hi there -- Your making this all to hard -- if the coax is teflon then it is
most likely .78 or .89 and if it isn't then it is .66. All of the velocity
factors are in the ARRL antenna handbook. All you really need is information
about the material in the coax and it will be easy to do. whether the center
is foam, teflon, or plastic. take the velocity factor for it and built a 2
port harness. put 50 ohm resistors on the ports and measure the input SWR.
If it is low, then measure the power into the harness and measure the power
at one port. It shouldbe ~3db down. then your good to go. If it looks funny
then meaure up and down a Meg and see if it gets any better. Assuming it
does then your harness is long or short for the frequency you want to make
it for. But most of the time you will be will within the necessary length if
you get the correct factor. No matter who made it. GL -- Rick
On Mon, Feb 16, 2009 at 7:27 PM, Ralph Hogan rhog...@comcast.net wrote:
If you have access to an MFJ antenna anal like the 259 series, in the
manual
it shows you how to determine the VF with it given a known length of cable
to test. Don't know how accurate the measurement will be, but should get
you
close.
Ralph W4XE
-Original Message-
From: Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com
[mailto:Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com]
On Behalf Of mike
Sent: Monday, February 16, 2009 8:17 AM
To: Repeater-Builder@yahoogroups.com Repeater-Builder%40yahoogroups.com
Subject: [Repeater-Builder] Cable velocity
I have been searching for the velocity factor for E86650 cable. This
was the stamp on the cable. I think it is simular to RG-59 but want to
make sure. I need to build a phasing harness and wanted to use this
cable and of course the velocity factor is an important in determining
the length.
Thanks for any help
Mike
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