Hello,
I have searched the archives for this, but I do not see an answer.
My Question:
What is the reason that I show *very weird* SWR curves at VHF/UHF when
feeding through UHF bulkhead connectors that are 8" ( and/or 4") long when
measured into a known 50 Ohm load good through VHF.
My Situation:
My feedlines enter my house/shack through two bulkhead "panels" connected
with 9913 equiv. between. You can see pictures and a "story" at this web
page http://home.comcast.net/~k8bb/ant.htm which explains why I have this
arrangement and how I went about installing it. Through process of
elimination, I have determined that somewhere between the shack panel and
the outside panel there is occurring what I think is some sort of impedance
mismatch that is causing high and very inconsistent SWR at VHF and above.
My Suspicion:
I think that the bulkhead connectors that are feeding through the panels
(probably the 8" ones?) are not a consistent 50 Ohms throughout and are
causing enough of a "bump" in the system impedance to cause bad SWR readings
on 2m and 70cm. The 4" (UG-363/4INCH) and 8" (UG-363/8INCH) bulkheads were
purchased through The RF Connection: http://www.therfc.com/uhf.htm
Maybe Not The Coax?:
The coax that connects them is 9913 equivalent (JSC Wire and Cable Type
#3500) from a local CB shop. It is not exactly Belden or Times, but I have a
lot of experience with coax and connectors and the stuff "looked and felt"
quite good. (In high school, I worked in a local CB/HAM shop and installed
HUNDREDS of PL-259 connectors on countless types of coaxial cable. I
developed a pretty good sense of what good cable and good connectors were
all about. The connectors are all Amphenol with Teflon.)
Eh? Ideas? Suggestions?
Thanks for reading ... Happy New Year
Don Chisholm K8BB
Pontiac, MI
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