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Technical Topics => Equipment => Topic started by: Sky Waves on December 30, 2018, 1657 UTC

Title: audio recorder
Post by: Sky Waves on December 30, 2018, 1657 UTC

Hi. Great site. I'm not new to radios but only dabbled in SW/pirate listening. How does one monitor, say 6925 mhz for extended periods? I'm thinking some kind of software digital audio recorder or is analog recording equipment preferred? Also how do you manage the time stamp? I can see how that would be easy with a software audio recorder?

Thanks

Title: Re: audio recorder
Post by: ChrisSmolinski on December 30, 2018, 1742 UTC

In my case, I record the entire 6800-7000 kHz 43m band with my SDR, and then go back and look at the recordings with mySdrPlayback: https://www.blackcatsystems.com/software/sdr_iq_recording_playback_program.html

It displays a waterfall for each IQ recording file, so I can quickly spot any transmissions of interest, and demodulate and listen to them. I can go through 12 hours of recordings in 10 minutes, assuming I don't find anything to listen to  ;D

Title: Re: audio recorder
Post by: Sealord on December 30, 2018, 2048 UTC

Audacity (free recording software) works well & if you kick it off at 00:00 utc then it makes it easy to mark the time if there's any overnight activity.

Title: Re: audio recorder
Post by: Josh on December 31, 2018, 2121 UTC

As stated above, recording the iq stream from an sdr tuned to the desired band offers a lot of flexibility for later analysis. That being said, those files can end up being "huge", unlike an 8bit audio stream.

Title: Re: audio recorder
Post by: Sky Waves on January 04, 2019, 1045 UTC

Thanks everyone for the good ideas. So yes, I did find the SDRuno recorder and as mentioned it can gobble up large chunks of disk space. I have Audacity as well and will select whichever one makes sense at the time of the recording.

Thanks

Title: Re: audio recorder
Post by: Josh on January 04, 2019, 2233 UTC

My next sdr pc build will have a fat (as in size, not format) disk dedicated to iq/audio storage. Something that can help people who don't want huge iq/audio files is to have the recording overwrite itself once it gets to such and such size.