A quick Google search showed a few available for anywhere between $15K to $25K. The pictures look awesome, but it's a heavy beast and needs some substantial guying. One place suggested that "abandone
I have a great deal of respect for N6BV's HFTA (the improved successor to YT) and the rather sophisticated ray analysis that went into it, but I think it may be prudent to be a bit careful how rigoro
HFTA clearly shows that signals can be refracted over sharp terrain features to bend closer to the horizon (sometimes significantly so) than would otherwise occur based upon the actual antenna height
"Diffraction is reciprocal, regardless of asymmetries in the terrain." HFTA would seem to suggest otherwise. I generated four arbitrary terrain profile files and fed them into HFTA last evening. Each
I don't mean to be dense (although it is a distinct possibility that I am) and I am most definitely not trying to be contentious, but if signal strengths versus takeoff angle are at least partially a
Rick, I don't see how your 2-port S-parameter example is analogous at all. If anything, a directional coupler might be a closer analogy to this discussion. Also, I know that reciprocity does not requ
Unless I'm using the term incorrectly (certainly a possibility), a directional coupler routes signals leaving Port A to Port B, whereas signals leaving Port B in the reverse direction end up at Port
I don't think it works that way. We're not talking diffraction through a prism here at all. A prism is a uniform medium that refracts a wave front uniformly. Edge diffraction is a different mechanism
In the case of light, only a small portion of the light impinges on the knife edge (from either direction). We're not talking about yagi antennas in free space with lots of capture area and nothing i
Hi, Rick. I stand corrected on directional couplers versus circulators. Thanks. No, I'm not implying that transformers are non-symmetrical. It simply occurred to me that my suggestion for what might
Yes, the single ray (for the sake of argument) that travels from A to B is monochromatic, but it isn't infinitely thin in terms of it's interaction with surroundings. That single "ray" is energy trav
Ahh ... a very thoughtful and relevant reply. Thanks! I'll respond to your last comment first. Yes, using HFTA to look at an irregular terrain feature from both sides is not representative of what re
More excellent comments. Yes, I've been thinking about all of this in terms of wave theory, which I'm pretty sure is valid for HF ;) But just to clarify, I'm not trying to justify or promote HFTA. It
Mike, thanks again for the reply. Yes, I fully agree with your description of reciprocity below. No argument. In the context of a radio signal traveling both directions between two points, however, t
I should have done more reading. I'm one of those guys who reads a manual enough to make something work to my satisfaction, and then figure I'll learn the rest of it with use. I've read the pdf file
** "One might want to do this in an anechoic chamber (or, at least, on a open field test site sort of place), just to reduce the confusion from multipath effects. What would folks want to see as far
I asked myself that question a dozen times up front, and always got the answer that since diffraction is a function of the radius of curvature of the diffracting surface, if the diffracting surface i
I worked for Motorola Semi (discrete products) for almost 30 years, most of which was as a business manager. The problem with semiconductor manufacturing is that it takes an incredible amount of capi
I have to agree with Jim, N2EA. Add some top loading wires (more short ones is better than fewer long ones) to your existing 32 foot vertical, build an L-network tuner for the base, and make sure you
That's a very cool idea, but I think he'd need a 65 foot vertical or so to make it work with double those values. The author himself suggests that it's pretty hard to come up with values that work at