Thread: Using Tuner to Determine Line Input Impedance
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Old June 3rd 09, 10:19 PM posted to rec.radio.amateur.antenna
Owen Duffy Owen Duffy is offline
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Default Using Tuner to Determine Line Input Impedance
dykesc wrote in news:22d6efc6-76ca-487a-9fc1-
:

....
I am concerned about an RF field from a local broadcast that may be
causing issues with using the low power MFJ 259B. When I use the auto
tuner I am tuning at 10 watts so plenty to counteract any local rf on
the antenna. I really need to back calculate an impedance from the
inductor, capacitor, and final swr from the auto tuner.

Why didn't you say that the first time?

Tom Rauch (one of the designers of the '259B) posted this info re
interference:

"BC interference causes the bridge in the analyzer to remian (sic)
unbalanced even with very low SWR, so the analyzer will read a fixed
minimum SWR when BC interference. It will read that way on any frequency
from dc to daylight. For example if the unit falls asleep the SWR meter
won't drop to zero. That's an indicator of BC interference or external
voltages being applied to the measurement port."

Owen
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