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Re: [TowerTalk] 4 Sq array Dx or Hi Z

Subject: Re: [TowerTalk] 4 Sq array Dx or Hi Z
From: Roger D Johnson <>
Date: Thu, 06 Sep 2012 20:58:18 -0400
List-post: <">>
If the current preamps are the same as the ones I purchased several years ago,
this is not true. There are jumper blocks that allow one to insert various L 
and C
combinations for various freq ranges but it is not required. I measured my 
on a VNA and found that putting a jumper in the L1MF position (220uH and 1000 
from the input to ground increased the gain across 160m by approx 7 db. It 
caused a
faster rolloff through the BC band and gain above 160m dropped off to normal for 80m.
I found the supplied 108in whips to have inadequate pickup on 160m and made 4
20ft elements out of old beam parts. With the longer elements, I no longer needed the
L1MF jumper in place.

Both the DXE and HiZ 4 square RX arrays use "crossfire phasing" as described by
W8JI on his site. This phasing method allows a unidirectional pattern over a 
frequency range.

I also have the HiZ 8 circle array which IS a single band array. It will receive over a
large frequency range but the pattern is not optimum.

Comparing the two arrays on Top Band was interesting. The 8 circle definitely 
better due to the narrower beamwidth but this is also it's Achilles heel. Signals off the side of the selected azimuth are often not heard unless strong. I usually use the 4 sq for searching for that reason. I have recently put up a 500ft Beverage and it sometimes
hears better. I believe this to be due to it's having a higher angle pattern.

The old idea that you can't have too many antennas on 160m is true!!

73, Roger

On 9/6/2012 7:34 PM, Rick Karlquist wrote:
One thing I am surprised no one has mentioned is that the
DXE preamp requires the user to tune a front end filter to
a particular frequency range.  This makes it into a 1 band
solution.  A receive 4 square might be useful on more than
one band and it is also useful to be able to receive WWV on
2.5 MHz for testing purposes.  Another disadvantage of the
DXE front end filter is that component tolerances will result
in phase differences between units that will degrade the

The Hi Z preamp is truly broadbanded and is checked at the
factory for phase matching.

Rick N6RK


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