[Boatanchors] GPR-90 Vs R-390A

[Nick England]

Slightly off topic - 
Saw a neat old homebrew receiver at the Shelby hamfest. It was "Collins
architecture" and used a homebrew crystal controlled HF osc. for
bandswitching, an ARC-5 receiver as the tuned 1st IF and fixed 2nd IF, and
then a homebrew product detector. Pretty cool we all thought!
cheers,
Nick K4NYW

-----Original Message-----
From: Al Klase

The primary difference is that the Collins receivers, 51J, R-388, 
R-390/390A, have a crystal controlled first oscillator, while the one in 
the GPR-90 is tunable.  This gives the Collins receivers a tremendous 
advantage in frequency accuracy that established a new generation of 
receivers.