Wide TX BW

[andrew479]

Hi,
is it possible to set TX Bandwidth, both audio and RF to 22kHz? I made a custom filter, but it seems only 4k is coming through.

Thanks,
O.

[Simon G4ELI]

Which radio? I've tested with Pluto and that works OK at 6kHz. There may be other filters restricting the audio to 6kHz.

What will you TX at 22kHz?

[andrew479]

LimeSDR Mini, but it shouldn't make any difference - 22kHz bandwidth should be no sweat, when such SDR is used for DVB-S2, with 7.6MHz BW.

What will you TX at 22kHz?

DRM@20kHz with 1kHz offset. It seems none of TX-able SDR software can handle it with no packet loss. SDRAngel can do up to 250k easily (did some WFM tests), but introduces all sorts of clicking sounds, which cause the stream not to sync properly.

[Simon G4ELI]

I'm sure my modulation code will not handle this sort of bandwidth, it's wasn't really designed for more than 6kHz.

[andrew479]

OK, the limit seems to be set at 6k.
Audio BW is set to 20 - 20000Hz
Using Sync RX while having Wide-U selected at 24kHz
As input I'm using Goldwave's own noise generator, full range for 44.1kHz stream, fed through Hi-Fi Audio Cable

Anything else should be checked?

'hhss' (sorry for the name) uses 20-20000Hz response, using Blackman window:

[Simon G4ELI]

This is just the main filter, there are other filters in the modulation chain (not easy to write) which prevent you generating more than 6kHz using SSB.