I put my DX Eng 4 sq right at a corner of my lot. A 4' ground rod only
worked ok, but in a pretty wet area most of the year, so I added three
15 foot bare #14 Cu radials for drier times. Two along the 90 deg
baselines as keeping radials away from the feedline to the central
switch seemed a good idea. The third does go onto a neighbor's yard but
both sides are dense forest/wet, and I got permission. The baseline is
the 70' compromise dimension for 160/80. I used 11' high elements - 5/8
& 1/2" Al 6' tube also from DXE. I'm planning to add 6' more of 3/4"
tube. I made my own mounting plates to hold the elements and preamp box
to the ground rod from 3/8 acrylic.
Other than having a noisy cable which I fixed, it has worked very well.
How well depends on the arrival angles but 3+ S units are pretty common
F/B. My baselines are N-S-E-W so mine has the directivity you desire.
Grant KZ1W
On 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.
I am wondering if anyone is willing to give me input on my situation. I
need the best option for narrow beam RX.
There are neighbor houses (noise sources) close to the property line on the
east and west sides, and my house is on the south side, of the proposed
receive antenna area. So I need both good front-to-back and good
front-to-side rejection.
The least visually intrusive antenna system for the front yard would seem to
be something using short verticals or perhaps loops or flags hidden in the
landscape plantings.
Overall front yard dimensions are approx 130’ x 130’. Property line
alignment is N-S. Desired receive directions would be NE-Europe, NW-Asia,
SE-Africa, SW-VK/ZL. ( An aerial view of my QTH is available on Google
Maps, satellite view )
Ground conductivity is poor, so I will need supplemental ground radials if I
go with RX verticals. I cannot run ground radials onto my neighbor’s
properties, so putting the RX verticals right on the property lines, with
only half a ground radial system probably would not work properly.
Recommended distances for a 160m four-square are either 135 feet which is
not do-able here, or 80 feet which is do-able and would allow for 25’ ground
radials around all four RX verticals - but the side rejection looks to be
minimal with an 80 foot array spacing.
The other obvious options to a four square might be a pair of short
verticals or flags or loops using an Antenna Phasing and Noise Canceling box
such as the NCC-1.
Any advice or hearing of your experience with a narrow beam RX system in a
similar situation would be greatly appreciated.
73
Lloyd - N9LB
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