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Possible to to go past 48k bandwidth in WFM

Posted: Wed Nov 18, 2020 7:46 pm
by w2rtv
Hello Simon,
is it possible you could bring the bandwidth of 48k in WFM mode up to 75 or 100k ? there is a new satellite up, Bobcat-1 and is
transmitting 57k6 data. 48k is not wide enough. BFM mode will not work.

73,
Rocky
W2RTV

Re: Possible to to go past 48k bandwidth in WFM

Posted: Wed Nov 18, 2020 7:48 pm
by Simon G4ELI
Rocky,

Yes - but first please send me a good screenshot or better still an IQ (Data) recording, this will help a lot.

Re: Possible to to go past 48k bandwidth in WFM

Posted: Wed Nov 18, 2020 11:38 pm
by w2rtv
ok Simon ,i will get an I/Q recording and a screenshot to you when it goes back to 57k6.
thanks,
Rocky

Re: Possible to to go past 48k bandwidth in WFM

Posted: Thu Nov 19, 2020 12:50 am
by PD3LK
In the past it was possible to add higher bandwiths, they still work fine here: 50/80/100/120/150 Khz but i can't copy/edit them anymore.
Rockey do you know if the D/L freq is 436.600 MHz?

Re: Possible to to go past 48k bandwidth in WFM

Posted: Thu Nov 19, 2020 7:02 am
by Simon G4ELI
w2rtv wrote: Wed Nov 18, 2020 11:38 pm ok Simon ,i will get an I/Q recording and a screenshot to you when it goes back to 57k6.
thanks,
Rocky
What I'll do is run at 48k if the filter is 48k or less, 96k if 96k or less or 128k if > 96k.

Should be easy, I'll just wait for the screenshot / IQ so I know what I'm dealing with.

Re: Possible to to go past 48k bandwidth in WFM

Posted: Thu Nov 19, 2020 8:06 am
by Simon G4ELI
Simon G4ELI wrote: Thu Nov 19, 2020 7:02 am
w2rtv wrote: Wed Nov 18, 2020 11:38 pm ok Simon ,i will get an I/Q recording and a screenshot to you when it goes back to 57k6.
thanks,
Rocky
What I'll do is run at 48k if the filter is 48k or less, 96k if 96k or less or 128k if > 96k.

Should be easy, I'll just wait for the screenshot / IQ so I know what I'm dealing with.
I've just tried this logic with BFM - works well with three different sample rates. I'll add to WFM and post a kit today.

Re: Possible to to go past 48k bandwidth in WFM

Posted: Thu Nov 19, 2020 8:21 am
by Simon G4ELI
Simon G4ELI wrote: Thu Nov 19, 2020 8:06 am
I've just tried this logic with BFM - works well with three different sample rates. I'll add to WFM and post a kit today.
Ah - isn't going to work. The audio output is always resampled to a constant 48kHz in my demodulation engine.

Re: Possible to to go past 48k bandwidth in WFM

Posted: Thu Nov 19, 2020 1:58 pm
by Simon G4ELI
So, the only solution is to add an optional extra for FM demodulation > 48kHz. Let me see the screenshot and IQ data please.

Re: Possible to to go past 48k bandwidth in WFM

Posted: Thu Nov 19, 2020 7:04 pm
by w2rtv
here is my dropbox link to I/Q /wav recording at 57k6
https://www.dropbox.com/s/yvfuwmy6bdj73 ... v.wav?dl=0

Re: Possible to to go past 48k bandwidth in WFM

Posted: Thu Nov 19, 2020 7:08 pm
by w2rtv
ok i am trying to post my dropbox link to recording. i hope it came through.
Rocky