[R-390] frequency counter connection point

[djed1 at aol.com]

It's true that you need to measure all the oscillators to get the actual  
frequency the radio is tuned to.  You could just measure the PTO, which  
would give you the kilocycle reading, but even there it's complicated.  The  PTO 
tunes "backward",  so you would have to have the counter count  backward.  
Then you would have to have some means of correcting for the  inaccuracy of 
the other crystal oscillators.  Too much trouble.
I long ago decided that if I need frequency accuracy better than 300 Hz  
I'll just fire up a ricebox.  The R-390 was a marvel for it's time, and for  
most listening purposes it's still good enough.
Ed