A Shakespere CB whip in my 66 Corvette which was advervtised for fiberglass cars. It couldnt be heard a mile away with 4W. I added "radials" from the base on the rear deck to the frame on all 4 corne
Hi Don, Then, why do broadcast stations that use vertical towers at approximately a half wavelength, purchase valuable real estate and spend thousands of dollars for the copper to install from 120 to
Tom, I think you are extrapolating one case with a particular radial length to all vertical antenna ground systems. The N6LF radial papers detail his NEC-4 simulations and measurements of vertical an
You likely had an antenna with 1/2 wave of wire spooled up on a short fiberglass rod, which would never behave like a half-wave. You are exactly right. Unfortunately, this myth dies hard. Below is a
length. For want of a better word its image has to be a perfect conductor for the antenna system as a whole to be 100% efficient. The invocation of "image" into efficiency or ground losses shows a mi
Just to be clear, since the discussion drifted to half-wave radiators, my comment above was specific to the modeling of thick v. thin half-wave radiators, including the 180-195 degree radiators of so
To work at its maximum efficiency a vertical needs a real ground system and the image is its fictitious counterpart to isotropic. Im oversimplyfing here so no need to pick nits. Besides being untrue,
Dave... would it be a fair extrapolation to take your last sentence, and draw the conclusion that if adding radials changes feed impedance, then there was actual ground loss in the near field? Or tha
<<But doesn't this merely confirm the notion that the half-wave vertical needs some kind of ground system to work against, and in addition to minimise ground loss when the base of the radiator is in
** All that means is that the elevation peak of the wave as seen in the typical 2D plot increases by .38dB and as expected. It does not say what happens from that peak down to zero elevation which is
We both agree that the .38 db increase is at all elevation angles since the increase in efficiency at the feed doesnt change the pattern shape, just levels. OK ? There you say pattern shape does not
This is where I think the problem is. You say: ** Since the TOA is established at almost ground zero, radials can increase the energy at angles that would otherwise be attenuated. That is incorrect.
I hope Tree and everyone else doesn't mind one measured response to this: In a free society the mere idea of banning people just because we disagree with them goes against our principles of liberty a
Anyone have problems running a KLM antenna with the 4:! balun and elements insulated from the boom (stock KLM config) on a shunt fed tower for 160? I ask because I have a 6 element 10 on the top of m
I am right now using an inverted L which is spaced about 4 feet away from my tower. The vertical leg is about 85 feet. I only have 6 radials at the present time Now here is the question The horizonta
A little different version of this question - is there any general guidance about what to do with pickup on other antennas when transmitting? Shunt the pickup to a dummy load? short? open? something
<<<<I used several short bogs back in the 80's on a small urban lot where their length was about 120'. I got the information on them from John K9DX. The interesting thing was that the bog wire was co
Shielded loops are not shielded, and neither are shielded ground leads or even BOG's. The outside is always the naked antenna, just like a single unshielded conductor. One more additional comment tha
Dielectrics affects/increases capacitance. Question: Has anyone made a study as to how it lowers the frequency of the wire that it is covering?. My thought.... It is probably is a linear capacitance