[R-390] Digital readout

[Flowertime01 at wmconnect.com]

Cecil,

There was a series of modules that plugged in.

Some went between the RF deck connector to get B+ and 6.3 AC made to DC with 
a bridge rectifier.

Then there were little BNC tees. These got you the signal from the crystals 
and PTO. The logic gate just count this that these tham and those. Then it just 
counted one of them again but for a short time to fake an additional 455.

Other little modules were high impedance off the little BNC's and used some 
B+ to get the signal up to TTL level.  There was a 6 digit display to get you 
to a 100 hertz.

About 1973 there was a push on to get frequency counters that would count to 
50 Megahertz and cost under a $100.00. 

You could build one of your own these days and use what ever display you 
wanted behind one of the spook flip up covers. Most of it could lay on the crystal 
osc deck.

Roger AI4NI