Prescaler front-end to extend the maximum frequency range on a frequency counter.

This will take a 0.1 - 3.5 GHz signal and divide it down 1000 times so you can measure microwave frequencies outside the normal range of your low cost frequency counter.  Example, a 2450 MHz RF input signal will read 2.450 MHz on your counter.  This is from the July 20, 2000 issue of EDN magazine with a few minor modifications.

The NEC UPB1507GV prescaler IC is available from Mouser Electronics.  A Fijitsu MB506 is substituted in the pictures.

Keep the prescaler's RF input low, around 0 dBm (1 mW).  The absolute maximum is around +5 dBm (3.2 mW).

Schematic

• GBPPR Divide-by-1000 3.5 GHz Prescaler  (66k PNG)

Pictures

Select a picture for larger image.

Overview.  RF input is via the top N connector and directly into the a MB506 (divide-by-128) prescaler.  The divide-by-1000 output is via the bottom BNC connector.

Alternate view.

Outside case overview showing the RF connectors, the power LED and switch.  It's built into an old California Amplifier MMDS downconvter case and is powered by an internal 9 volt battery.