Shortening Elad FDM-S2 Files for quicker uploading

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John Faulkner, Skegness
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Shortening Elad FDM-S2 Files for quicker uploading

Post by John Faulkner, Skegness »

Is there a way to reduce the length of an existing SDR file?

I want to upload a file which is one minute long (2.1 GB!)and there is a three second meteor burst on it. Are there any applications (Other than WavChopper, which cannot handle FDM-S2 files.) for extracting the three seconds and deleting the remaining 57 seconds?

Thanks.

Tim Bucknall
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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by Tim Bucknall »

good post
Rx: Burkhardt Reuter RDR54D1, Elad FDM-S2, Airspy HF+ w/ HS Publications 6 Element R3 -R5 Yagi on rooftop rotator V/H polarization options. Pira P275 RDS analyser

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John Faulkner, Skegness
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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by John Faulkner, Skegness »

I will use Monkey's Audio to APE the file in the meantime. ("APE" = ZIP) This halves the size of the file and is a big step up from standard ZIP files which would be larger. But you will need to download this software to un-APE it. https://www.monkeysaudio.com/ It's a simple programme. No pop-ups or spam, etc.

SDR file link to follow.

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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by John Faulkner, Skegness »

File still uploading on my slow ADSL connection. It will be sometime mid-morning when it finishes and I will be in the land of Nod by then. More tomorrow.

Log here: viewtopic.php?f=72&p=25553

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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by John Faulkner, Skegness »

https://mega.nz/#!n2olkaab!g6xTHeqMp-4F ... 1ueori-VN4

The meteor burst occurs at exactly 06:53:12 and lasts for 7 seconds.

bristolpirates
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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by bristolpirates »

Have you tried playing the file back and recording a new file simultaniously at the point where the burst happens? I know this can be done in SDR#, but no idea if it will work in your software.

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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by John Faulkner, Skegness »

That's an interesting idea. I don't know how that would work. I would somehow need to run two x FDM-S2 software. That does not work. Or maybe there is a way?

I just tried SDR Console v2 and this immediately overloaded my last remaining brain cell. So I looked on the internet for SDR# and I cannot find it.

EDIT: I just found a backup of an older version on my hard drive. Unfortunately, it only comes up with AirSpy error messages when I attempt to access settings. I can already feel the tension rising if I have to mess around endlessly to get it to work. I am not good with these things.

bristolpirates
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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by bristolpirates »

If you look for Airspy, SDR# is part of the software package that can be downloaded for free from the download section.

Then, it's as simple as opening your IQ file and making sure it plays back correctly, before setting it going and waiting for the moment when you need to hit record.

I'll d/l your file and give it a go here.

NOTE: The latest version of SDR# will allow you connect to SpyServers too, so you can have a play with some SDRs in other parts of the world (it's a bit clunky at the moment, but I'm sure they'll refine it as time goes on).

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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by bristolpirates »

I forgot to ask, what is the center frequency for this file?

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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by John Faulkner, Skegness »

105.1


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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by John Faulkner, Skegness »

Thanks BP.

Strangely, I cannot play the file. The FDM-S2 says "File not reproducible!". Has this been converted for Airspy users?

bristolpirates
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Re: Shortening Elad FDM-S2 Files for quicker uploading

Post by bristolpirates »

Well, I think this might be a problem with IQ Files not really being standardised.

I can play back your files but I have to adjust the filenames so that they contain the start time and center frequency, because that is how SDR# knows those things.

This indicates that your software might add an additional header with the time, date, and frequency, which SDR# does not.

We can try a couple more files though:

https://mega.nz/#!PA1x1I6C!UFvbZrYB9tdO ... 98VQcYZNco

https://mega.nz/#!zdk3kIwL!UqMVeCuH94J6 ... IoUxlPRn4k

06-00-13_105100kHz - 2019_01_25_06_00_00_FDMSW1_Rec_RF_053_ExpEdit001.wav is an experiment where I've copied a section of your original file to the beginning of my edited file, to see if the header information gets copied across. Try this at a non-critical time as it'll probably crash something, or choose not to try it at all. It played fine in SDR# but that's probably because SDR# doesn't mind these kind of edits too much.

SDRSharp_20190127_102741Z_105100kHz_IQ.wav is re-recorded through # again, but using a different method. We'll see if it preserves the details you need to play it back this way.

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