[Motorola] Permakay Split Channel Conversion

[Geoff Fors]

Regarding Paul's (W0RW) question about the narrow band filter conversion of
his "antique" VHF high band Sensicon A receiver, I located the data.

The conversion summary is on Page 55 of the red version of Motorola
Schematic Digest.  That was easier than spending all night in the catacombs
looking for the original conversion sheets...

The narrow filter is a TU406 and it's necessary to make 15 changes to the
wiring, mostly changing resistor and cap values, grounding the AGC line and
moving one IF coil tap.

Other than the problem that it's physically too small, I wonder if the
common TU540S narrow filter from a G-strip receiver would work.  Motorola
didn't publish the insertion loss or in/out impedance specs for the filters
so this would have to be an experiment.  Funny thing, I never ran across a
defective full sized Permakay but many of all the other types.

It was a toss-up between which filters failed more often - - the ones in the
HT-200's or the ones in the "E" series high band Motrac receivers
(TFN6017CS -- I still have the # memorized.)

Geoff
WB6NVH