A friend and I have been corresponding about seeming anomalies in results
obtained when attempting to measure cable loss with the MFJ-259B.
With the opposite end of a 50-ohm cable open, the manual says, and I would
expect, a gradually increasing loss as the frequency increases. Instead, what
we both see is variation above and below an increasing average value. With a
100' piece of RG-213, he is seeing swings of as much as .5 dB, which I assume
rules out A/D converter jitter as the cause, so the questions are:
-- what is going on?
-- what value represents the real loss of the cable? Do you need to draw a
loss curve that averages out the variations in order to compare your results
with the cable spec?
73, Pete N4ZR
The World HF Contest Station Database
Full details on 3165 contest stations
at http://www.pvrc.org/WCSD/WCSDsearch.htm
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|