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
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
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
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
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 _______________________________________________ ____________
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
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
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
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
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
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
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
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
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 +
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
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
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
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
"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
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 ___________