Recorder Audio Files

[Paul]

My thanks to Support, who as usual came through in a very short time "with the goods," which I reproduce here and hope that it will be found helpful and I hasten to admit that I had no idea hw an IQ recording works (in short - a fantastic facility):
Hello Paul,
We may be misunderstanding what you are saying here, but the recording performed in SDRuno is of the full sampled RF spectrum and not just the individual channel that you are monitoring with your VFO. So for example, if you have an 8 MHz sample rate and have the LO set to 94 MHz, all signals between 90 and 98 MHz will be recorded. If your signal of interest is at 91 MHz, then your VFO must be set to 91 MHz to hear that signal on the recording. If you have a different signal at 93 MHz on your recording, if you change the VFO, to 93 MHz, you will hear the signal that was at 93 MHz. In other words, you record everything that is shown on the main SP1 display. That's just how full bandwidth I/Q recording works.
In the future, we plan to add an option just to record the single channel that is being monitored by the VFO at the time of the recording, so in that case, you will have the option just to record what is shown on the auxiliary SP2 display. This will reduce the size of recorded files considerably and will be of benefit to people who are only interested in a single channel. I/Q recording is definitely important to some people as it gives them the opportunity to record one or more complete bands at the same time as opposed to just a single signal.

[Tech_Support]

Hello Paul,
Many thanks for this. The I/Q recording feature currently available in SDRuno, essentially records the signal that is provided to SDRuno via the USB interface from the tuner/ADC. This represents the total RF spectrum that is viewable within the SP1 window along with all of the modulated signals contained within that bandwidth and puts it in a WAV file container.
When receiving signals normally, you select a particular signal with a VFO and that signal is filtered (channel selected) and demodulated by the software.
Exactly the same process is followed when you replay the recorded I/Q file in that you replay the entire section of recorded spectrum and using the VFO, you can select an individual modulated signal that may be present for filtering and demodulation.
If you move the VFO, then you change the signal that is being selected and if there is no signal present, you will just get noise. That is the nature of I/Q recording.

The signals present in the I/Q spectrum are not audio as such, because they are modulated. They will not be playable in other audio players such as Windows Media Player or Windows Media Center.

We do plan to add audio recording in the future and in this case, only the audio signal after demodulation and in this case, these signals would be playable in other media players such as Windows Media Player or Windows Media Center.

I hope this helps clarify matters.

Sincerely

SDRplay Tech_Support