You have tested over sufficiently long of a time with enough different
signals to tell that it really isn't working haven't you?? I have 4-squares
on 40 and 80 but only 2 phased inv-L's on 160m. fairly frequently on 80m
the conditions are such that there is very little f/b or f/s directivity on
many dx signals, I assume because those nights the arrival angle is so high
that the phasing is way off... think of it this way, as the arrival angle
goes up higher and higher the phase difference between the signals on each
of the verticals decreases so its not the expected difference you cut your
phasing lines for... eventually if the signal were coming from directly
overhead there would be no difference in the 4 verticals so no directivity
at all. Of course for short hops that would be even worse. I wouldn't call
it broke until at least a couple months checking signals over a variety of
fairly long paths with quiet conditions, if its only been up for this summer
I wouldn't make any conclusion yet.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Roger
Parsons via TowerTalk
Sent: Wednesday, October 01, 2014 15:49
To: towertalk@contesting.com
Subject: [TowerTalk] Receive 4-Square
I would appreciate some help with my 160m receive 4-square antenna. It has
horrible directivity which I presume means that I have the phasing or
amplitudes wrong.
The array consists of 4 passive vertical antennas, spaced quarter wave
across the sides, each 25' high and top-loaded. Each has 8 50' ground
radials, is resonant on 1850 kHz and is loaded to 75 Ohms - all exactly as
W8JI. I am confident that this part of the array works properly.
There is a pdf copy of the schematic at:
https://www.dropbox.com/s/2wg3kj9r42woqbi/Vertical%20Array.pdf?dl=0
Ignore the excessively complex control circuitry - that bit also works fine!
I sum the two middle elements with a two way hybrid combiner, and the
middle, front and rear elements with a three way hybrid combiner. These are
commercial units and are claimed to have excellent phase and amplitude
balance. The only real difference (I think) between my circuitry and other
published designs is that the two way combiner allows me to use a single 75
Ohm phasing cable rather than two in parallel.
So what have I done wrong?
73 Roger
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|