--- In FT817@e..., ka4lbd@a... wrote:
concerning postings #6948 and 6957. Several samples of speaker
twinlead have varied from 70 to 80 ohmns. You might refer to
article "Identify that unknown feedline " in July 2000 CQ
For those with an MFJ or other antenna analyzer that can measure
reactive impedance, it is possible to identify feedline Z with a
simple test. First, find a frequency at which an open piece of
feedline looks like an open quarter wave stub; it will read as a
short. Then reduce the frequency to one half of that value. The
capacitive impedance shown will equal the characteristic impedance of
the line. (The input reactance of a 1/8 wave stub is equal in value to
its characteristic impedance.)
My MFJ has a "coax loss" mode, but I have yet to use it. THe ARRL
publications I've seen lamp or speaker cord mentioned in suggest that
it wil have much higher loss than coax.
Cortland
