[R-390] R-390A Design Improvements
Tisha Hayes
tisha.hayes at gmail.com
Tue Feb 22 12:38:30 EST 2011
I don't think any one of us can challenge the collective wisdom of the
entire Collins design team.
There are areas in the receiver where maybe a little bit more attention
could have been paid by some of the individual designers. Some include;
AGC action and the "moment of silence"
Audio response (fine for military standards but maybe a bit poor for some of
us)
Overdoing the entire "cost reduction" scheme
Narrowing down the front end to improve the IP3
If you want to put in a different AGC switch, new capacitor and rewire a bit
you can come up with better AGC action (the way it should have been done).
By changing some caps you can reduce THD (total harmonic distortion) and
restore some frequency response to the audio.
If you want to put a relay and tube at the mysterious blank plate on the
audio deck, make a slight mod to one front panel switch stop you can restore
squelch functionality like the original R-390 had.
If you want to narrow down the IF stagger tuning and maybe add a roofing
filter the radio may work a bit better on closely spaced signals.
We are not talking about major reworks like replacing all of the tubes with
transistors or rewinding coils in the RF stage.
Progress forward may be in little steps, sometimes smaller than what many
may appreciate.
--
Ms. Tisha Hayes/ AA4HA
----------------
"I'll be a diode, cathode, electrode
Overload, generator, oscillator
Make a circuit with me." -- The Polecats
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