[Milsurplus] ARR-15 Selectivity

[Hue Miller]

I have run hot and cold on the ARR-15 for years.
On one hand it's very good looking, the tuning
resolution is remarkable for a military aircraft
receiver of those years, and the construction
is beautiful. However, it represents the military's
concern with simplifying down of the radio receiver
function to a box with channel and volume knobs. 
And there seems to be no real simple answer to 
the selectivity. This is the same selectivity situation
with the ARC-2. I have thought of building in a 
MOSFET two-terminal oscillator as a Q-mulitiplier
attached to the first IF tuned circuit. With the 
MOSFET and the Franklin (? correct name ? ) 
oscillator circuit you would minimize the upset to
the resonant frequency of the tuned circuit. 
However, I am concerned as to how well the rest
of the IF's would track this tuned circuit. Or how
well this IF with boosted selectivity would "track"
the BFO. You maybe then need an external control
box with 2 pots, one for selectivity and one for 
fine tuning or tracking adjustment. 
I found the internal audio filter just not useful for
anything, no help.  -Hue Miller