Good morning.
Haven't located the original beginning of this thread, but will jump in here!
First, the 100' feedline comment in the our manuals is not a big deal.
Referencing a feedline length was noted many years ago in some commercial specs
and it seemed like a good addition. This length was selected as a typical
installation length, so that a customer would have an idea of what to expect.
As
most people know, coax has a small amount of loss (some more than others), so
the VSWR curves will be slightly broader than if measured directly at the
feedpoint. For our testing, we use 100' of new RG-213; however, always desiring
to be conservative in specifications, the VSWR data is done using a 50' section
of line.
Regarding the C-31XR and 15 mtrs, there is a paragraph that was added to the
manual in perhaps mid-late August. It relates to the positioning of the
parallel
feedlines between the 10 mtr and 20 mtr drivers. (The 15 mtr driver is open
sleeve coupled to the 20.) The manual and accompanying photos and drawings
apparently did not convey the instruction to not spread them apart. If they are
spread apart in this manner, the 15 mtr VSWR curve will be low in frequency and
also high in value. They need to be either parallel, or a pulled close together
(bowed inward).
Had an installer call me on Friday from atop a tower with this exact condition.
He "squeezed" them back together (they were pulled apart as far as they would
go) while we were talking and 15 came right in. He then tweeked the 20 mtr a
little and came down. This was the second C-31XR he has installed and had done
the first one "right." He vowed to read the manual when he puts his own up in
the next week or two!
Have a great day & 73,
Tom Schiller, N6BT
President, Force 12, Inc.
Amateur Antennas, Commercial Towers & Antennas
P.O. Box 1349 Paso Robles, CA 93447
Phone: 805.227.1680 FAX 805.227.1684
Web Site: http://www.QTH.com/force12
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