  They are very strong, large enough to clamp onto al
/archives//html/Towertalk/2020-08/msg00128.html (8,266 bytes)

11. [TowerTalk] VSWR Heating in Chokes and Baluns (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Thu, 3 Sep 2020 11:14:23 -0700
Can anyone point me to a technical reference that discusses dielectric heating (not magnetic flux related) due to high VSWR in the ferrite core of a balun or common mode choke? Thanks much, Dave   Ab
/archives//html/Towertalk/2020-09/msg00026.html (7,251 bytes)

12. Re: [TowerTalk] VSWR Heating in Chokes and Baluns (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Thu, 3 Sep 2020 14:52:55 -0700
I've done a BUNCH of Google searching using (among others) the search phrases "dielectric properties of ferrites", "heating effects in ferrites", "VSWR failures of baluns", etc and so far not found a
/archives//html/Towertalk/2020-09/msg00030.html (10,867 bytes)

13. Re: [TowerTalk] VSWR Heating in Chokes and Baluns (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Thu, 3 Sep 2020 19:30:17 -0700
I was referring to a balun with that statement. Dave   AB7E I remember, though, previous discussions here on TowerTalk where more knowledgeable people than either you or I pointed out that damaging c
/archives//html/Towertalk/2020-09/msg00033.html (14,798 bytes)

14. Re: [TowerTalk] VSWR Heating in Chokes and Baluns (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Mon, 7 Sep 2020 10:44:15 -0700
Hi, Hank. Well, I have various very high power resistors, so by using them in various combinations with some large variable capacitors I can generate various VSWR loads.  I can measure the actual R +
/archives//html/Towertalk/2020-09/msg00068.html (13,785 bytes)

15. [TowerTalk] Igniting Cadweld Powder (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Wed, 16 Sep 2020 11:40:26 -0700
The grounding of a tower often involves the use of several welds using Cadweld or similar copper/aluminum thermite.  One of the associated problems is that the Cadweld powder can be tricky to ignite
/archives//html/Towertalk/2020-09/msg00165.html (9,348 bytes)

16. Re: [TowerTalk] Paint Fiberglass antennas? (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Wed, 16 Sep 2020 13:03:08 -0700
I'm no expert, but I suspect boat paint would be a reasonable choice.  Probably depends upon what kind of fiberglass (epoxy or polyester) was used for the antenna. Not sure about northern Illinois, b
/archives//html/Towertalk/2020-09/msg00167.html (8,736 bytes)

17. Re: [TowerTalk] Working with HFTASweep data (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Sat, 3 Oct 2020 11:55:24 -0700
Hi, Randy. If I understand your question correctly, you should be able to highlight the text data, copy, it, and then paste it into Excel with the "text" option selected. If that doesn't work for you
/archives//html/Towertalk/2020-10/msg00012.html (8,055 bytes)

18. Re: [TowerTalk] Greyline Performance antennas (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Fri, 16 Oct 2020 18:24:35 -0700
After reading their web site, I have to say that their claims sound like a lot of unfounded fluff. They claim "lower noise", which is completely vague and physically unlikely for a vertical. They cla
/archives//html/Towertalk/2020-10/msg00124.html (9,857 bytes)

19. Re: [TowerTalk] Greyline Performance antennas (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Sat, 17 Oct 2020 19:20:02 -0700
"Incredible" is the operative word here.  Some of those claims you list defy physics. 73, Dave   AB7E On 10/17/2020 7:13 PM, john@kk9a.com wrote: I have not heard of Greyline until now, the listed sp
/archives//html/Towertalk/2020-10/msg00141.html (9,083 bytes)

20. Re: [TowerTalk] Greyline Performance comments on QRZ (score: 1)
Author: David Gilbert <ab7echo@gmail.com>
Date: Sun, 18 Oct 2020 14:46:05 -0700
Quite interesting. If I understand the reviews correctly, the antenna uses an off the shelf tuner made by a different company? And the choke is made by Palomar?  Really??? 73, Dave   AB7E ___________
/archives//html/Towertalk/2020-10/msg00158.html (7,409 bytes)


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