Hello Edgar,
I simulated your EWE antenna using EZENEC4 and saw a cardiod pattern
with an elevated null to the rear. But I don't have much faith in the
results as the ground resistance is unknown. You would probably get a
better simulation of a complete loop even if the bottom wire was close
to the ground. It seems unnecessary to use the telephone wire as a
sort of litz if you have 500+ ohm resistor in series with the loop.
I briefly used one of these terminated loops on 7MHz about 10 years ago
with good results. When directed on the long path to Europe, the rear
null was very helpful in attenuating pesky VK3 stations. It worked well
in my backyard even with the wire draped over shrubbery. When I put it
on my flat metal roof, it was not directional at all. A wire grid
simulation of my roof showed it to be broadly resonant near 7MHz which
probably explains why verticals on that roof were never good on 7MHz.
These terminated loops intrigue me, as they are like a vertical dipole
with the ends bent around and joined together with a poor insulator and
a loop with a resistor in series. With the resistor correctly chosen
they behave just like the active vertical and tuned loop phased together
which I used on LF when listening to the ZLs on 180KHz in 1997.
Phasing the two together was not useful in that case because the null
was to the West where little noise came from at the times I around
sunset when I was listening.
-- 73, Ric VK7RO
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