Logging channel frequency with received messages

[azGreg]

Is it possible to retrieve the channel frequency with each received message? (to command shell output, or other location)
I normally work with C, and am not very familiar with Go for finding where to alter the code.

[bemasher]

The information you're looking for isn't available at runtime because rtlamr doesn't make use of any frequency information for demodulating and decoding messages. Adding that functionality would need a pretty substantial overhaul of how rtlamr works.

The most straight forward option would be to use the -samplefile flag to save unprocessed samples to disk, and determine frequency for each message in a post-processing step.

[azGreg]

Thank you for the timely response, and the tool itself. It is helpful for me.

I see from some of your other replies some code to decode a sample file. However, I am unsure how I would try to infer the frequency. Is the sample file the IQ segment for the duration of the unprocessed full bandwidth sample? Or is it restricted to the channel bandwitdh? I guess I have some digging to do.

Thank you, Greg

[bemasher]

Samples dumped using the -samplefile flag are exactly as they were received from the radio. They are truncated in time to only the blocks where rtlamr correctly decoded a message.

How to determine frequency from these samples is out of scope for this project, you'll need to read up on signal processing to determine the most appropriate method for your purpose.