In a message dated 3/15/02 1:38:46 PM Eastern Standard Time, k9nr@juno.com
writes:
> I had a problem matching my 160 tower due to mutual coupling to a second
> tower only 36 ft. away. My MFJ analyzer said everything was fine, as
> would a GR Bridge. The Delta OIB gave very different measurements.
> After I detuned the second tower, the MFJ and the OIB agreed.
> Since many hams use more than one tower, they may encounter similiar
> problems.
>
One problem that I have noticed using the OIB's in the field is that they
tend to "pull" a bit when you have high reactance values. A GR, as far as I
have seen, does not seem to exhibit this problem. For anyone using a GR
bridge, however, be sure to use not more than about 1 watt from you signal
source on the generator input. Use of higher power will destroy the small
resistor that is at the inpurt of the bridge ( I have done it). I simply use
my MFJ-259 as a signal source and either a Potomac FIM-41 field meter or an
HF rig as the detector.
73................de Goose, W8AV
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