I mentioned before that I thought we should consider a radial system for a quarter wave vertical to be just a counterpoise, and it turns out that a bit of research says that is obvious. That wouldn'
Thanks for the comments, Jim. Well, the reason I don't think a radial system necessarily provides any shielding effect is that there is VERY little difference in either takeoff angle or maximum field
It does not need a radial system of wires to avoid loss. It just needs an alternative path to the earth for near field return currents, and that can be had with a proper counterpoise. The modeling
Thanks, Mike! Yeah, the work you have done over the years with your 4-squares has been amazing. I have been paying attention. ;) As you say, nothing we do can change the effect that the ground has
Jim, I can see where my wording could be interpreted incorrectly since the word "to" has multiple meanings, but that isn't what I said. Read it instead as "alternative to the earth path". That's le
As a system it's the same electrically, but physically and individually I think it's a bit different. A bent leg of a dipole has not very much distributed capacitance and a considerable distributed
K9YC said "Takeoff angle is a stupid concept.". That is hardly true. Focusing ONLY on the gain at maximum takeoff angle may be misleading, but when comparing the same antenna at different heights or
Any thoughts on this text fixture? https://www.youtube.com/watch?v=AyURuo0UEdE Dave AB7E _______________________________________________ _______________________________________________ TowerTalk ma
Lots of great comments in response to my original query on the test fixture ... and how to get the best results from it. It seems to me, though, that for most of us it isn't important that we know wh
That is of course great advice, but in my case almost all of my coax is either on the tower or buried underground. Climbing up and down the tower several times taking measurements along the line (th
Yes ... but I assume that we want to place the CMC as close to a current maximum as we can, so we kind of need to know where that is. Am I wrong about that? 73, Dave AB7E "(the process is useless if
I didn't write the text that you responded to. VE7RF did. Dave AB7E I also use a choke farther down the feedline to prevent it acting as a parasitic element to my 160M vertical. 18 years ago, I ob
Yeah, I assumed one at the feedpoint. I was referring to the situation where you might want to add another one. I still think that should go at a current maximum if possible. Dave AB7E On 1/25/20
As you say, the coax can make significant changes between the impedance at the antenna and what you read at the near end of the coax. Like huge. Here are two methods to deal with that. 1. Use TLW
That's every bit as technically correct as anything I said ... it just requires that you cut a piece of coax to a particular length so it's not quite as versatile. But just as valid. Dave AB7E Joh
I don't know how you came up with that conclusion. Even the cheapest NanoVNAs I'm aware of have the ability to do SOL compensation. Most even come with the loads. If you meant feedline length compe
A possible approach for control lines is using 4/20m current loop modules that are cheap and readily available on Amazon. They are low impedance and relatively insensitive to most noise pickup. The
I recently did an EZNEC analysis of a vertical antenna fed against a square wire mesh instead of radials. Like all radials, the mesh is just a counterpoise for tuning to resonance except that the re
I've thought about using two meshes on the surface of the ground spaced some distance apart. Sweep the frequency while measuring the complex impedance between them. I know for a fact that my rocky h
I've been interested for some time in tracking the arrival angle of DX signals, and in the past I've used the audio output of the two phase locked receivers in my Elecraft K3 fed into a 2-channel osc