[TowerTalk] Single boom solution-

[NPAlex at aol.com]

Subject: [TowerTalk] Single boom solution
To:  towertalk at 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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