BOBTAIL CURTAIN
I have a 40M bobtail up and would like to get some FB(and gain!) to get away
from EU broadcast.I am feeding the bobtail in the usual way, parallel ckt at
the base of the center element against a small counterpoise and gnd rod.
Questions?
1) If I put up an identical parasitic spaced say, 0.125 lambda; can it be tuned
from a reflector to a director by simply changing the resonant freq of the
parallel tuned ckt attached to the center radiator of the parasitic element?
2) Can two identical elements spaced 1/4 lambda be fed at 90 deg and switched
to change direction? I suspect a problem with the tuned ckt feed at the bottom
of the center radiator of each of the two elements, though it seems that a
match could be easily obtained, could the phase be preserved if both parallel
tuned ckts were identical and tuned to try to keep the phase
unchanged?(resonance?)
I have EZNEC-4, but only recently obtained it and I am at the very bottom of
the learning curve and time is running out before heat and hmidity here!
I also have an HP vector voltmeter, dual chan osc, and MFJ 259B, sig gen, etc,
all of which I do know how to use. Top feed at low impedence is mechanically
out of the question here. I have read about phased bobtail curtains on the
internet, but no one seems to describe how.
Any help from a knowlegable person would be GREATLY appreciated.
Thanks,
Sam, W5LU
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