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Old April 20th 09, 01:49 PM posted to rec.radio.amateur.antenna
[email protected] jimlux@earthlink.net is offline
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First recorded activity by RadioBanter: Jan 2007
Posts: 61
Default Variable phasing vs 4-square

On Apr 13, 2:18*pm, "Bill Ogden" wrote:
I am trying to understand the practical differences as a receiving antenna
between (1) two "active" verticals with a variable phasing control, and (2)
four "active" verticals with a switch for four different directions. *My
interest is mostly for 80 meters. The physical differences are obvious, of
course. This is mostly in regards to the two different DX Engineering
products.

Is there a significant improvement using the four-square version? *Lower
noise? Lower angles? Tighter "beam"?

Bill
W2WO



A phased array with 4 elements compared to one with 2 elements, can
*potentially* have more gain, and better control of side and
backlobes. It's just because you have more things to adjust to control
the pattern, so you can get "closer" to whatever pattern you want.

A two element array with variable phasing has the nice property that
it's possible to put a "pattern null" on an interfering source (in
fact, you can put N-1 nulls where N is the number of elements), and
for low bands, that can be real useful. Forward gain (on receive)
isn't all that big a deal on low bands because of the usually large
atmospheric noise.

A classic 4 square doesn't have the flexibility of nulling noise,
because it has only 4 (or 8) "beam positions" and you'd have to hope
that one of the patterns produced happens to reduce the interference
you're trying to suppress.

None of the inexpensive simple phased arrays has a very narrow beam
(compared to something like a 3 element Yagi for 20m), so the real
advantage is in having something that can be adjusted at all, compared
to a fixed dipole.