Will do. Also on the antenna side I am planing an upgrade.
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I had the same challenge before i moved. There i had the antenna in the attic. For testing i put it outside the house and had surprisingly the same reception. Seem to be that the roof didnāt block signal that much.
Make sure you keep the cable as short as possible and use a good one.
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Now with the 1090 uputronics there is quite some improvement. Next step is to optimize the airspy_adsb parameters and for this I would appreciate if someone could elaborate a bit more on them because ā-hā only shows some minimal info. E.g. how quickly is āauto gainā reacting? What is the difference between RMS and SNR mode? Is there no documentation available?
Another important question is how critical the max. temp of 40 degrees is as in typical setup this might be difficult to achieve, even with an attached fan in a closed outside box.
https://github.com/wiedehopf/airspy-conf
That is the extent of the documentation.
There is tons of discussion in this thread but itās hard to search.
autogain reacts very quickly but iād have to look at the source exactly how quickly ā¦ probably 1 gain step per second or something like that.
But i prefer just running one gain setting as it makes it easier to see changes in the graphs.
The airspy has enough dynamic range so some quick acting autogain isnāt really necessary.
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Thank you for your reply - ~1 gain step per second is more than enough to react if a signal is coming close to the receiver (e.g. landing aircraft). So if I understand you correctly, you are providing the binary and it is not open source?
I had it running in a closed box with a Raspberry 4B over last summer where temperatures reached 35Ā°C outside. The Raspberry SoC was at around 65Ā°C.
I didnāt measure the Airspy stick, but it was too hot to touch. However, it did not fail a single minute.
Some users have attached heat sink to it, documented also in this thread:
I have autogain running on my receiver and find that in practice the gain only really changes with overall traffic levels. During the day itās almost always at 15 or 16 and usually stays on the same value all day. At night the gain goes up to 18, and occasionally dips a level or two if thereās a period with more aircraft in sight.
It doesnāt jump about when thereās more than a few aircraft visible though, so Iām happy to let it sort itself out.
Same is shown on my device with different values. Over the day it goes down to 19, but stays there for the entire day. During night with low traffic it comes up to 20 or 21, but overall the number of changes is less than five.
Iāve helped improve it but in the end itās still Youssefs code which he prefers to keep private.
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There was no need to have it react better like the new readsb autogain.
Thatās just due to how the airspy deals with very strong signals, it will give data that can be decoded even beyond what you would expect for the ADC dynamic range.
At least for ADS-B with its very simple modulation.
On rtl-sdr you get frontend issues with strong signals before the ADC is even at maximum.
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In the airspy_adsb config file, currently have -f 1. If I change this to -f 0, will it be less taxing on the pi? Landing page says cpu usage of 85% on the pizero2w but I have no idea if thats on the limit, hence reviewing a few options.
Also, I notice I dont use the -e or -E options - am I missing something?
This is a big thread - but useful. Around #865 an example configuration file is shown and discussion around that time, center on setting -e to 9.9 or 10. I see currently -e can be between 1.0 and 60.0. Any advice for setting of the -e ? Is a number closer to 60 better?
https://github.com/wiedehopf/airspy-conf/blob/master/airspy_adsb.default
https://github.com/wiedehopf/airspy-conf
Thank you. I did have a theory which I thought Iād run past people.
As āotherā positions are not so important I had two thoughts. Setting -f 0 should mean less āotherā positions, leaving the pi to potentially gather more legit positions. Although setting -f 2 may mean more āotherā positions but the correction may result in more corrected positions. Which of the two settings seem more plausible for resulting in more legit positions. I was thinking -f 0, but figured I may well be wrong.. This is on a pizero2w, although could the answer be -f 2 when running on something more powerful?
Running the defaults airspy-conf uses would be out of the question i assume?
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Running pretty much default, just the e E and P which I donāt know much about. Guessing the auto gain is the ideal setting.
larger -e uses more CPU.
The defaults automatically adjust -e up to -E to use up to -C percent total CPU usage.
There is short explanations in this file:
https://github.com/wiedehopf/airspy-conf/blob/master/airspy_adsb.default