KA9Q and Airspy Mini

[Ruben Navarro Huedo (EA5BZ)]

Hello my friends:

Installation with KA9Q was 100x100 fine but i doesn't heard anything.

Only listening if Sonde is very very near of antenna (4 o 5 meters).

All is fine with RTL-SDR but KA9Q + Airspy MIni is really deaf :-(

Airspy Mini is running fine with other software

What do you think?

Thank's

[Mark Jessop]

By default ka9q-radio will be using a software AGC to set the gain.

If you have strong local signals, then it may wind back the gain to avoid receiver overload, which could cause it to be less sensitive to far away sondes. 

The gain can be set manually in the radiod config file (the gainstep setting), but if your receiver still overloads, that's going to cause all sorts of other issues (which I would have expected to affect a RTLSDR just as badly).

73

Mark

--
You received this message because you are subscribed to the Google Groups "radiosonde_auto_rx" group.
To unsubscribe from this group and stop receiving emails from it, send an email to radiosonde_auto...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/radiosonde_auto_rx/e4a9a290-1f51-474b-b11a-b66fdf6e8de5n%40googlegroups.com.

[Ruben Navarro Huedo (EA5BZ)]

Tnx for your answer.

I tried setting manually gain with same result

Also i tried listening sonde with SDR# and Airspy Mini and all is fine.

I really don't understand what is happening.

[Mark Jessop]

Does your setup use a preamp and require bias power?

Otherwise, if you've set the gainstep to the same as when testing elsewhere (note that gainstep uses the 'linearity' gain scale), I'm not sure what else could be going on here... We've got many stations running Airspy units without issues.

73

Mark VK5QI

To view this discussion visit https://groups.google.com/d/msgid/radiosonde_auto_rx/698137a4-67d6-40ce-884c-56f5e919bfa1n%40googlegroups.com.

[Ruben Navarro Huedo (EA5BZ)]

No..i am not using a preamp.

I will continue doing some tests.

What rasp are you using?

[Mark Jessop]

We only support ka9q-radio setups on either a Pi 4 or newer. All of my setups are running on RPi 4s.

Anything older than this will likely not have enough CPU to run everything, resulting in many sample drops.

73

Mark VK5QI

To view this discussion visit https://groups.google.com/d/msgid/radiosonde_auto_rx/edbe09ef-80e6-41c1-b060-a419b131495dn%40googlegroups.com.