Frequency measurement: I managed to run it only if the input signal is between 4.7 and 5 volts (not to be exceeded). The signal goes directly to pin 3 of the PIC (5V max). An incoming signal amplification circuit must be provided. Quartz measurements: Very poor circuit. It depends a lot on the supply voltage, the temperature and the quartz frequency. Limited use. Measurement examples: (3,2748 MHz -> 0) (4,9152 MHz -> 4,9166) (16 MHz -> 16,001 16,006) (20 MHz -> 20,007) (22 MHz -> 22,007). Strange situation: if the power is about 9 volts, the 4.9152 MHz quartz give these results: -> 14,667 14,669 14,672 14,681 Third harmonica?) Under investigation.

Frequency measurement: I managed to run it only if the input signal is between 4.7 and 5 volts (not to be exceeded). The signal goes directly to pin 3 of the PIC (5V max). An incoming signal amplification circuit must be provided. Quartz measurements: Very poor circuit. It depends a lot on the supply voltage, the temperature and the quartz frequency. Limited use. Measurement examples: (3,2748 MHz -> 0) (4,9152 MHz -> 4,9166) (16 MHz -> 16,001 16,006) (20 MHz -> 20,007) (22 MHz -> 22,007). Strange situation: if the power is about 9 volts, the 4.9152 MHz quartz give these results: -> 14,667 14,669 14,672 14,681 Third harmonica?) Under investigation.

Frequency measurement: I managed to run it only if the input signal is between 4.7 and 5 volts (not to be exceeded). The signal goes directly to pin 3 of the PIC (5V max). An incoming signal amplification circuit must be provided. Quartz measurements: Very poor circuit. It depends a lot on the supply voltage, the temperature and the quartz frequency. Limited use. Measurement examples: (3,2748 MHz -> 0) (4,9152 MHz -> 4,9166) (16 MHz -> 16,001 16,006) (20 MHz -> 20,007) (22 MHz -> 22,007). Strange situation: if the power is about 9 volts, the 4.9152 MHz quartz give these results: -> 14,667 14,669 14,672 14,681 Third harmonica?) Under investigation.

This came with no instructions, but the PCB is labelled with component values so I found it very easy to assemble. A description of how to use the add/subtract functions can be found at http://www.qsl.net/dl4yhf/freq_counter/freq_counter.html (as mentioned by tom_pin in the product discussion). The display is much easier to read if you add a red filter. If I had the chance to make 1 change, I'd provide space on the PCB for 4mm sockets for ground and frequency signal in; then it would be easy to connect different sorts of test lead (e.g. pointy or spring hook).

This came with no instructions, but the PCB is labelled with component values so I found it very easy to assemble. A description of how to use the add/subtract functions can be found at http://www.qsl.net/dl4yhf/freq_counter/freq_counter.html (as mentioned by tom_pin in the product discussion). The display is much easier to read if you add a red filter. If I had the chance to make 1 change, I'd provide space on the PCB for 4mm sockets for ground and frequency signal in; then it would be easy to connect different sorts of test lead (e.g. pointy or spring hook).

This came with no instructions, but the PCB is labelled with component values so I found it very easy to assemble. A description of how to use the add/subtract functions can be found at http://www.qsl.net/dl4yhf/freq_counter/freq_counter.html (as mentioned by tom_pin in the product discussion). The display is much easier to read if you add a red filter. If I had the chance to make 1 change, I'd provide space on the PCB for 4mm sockets for ground and frequency signal in; then it would be easy to connect different sorts of test lead (e.g. pointy or spring hook).