Frequency Counter

[azepp]

I guess this is a simple question, but maybe not...

How does a frequency counter work when external of the radio?

I saw a PC6 on ebay, and noticed the back had 2 coax connectors and that was it. So how does it determin the frequency the radio is recieving and allowing to pass through? I can understand how it would work on transmit, but not recieve. What am I missing?

Also has anyone build a N3ZI digital dial (freq counter) and will they work external of the radio?

Thanks for y'alls advice

 

[Robb]

If it has an in and out coax connector; then it can only read TX and not RX.
The freq counters that have to be wired into a radio are the ones that show the RX freq...

 

[azepp]

Now that makes sense... Okay and just because I am curious, simply put how does it work when wired internally? I have seen where it is supposed to plug up to a 6 pin connector in the back of the radio, but what are those wires hooked to?

Do you know of any links that show good schematics of frequency counters, that are mde to be wired into the radio?

Thanks