The PLJ-8LED-H frequency counter module is a very versatile unit that can be picked up on Ebay for around AU$16.00 - AU$20.00.

The module comes ready assembled and calibrated and has a 13.000MHz temperature compensated voltage controlled crystal oscillator (VC-TXCO) which has frequency stability of +/- 2.5ppm. There is also a variable trimmer enabling you to set the counter exactly on frequency if you happen to have a standard hidden away in a cupboard.

Frequency range is 0.1MHz to 1.1GHz. Check out SV1BDS website for his excellent review ; SV1BDS review

Here is a link to a PDF manual which is excellent in content and has been written with input by ZL2PD. ; manual

The module I got (within two weeks of ordering from China) is pretty well spot on using WWV as a standard with a well warmed up TS-590.

I built mine in a copper clad housing made by cutting up double sided blank PCB. I have put two 9Volt batteries in parallel - the counter operates with a supply between 9V - 15V dc.

A tip on cutting this kind of board is to use a stanley knife, or similar, and score both sides at exactly the same length on both sides and just snapping the board, it will start to tear from one end of a cut and give you a nice straight break.

The following photos show the various stages of build and the final unit. The back section of the box is simply held on with double sided tape which will make easy access once the batteries need changing.