Subject: [TowerTalk] Single boom solution
To: towertalk@contesting.com
There are two use cases:
1) use case #1: 3 el SteppIR, plus 2 el CC 40 above it.
steppir @ 60, 40 @ 70. Have a 2el 30 design to slide
into the 40m boom.
2) use case #2: 3 el SteppIR with 30/40 DE. This would be
at 70' Doesn't excite me. Would like 2 el on both 30/40.
So...the question is, what might be a reasonable single boom
scenario around the steppIR? Convince the Mertel's to make a
2 el 30/40 using their folded DE? This idea would have TWO DE's,
one for 30/40, the other for 20-6. One could retract the unused
antenna, to avoid interaction. Admittedly, bandswitching in that
scenario would be slow.
So...what would your approach be?
N2EA
==============================================
Jim,
Hopefully in the next few weeks my 4 element SteppIR will arrive and I will
begin the implementation of an array similar to your case #1. The variation
is instead of a CC 40m beam, I will be creating a two element SteppIR 30/40m
beam using two of the 30/40m folded elements. The boom length will be 18
feet, and stacked about 8 ft above the 4 element yagi. Interaction is not
expected to be an issue as one or the other antenna can be "retracted" to
eliminate that issue (allows for relatively close stacking separation). This
design
was inspired by the work of Clay W7CE (check out his website).
This approach requires two controllers and separate coax feed lines, or a
remote antenna switch which is the solution I will use. I am giving up on the
180 deg reverse feature on the 40m array to eliminate the need of switching
the coax from one element to the other. However that could be easily done
with a third position on the remote antenna switch. However the effect of the
unused 40m coax feed would have to be evaluated and taken into consideration.
This could be very complicated solution when considering this arrangement
will also be used as a 2 el 30m beam. So my choice to give up the 180 deg
flip.
Still modeling this approach and at the moment do not have any issues that
appear insurmountable.
Regards,
Norm W4QN
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