Is the change the filter bandwith possible?

[Olaf Keller]

Hello all,

sometimes, when I decode telemetry signals from the birds, I want to play the bandwith of the signal.

I know, that i can change the bandwith with the change of the modulation-slider between FM_D , FM, USB and so on. But i think sometimes it would be nice to change the bandwith for e.g to 12 KHz or 14KHz. Is it possible to do that in Skyroof?

Greetings from DH1OK

Olaf

[Alex VE3NEA]

No, there is no adjustable bandwidth. SkyRoof delivers a 48 kHz stream to the external decoding applications, and it is those applications' responsibility to do any required filtering. Besides, SkyRoof now has its own telemetry decoding built in, so the need in external applications is greatly reduced.

[Olaf Keller]

TNX fer the answer Alex 

[Thomas Schuessler]

Alex,

I think what is being asked in relation to filter bandwidth relates more to controlling the audio passband for phone or CW.  Say you have two voice QSOs next to each other.  By trimming the audio bandwidth or ever the rf bandwidth of the signal that is being demodulated, one can improve clarity.  Much like we do to filter out adjacent QRM in a crowded HF band with IF Shift and AF HI/LOW filtering.  All the SDRs and all the other software I have ever used support bandwidth trimming.  HDSDR, SDRUno/Connect, SDRConsole, SDRSharp and on and on all support this function via handles on the active block that is the tuned part of the passband.  So you are saying that Soapy SDR does not allow this type of action.  Bandwidth IS being adjusted by mode, CW, SSB, FM, but it cannot be tweaked? 

I have seen this thread before, but never a real good answer of why it is not desirable or feasible to do so.

Tom, N5HYP

73

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[Alex VE3NEA]

Olaf was asking about the output stream that he is using to decode telemetry. Given the heavy DSP in the telemetry decoders, this is not really necessary. Making the audio filters adjustable would make sense though.

SoapySDR feeds the data from the SDR to SkyRoof, it does not do any filtering.