From: i4jmy@n8it.#nwmi.mi.usa.noam
To: cq-contest@contesting.com
Hi guys,
in order to be competitive in the coming WWDX SSB, I'm preparing the
RX antennas, beverages, to enter in an 80m single op.
It is difficult for me to place all the wires radially so i'm thinking
to use a set of two wires (bidirectional) 2 wavelength beverage antennas.
I never used it before, but it has definitely to work.
A computer model I made works infact nicely, but what's makes me doubtful
it's how to realize practically the antenna.
Among the examples I found on the classic literature, the simplest of the
configurations appears that in which one of the wires is left floating, at
the end, while the other wire it's directly grounded (at the same edge).
The feed I found on (Low band Dxing) uses 1:9 a balun trasformer to feed
out of phase, and a second 1:9 transformer (not necessarily a balun) to
feed in phase.
However, my doubt its the following:
the two wire beverage I think to use is then composed by two parallel wires
feed in phase to have one direction, feed with opposite phase for the
reversal beaming.
Altough at the ends one of the wires is grounded, and the other one is
left floating, at the generator (receiver) end both wires should be
terminated on the proper (300-500 ohm) impedance/load.
I "see" on the schematics the impedance match and the phase shifts, but I
don't see any of the "absorbing" resistor.
The only explaination could be that:
or the unused output (2 are present) it's closed on a (proper) load,
or it must be always connected to a second receiver (used as a load).
But I didn't find warnings about this fact.........
Is there someone who already tried (practicaly experienced) with a two
wire beverage ?
How dit it come out ?
Thanks in advance for the replies.
73
Mauri, I4JMY (one of IR4T)
E-mail i4jmy@uugate.aim.utah.edu or i4jmy@migate.ampr.org
/ex
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