[Elecraft] Coax Test Question

Tue Jun 10 18:44:00 2003

Want you want to do is put the dummy load at the end of the coax. Place a
wattmeter between the rig and coax to be measured. Use the highest frequency
you will be using. I typically use 10m. Once you measure the power there,
move the wattmeter to the end of the coax between the dummy load and the
coax. Measure the power without touching the power output of the rig form
the last measurement. The difference in power measured is your loss.
You can compare the loss per 100', as an example, to what the coax loss
charts say the coax should be.

Whenever I install coax, I measure the total loss in it at 10m. and keep a
log on it. Then if I suspect a problem I can measure and check against the
log to see if it deteriorated.
Tony
N2TK

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Francis Belliveau
Sent: Tuesday, June 10, 2003 18:27
To: [email protected]
Subject: [Elecraft] Coax Test Question

With the question about RG58 I thought up a testing idea to help determine
the quality of cox (or loss).

Keep in mind the intent is to get a relative idea, not to measure actual
losses.

Would it make sense to place a dummy load at the back of the rig and measure
say the ac voltage or possibly power being delivered at the load, then place
the same load at the end of a piece of coax and make the same measurement?

Even though the measurement method might be suspect, the measurement
difference should be a reasonable indicator of signal loss.  Is there any
value in this type of measurement?

I was thinking that it would be a good way to judge the usefulness of used
coax donated to the club or pulled from the club's locker for field day use
every year.  We always test to make sure a signal gets through but don't run
any kind of loss test.

Fran

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