The FC-30 is a universal frequency counter which indicates the frequency of the selected channel. It is designed for use in CB and Amateur radios. All connectors, wiring, hardware and instructions are included.
Like other frequency counters (FC-390/FC-347), this one has the connector to plug into the back of many popular radios. It ALSO has an RCA jack to directly read frequency via a probe, sensor or antenna input. That’s what truly sets this one aside from the rest. Take note that it is considerably larger than the FC-290/FC-347 (about 80% larger).

WORKS TWO WAYS, EXTERNAL OR INTERNAL.

1) From rear port sense radio TX energy to display direct frequency (AM only) or

2) From data port read radios oscillator frequency and displays all the time, RX and TX and both AM and SSB. (many radios have this port already or you are supplied internal wire harness to install)