It's all about the Software

One of SDR Console's many fine attributes is the ability to read files recorded by Jaguar software (for the Perseus) at the 1600kHz sample rate.

Background: Jaguar can record at the Perseus' software's standard 2000kHz rate, but a separate 1600kHz rate was developed specially for Jaguar. Files at the 2000kHz sample rate can be read correctly by a number of different types of SDR software, and by Carrier Sleuth.

However, the 1600kHz rate files can be a bit more of a mystery, sometimes read as having a 125kHz sample rate, if read at all. In fact, if I haul out Console v 1.5 and use "Program Options / IQ data file" and analyze a Jaguar 1600kHz file, the sample rate is returned as 125kHz.

Is the sample rate somewhere else in the Jaguar WAV file header than where the 2000kHz sample rate is recorded? If so, does someone know where it is, or why the sample rate is being misread if it is in the same place? I guess Simon knows, because Console now reads the correct sample rate....

Parsing a WAV file header is not a skill that I have unfortunately, so thanks for any guidance.

Nick

I don't know anything about Jaguar files, but if you don't get any replies from someone who does, put a (ideally small!) sample WAV file somewhere I can fetch it from, and I'll have a look at it.

John

Sorry for the late reply to this. For some reason, your message just showed up a short while ago.

I can provide Jaguar files of about 400MBytes if that isn't too large. Otherwise, I'll have to see if I can record smaller ones.

Thanks.

Nick

That'll be fine... let me know where I can download one from.

jpsa wrote: Tue May 14, 2024 8:15 am That'll be fine... let me know where I can download one from.

http://7dxr.com/4N/2024-04-08%2018%2724 ... G-100m.WAV should get you a sample file.

Apologies again for the late reply....there seems to be a one week delay in displaying the messages here, so hope that is not happening at your end.

I've had a quick look... the fmt chunk says which looks like 1600 kHz, 2 channels, 16 bits per channel per sample (making 4 bytes total per sample), so I don't know why this would be being read as 125 kHz.

There's also an 'rcvr' chunk which I failed to find much information about with a quick Google, except that it's something to do with Perseus!

jpsa wrote: Wed May 22, 2024 9:39 pm I've had a quick look... the fmt chunk says

Code: Select all

ID='fmt ', size=16, formatType=1, channelCount=2, samplePerSec=1600000, bytesPerSec=6400000, bytesPerSample=4, bitsPerSample=16

which looks like 1600 kHz, 2 channels, 16 bits per channel per sample (making 4 bytes total per sample), so I don't know why this would be being read as 125 kHz.

There's also an 'rcvr' chunk which I failed to find much information about with a quick Google, except that it's something to do with Perseus!

Many thanks.

Now to figure out if some software is digging sampling information out of some other chunk. And yes, the software does drive Perseus receivers only.

I appreciate your assistance with this.

Nick