Thru Hole Digital Dial / Frequency Counter

Through Hole Digital Dial/Frequency Counter


Product Discontinued


The QRPGuys Thru Hole Digital Dial/Frequency Counter is a small five digit led digital dial kit using all thru hole components with optional programmable I.F. frequency offsets. It can also be used as a standalone frequency counter. It is only 2.25”W x 1.50”H x .38″D., Useable range is 100Hz-50MHz. It has a low current usage (~20mA), and a high impedance input. The kit comes with all stainless steel mounting hardware, nylon spacers, and a red Mylar lens for mounting inside your chassis. The circuit used is basically a DL4YHF counter V2 with the extra digit and 2N3904 preamp, packaged to fit neatly within your project case. A Google search will reveal numerous display variants and modifications for experimenters for over a 10 year evolution by Wolf. There have been many diverse mods., prescaler, extra digits, RS232 port communication, etc. by others worldwide around this clever code. Use this as a platform for your experiments, improvements and share with others.

Connections are made to your device via .100” header pins, or use the positions as solder pads. The tools required are a soldering iron with a small tip, rosin core solder, small side cutters, and can be built in an hour. On a difficulty scale of 1 to 5, 5 being the most difficult, this is rated at 2.

Sensitivity measured in (RMS) at 50Ω impedance :

1.00 MHz  – 10mV
5.00 MHz  – 11mV
10.0 MHz  – 18mV
15.0 MHz  – 26mV
20.0 MHz  – 38mV
25.0 MHz  – 50mV
30.0 MHz  – 64mV
40.0 MHz – 100mV
50.0 MHz – 150mV

Limit the input voltage to 2.0V

Digit Resolution:

100Hz-9.999 kHz –
10kHz-99.99 kHz –
100kHz-999.9 kHz – xxx.xx
1MHz-9.99 MHz – x.xxxx
10MHz- 50.00 MHz – (x.xxxx with programming trick) see manual p. 6

Click here for assembly manual

Usage Manual