On Sun, Nov 21, 2010 at 11:05 PM, Garry Shapiro <firstname.lastname@example.org> wrote:
> Aren't there several issues being discussed simultaneously here?
> 1. The question asked was about the "basic" two-wire Beverage using, in
> lieu of a reflection transformer, one wire grounded and the other open,
> to effect a reflection/conversion from balanced to unbalanced to convey
> the far-end signal back to the feed-end. Devoldere points out that,
> while this "works". there is a 2:1 impedance mismatch, which is avoided
> by use of a proper reflection transformer.
> An interesting aspect of using two ports is that a mismatch of either
> mostly degrades F/B ratio. This is seen by tracing the path and phase
> reversals of the reflected components due to mismatch. But the same
> effect can be had with a single feed, since the Beverage is, in either
> case a two-port network.
Actually, Garry, although I failed to make it clear in the original
question, I was inquiring about a two wire beverage with reflection
transformer. I should have explicitly said so. What I was interested in
was the two coax feed system, without the relay circuitry...bias-T, etc.
Tom, W8JI, said the same thing as ON4UN about the two wire, one open and one
grounded, beverage...but more emphatically and colorfully! Despite their
warnings, I have tried it and it does work...although not as well as a
terminated beverage. This was several years ago, in my first days working
DX on 160 and I was delighted with any improvement over the noisy vertical
that I had been using for receiving. I'm not so easily impressed now.
> 2. Misek pointed out that if separate feedlines were employed for each
> direction (supposedly for either the one-end feed or both-end feed), and
> brought back to the shack, they could be combined with a tunable circuit
> to create a steerable rearward null. I believe RCA and others built
> Beverage arrays that utilized this and other types of combining back in
> the early days of the Wave Antenna.
> Garry, NI6T
I've read Misek's book and was intrigued in the null steering
possibilities. Joe, W4TV reminded me of it a little earlier. It might make
an interesting little project when the snow is flying this winter and
stringing wire isn't so attractive.
Ken - K4XL
UR RST IS ... ... ..9 QSB QSB - hw? BK