[TowerTalk] measuring cable loss with an MFJ 259B

[Pete Smith]

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
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