Dick, the ohm meter test is d.c. only but it will detect a shorted or open
cable. The loss has to be determined with real r.f.. Starting with say, 100
watts, how much power is present at the end?
Compare that loss with a chart or on line calculator to see how it is
performing.
Since the ohm meter is d.c., the resistance will not change with age. There
are other ways to determine the loss based on vswr with the end of the
cable open or shorted. That subject is covered well in the ARRL handbooks. The
higher the frequency, the higher the loss and lower vswr and easier to
determine loss.
73,
Gerald K5GW
In a message dated 12/10/2009 2:42:55 P.M. Central Standard Time,
RLVZ@aol.com writes:
Hi Guys,
I'm wondering what the typical resistance should measure on a 100' length
of RG-8 coax with one end shorted? I'm measuring 1.5 ohms when shorting
one end of a 240' length of RG-8 ... is that about normal?
Question 2: Measuring in the above manner, should the resistance increase
as the coax gets a few years old?
I'm looking for a simple way of determining the aprx. efficiency of older
RG-8.
73,
Dick- K9OM
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