Modifications to DC508 Frequency Counter

Gary Robert Bosworth

Does anyone have the original application note that describes exactly how to modify a DC508 1GHz Frequency Counter to include Option 1 and Option 7? I believe the modifications are extremely simple. These modifications allow the Frequency Counter to interface directly with the 492/494 spectrum analyzer and its tracking generator.



I have the info for DC502 which can use option-7 and one of our members (Edgar) has been looking at doing PCB for it; not sure what progress he's made though.

Check out the threads for TM503 modifications and DC502.


Nigel G8AYM


If I remember correctly, the DC508 option 7 parts are installed on the same board as the PLL used to multiply up low frequency signals. The service manual should have the schematic for that section. It is not a separate stand alone board as with the DC502.