[Elecraft] (Slightly) OT: MFJ Magnetic Antenna

Stuart Rohre [email protected]
Mon Mar 17 21:13:01 2003


Rolf, do you mean their loop?   It has a small loop coil coupling to the
large loop structure.  The tuning is a variable capacitor driven by a motor
with its leads bypassed for RF.  Check to see if connections to either end
of the loop to variable cap are loose, or if the plates of the variable came
loose and shifted along shaft shorting rotor to stator, although we have not
seen that with one here.  They are easy to open up, and may actually measure
a DC short since it is loop coil coupled to the larger loop.  The resonant
dip is quite sharp, so you may need to tune very slowly, and approach the
best point from both sides to get centered on it.  A field Strength meter is
useful aid in tune up.
73, Stuart K5KVH