Topband: Looking for 160m narrow beam RX advice
jim at audiosystemsgroup.com
Tue Jan 6 12:39:54 EST 2015
On Sun,1/4/2015 10:03 AM, Lloyd Berg - N9LB wrote:
> I have read and re-read the recently posted 160m RX antenna information
> presented on the Top Band Reflector and am sold on building a separate low
> band receive antenna system in my front yard that is away from my TX towers
> in the back yard.
One caution, Lloyd. Do the arithmetic to find the distance between your
front yard and TX antenna as a fraction of a wavelength. When you do,
you'll find that it's not very far away from it. :) An RX antenna may
work there, but don't be surprised if there's interaction.
The tower holding up my SteppIR is about 200 ft from my 160M Tee
vertical. NI6T and N6BV both suggested that I look for interaction.
Carefully measuring distances and azimuths, I found that the tower acted
as a reflector for the Tee, giving me a couple of dB to VK/ZL. I rigged
two wires sloping off the tower and loaded them (one at a time) from the
base against elevated radials. One wire to the east, one to the west.
Modeling showed me that if I shorted the Tee Vertical, it acted as a
reflector to shift the patterns of those sloping verticals 30-40 degrees
to the north.
73, Jim K9YC
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