@ All My apologies for the poorly asked question and much appreciation for helping me clarify.
@ geckoVN
Thanks for input. I am going to remove the LNA and see if that is the issue. I doubt I ever needed it but as noted in my question, it worked before.
@ fox hunter
The question: * Raspberry – As noted in my question, pi 4, running Bullseye
The question: * Airspy – As noted in my question, bought in 2018 or 2019. I forgot to mention that is the Mini version
The question: * filtered LNA – Don’t know. But if you read my original question you would see that is the same unit that I had working in the past. Maybe it is broken. Not likely. I’ll take it out of the equation.
The question: * Antenna – As noted in my question, Standard Issue Flight Aware.
The question: *Cabling – As noted in my question, Six foot, premium, professionally made, worked in my original setup. Spent 50 bucks on it. The cable is not the problem
The question: *Bias-t – As noted in my question, enabled. Yes the LNA requires it. And as mentioned, it worked before.
@wiedehopf.
Your observation: There is not enough info about the setup – Set up is summarized at the end of my original question. Pi 4 / Bullseye / post 2017 Airspy / LNA / bias t enabled / FA antenna / Six foot, premium cable between antenna and Airspy / Pi powered by POE.
I am unsure of the model of the LNA, I enclosed it in some pvc for weather hardening purposes. I’ll get it out, get model, then remove from the setup so as to reduce complexity. The Airspy I am using is the mini version and was purchased in 2018 or 2019. I am using the default config file with only two changes. Added -b to the parameters and played with the gain setting. Nothing else.
Your wrote: – You could just as well ask how the decoder knows what ADS-B messages are
I could ask that but that but that would be a dumb question. I get how Dump1090 works. My question, poorly asked, was:
“The only clue I have is that the Airpsy I was using for receiving ADS-B can’t be found. So I am using one that I was using for decoding a Russian Weather satellite feed. I have a memory of accessing the Airspy directly and adjusting the frequency it listened too.”
Now maybe my recollection is wrong. Not hard to believe. But what I was asking was if I needed to change anything about the Airspy itself, so as to make it work with Dump1090. I bought three of them, from you I think, at the same time. One was used for Air Traffic Chatter, One for the Russian weather satellite. The third was for ADS-B. I had all three setups working in the past. I lost the Airspy Mini that was part of the ADS-B setup. So, I repurposed one of the other two.
A better way to have asked would have been:
How does the Airspy Mini device know which Frequency it is supposed to listen too? Does Piaware control the setting of the Airspy? Are there any settings? If it was the standard RTL dongle you guys sell, I know it would be configured for 1090MHz. But the Airspy Mini, per my understanding, is a far more flexible device. I am not on expert on RF tech. Don’t want to be. But my intuition tells me that something needs to inform the Airspy as to which frequency it should tune in to. Unfortunately, my intuition and a quarter will only get me a gumball.
Finally, let me stress, all of the equipment I am using, I successfully used before. Other than mounting the antenna in higher location, it is only three feet away from where I had it working before. I could send graphs and config files but I don’t get how that will help in the context of my question.
Thanks for all the help!
John Ullom
