Carl, you pretty much avoided Steve's question. What rotator failure mode is minimized by having two thrust bearings above the rotator? Can you give any examples of your YCCC buddies that would back
Possibly you should reread my posting ... A plate (positioned between the rotator and the top thrust bearing) with a hole (but without a thrust bearing mounted on it) positions the mast laterally jus
Tell them there is also an ANSI spec that prohibits voids in the galvanizing for structural members. Ask them to show you that spec and convince you they complied with it. The only one I found online
Assuming these are legal copies, the price is right .... http://tinyurl.com/2xqtbz* *Dave AB7E* * _______________________________________________ _______________________________________________ Tower
Could you guys maybe have it reversed? Every time I've modeled an Inverted-L with EZNEC the directivity is in favor of the direction AWAY from the top loading wire. The only exception I've found seem
Here's the very first sentence on the web page where you signed up: "TowerTalk is for discussion of tower and HF antenna construction topics." My guess is that "TowerTalk" was an easier mouthful than
This is the kind of bad information that just never seems to die. A tuner ... ANY tuner .... simply tries to provide a proper impedance transformation between the antenna (or combination of antenna a
Yes, I think that is exactly the case. I've both modeled and used (Field Day) center fed non-resonant dipoles as well as off-center fed dipoles, and the impedance effects represent the major differen
Well, he did say "less the coax and tuner IR losses", and I assume he was including coax dielectric losses in that qualifier. Other than whatever minor IR losses there may be in the antenna itself,
Check out this "safety belt" ... http://youtube.com/watch?v=2ZJz6qLI-Fo Dave AB7E _______________________________________________ _______________________________________________ TowerTalk mailing lis
I just realized someone might think that I was the "Dave" on the tower in the video. Definitely not. Dave AB7E _______________________________________________ ________________________________________
HFTA uses a very simple text format for the terrain files. It's simply two spaced columns of numbers like this: 0 h0 d1 h1 d2 h2 d3 h3 etc, where d# is distance from the antenna and h# is the elevati
A couple of other sites with a large selection of metal products (copper, brass, aluminum) are: www.speedymetals.com www.onlinemetals.com Both sell online in small quantities. 73, Dave AB7E Mark Beck
I assume you mean the top end of the copper clad steel ground rod shouldn't be embedded in the concrete, and that is true. But if he buries the Cadweld joint (wire to ground rod) in the dirt below th
I'm firmly in the camp that says exploding foundations are a myth. I've spent hours and hours searching the internet and haven't been able to find a single documented case of a grounded tower foundat
Hi, Jim. I think we mostly agree here. You make a good devil's advocate, though ;) Regarding copper corrosion, if the ground environment was as extreme as you say, my guess is that any ground rods (c
Hi, Gary. Yes, I agree. I didn't mean to say that concrete cannot explode. It certainly can, and non-uniform heat accomplishes the task quite well. I just don't believe that concrete is **more likely
The only problem with that is that the tower base already represents a very low impedance conductor embedded in the concrete. It is THE lowest impedance conductor in the system. In the case of many t
I think this is the official IRC requirement for a "concrete encased electrode". It always seemed kind of marginal to me, but this is minimum spec: "An electrode encased by at least 2 inches of concr
Jim, If I understand you correctly, there was a large shunt path to ground around the foundation (the 4 straps). Yet the lighting still apparently entered the foundation and generated cracks when it