Regarding Observation 139590 …
So I just got everything connected last night. Still want to clean up a few things. ( The jumper from the bias tee to the airspy etc. ) Is my RF gain to high? if so what are acceptable vaules for the airspy? currently when I click on SATNOGS_RF_GAIN is blank. Goal is to be added to the esteemed list of GS that are decoding data. and the even shorter list of those using an omni.
MY setup is a custom parasitic Lindenblad measured VSWR at 436MHz 1.5 (It goes practically to 1:1 at 20MHz down from 436 but I didn’t dare tune it any further for the fear of screwing it up.) less then a meter down the cable I have a Mini-70 amp then about 15m cable run to the airspy and PI 3 B+.
Also when shall I declare myself operational?
For the Airspy, the RF gain will be mapped to Airspy linearity gain with range 0…21. I usually use around 15-18 without LNA. With LNA you probably want to use less. The easiest way is to try in real time with an SDR application and adjust gain for best SNR. Once you have a good gain setting, you can adjust the waterfall levels for best visual appearance.
thanks. I’ll guess I’ll take the Pi out of the circuit for awhile and plug in my laptop. I looked at a few of your observations your noise floor seems quiet low. Do you just live somewhere that is RF quiet or is it more due low gain before your airspy?
second question to decode do I need to just improve my SNR or are there any configuration settings I need to do on the SATNOGs client? Or just forget about being able to decode until I’ve built a rotor. which won’t happen any time soon.
OZ9AEC-VHF1 is in a quiet area. Airspy One is connected to antenna without LNA and here the gain is 76% so it would be 16.
OZ7SAT also uses Airspy One but is in Copenhagen with lots of noise. Here we have filters and LNA in front of the Airspy and the gain is set to 58% which would be 12 for the Airspy linearity gain.
Decoding will happen automatically for the supported modes and satellites. Not all sats are decoded yet.
Thanks for your help. I reduced my gain. seems more appealing now. next I have to find the source of some prominent interference that is always at 437.455. I think its internal to the Airspy. put ferrite cores around all power and data cables did nothing.