Dear Conrad, You can download the manual for the 5328A Frequency counter from http://bama.edebris.com/manuals/hp/ If you look at page 175 (on Adobe Acrobat) you get the circuit and details of the PCB

G0RUZ Conrad wrote: I got one of these PCBs + OCXO recently. It is for an HP counter. Details are in the manual. I have it as a PDF. Iwill dig it out and send it when I get a minute. The counter is th

Talbot Andrew wrote: I am going through the process at the moment trying to do it reasonably on the cheap. I have aquired a Vodafone mobile connect card on Ebay with I hope will do the job. I will att