Hi Lane,
,
> I just picked up an MFJ 259 (not the newer "B" version). Was wondering if
> any of you all have tried it as is, and, with the optional "grid dippper"
> add on.
The 259 is pretty useful.
The grid dip option, however, is an improvement of something that was in
QST or some other magazine.
The idea is poor. Mutual coupling between two inductors is a function of
inductor Q. Since the Q of the untuned inductor used as a coupling coil by
the 259 is very low, especially when compared to the very high Q of an
inductor that part of an oscillator tank circuit, you won't get very good
when coupling to low-Q external circuits.
If the external load is high Q, it will couple much better for a given
spacing and flux density.
MFJ does import a good dip meter that is a off shore clone of the old Heath
Dipper. Since the external coil is part of a tank circuit, it does have
high mutual coupling even to lower Q loads.
73 Tom
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