[amsat-bb] Re: Antenna Question
wa8sme at comcast.net
Thu May 1 04:45:49 PDT 2014
I doubt that I have greater understanding of antennas than you do, but I'll
give your question a shot. Actually, I have been working on circularly
polarizing the ARROWS with the WRAPS lately, a work still in progress but
almost complete. So I am throwing out the draft information I have been
working on to date.
You can circularly polarize a pair of ARROWs and they actually work well
together from my experience (one of the reasons I suspect is that the feed
system of the individual antennas is very well matched). If you are
mounting the two antennas virtually on the same boom (sticking them right
next to each other) it might get pretty crowded and interactions
complicated. I have mounted two ARROWs separated horizontally about 3 feet
apart with pretty good success. I have done this with stock ARROWs, and
also with one side with the two meter elements, and the other side with the
70 CM elements (had to drill extra holes for the 70 CM mod), both ways
worked about the same. The tricky part is coming up with the right feed
lines (the transformer lines and the phasing line).
I have a first draft of an article I am working on that describes my latest
effort to come up with a polarity switching arrangement for ARROWs with the
WRAPS, it can be downloaded here (if you have download issues, let me know
and I'll try and get it to you another way).
Click here to view Circling the WRAPS
I will be adding to the conclusion of the piece some suggestions on where to
include an external diplexer in the line to handle the single feed line
issue that you mention in your post.
Anyway, I hope this will stimulate some ideas.
Mark Spencer, WA8SME
mspencer at arrl.org
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