BATC Forum

Hi all,

Trying the Langstone for a few days now and it all works however the audio is very poor quality, gargling and distorted.
Also, when sending CW ID it is unclear, distorted and the tone is not smooth.

Setup:
RPI4 4GB
Pluto SDR Rev.B
Creative SoundBlaster X USB soundcard
Pluto is connected over USB, tried also over ETH, same result, scoring with Pluto_test comes up 1980 so very good.

When trying to run Lang_TX.py on it's own it comes up with an error message something like that sound card is not supporting 48000 sampling rate, switch to 44100 instead. Interestingly, runing the ./run makes it work.
Receive is spotless.

Colin, would you please update also the GRC files on github, they appear to be few versions behind.

Many thanks,

73, Las
M0BOY

Is the "Creative SoundBlaster X USB soundcard" the correct standard soundcard? No it is not.

Non standard set ups are unlikely to work as expected. I would suggest using the recommended parts and see if that fixes it. You must use a 48kHz sample rate.

https://wiki.microwavers.org.uk/Langsto ... ired_Items

Mike

I have to agree with Mike’s comments. The sound card choice is very important. It must support 48KHz sampling. Incorrect sample rate will cause the problems you are hearing.

As far as I am aware the GRC files are up to date but I will check.

Colin.

Thanks gents for confirmation.
It was the only sound card I had around to be honest and I was too excited to get it up and running. A cheap amazon usb one arrives today. Hopefully with compatible chipset.
Regarding the GRC’s, Colin the reason I think they are behind is they don’t contain the “actions” at the end of the py scripts.

The py scripts used by Langstone have to be created manually.

If you want to build them yourself you need to do the following....

Use GNU radio companion with the GRC files to create the initial .py files. (This can be done on a Windows PC, the resulting .py file is the same wherever it is created)
Then manually edit those .py files, incorporating the changes defined in the controlRX.py or controlTx.py files.

Doing it this way allows GNU radio companion to be used to graphically design the main SDR code who I find much easier than trying to do it directly in python.

Colin.

Thanks Colin, much appreciated! Makes sense now, I am running gnu radio on the pi itself with ssh -X, works a treat

In the meantime the new soundcard arrived, works a treat. No more gargling sound, interesting how a posh creative is not good for this purpose .

Again, many thanks and for sure I'll be back with questions and suggestions.

Las