FlightAware Discussions

HOWTO: Airspy mini and Airspy R2: Piaware / dump1090-fa configuration

@Hampstershorts,
I use the Hab/Nevis/Uputronics amp with a cavity filter between it and the antenna or the rtl-sdr amp(again with cavity filter). I have so much noise in my area that I need cavity filters. I must test the airspy with just the rtl-sdr amp/filter without the cavity filter some time. I remember testing the hab/nevis/uputronics amp years ago and it had to have the cavity filter(using rtl-sdr, airspy or radarcape). I have heard reports that the rtl-sdr amp/filter is a bit better in noisy environments. I may be able to put the cavity filter between the airspy and amp. They are close enough I can run a USB cable to power it.

Jon

I am using the RTL-SDR ADS-B LNA which could use up to 150mA. Considering the Mini has a bias-tee with a 50mA limit would that cause the dongle to shut down?

I didn’t realize the Mini was only 50ma bias-t rated. Thats a huge problem. Power that bad boy through other means or you’ll wind up with a useless $100 radio in no time.

The whole USB port has 500mA capability. Maybe less on the Pi3.
So anything that needs to be fed-trough will deduct from that amount.

Considering that the outside LNA can fail in a short-circuit state, I never trusted feeding them from a $99 (or $169 in my case with R2) receiver.

Raspberry Pis don’t particularly follow the USB power standards. There is no 500mA limit per port, rather there is a total allowable USB current supply of 1.2A for the Pi 3 onwards. This total is for all ports, but can be drawn through any single one. The Pi 2 had a 600mA limit but was software switchable to 1.2A.

Ya I don’t get it. I have a Pi 3B+ with only the Mini plugged in in 12MSPS mode. It shouldn’t be a power issue unless my Pi board itself has a problem. I can run a Nooelec dongle with a built in bias-t with no problem. I’ll try an external bias-t I guess. Unless my Mini has a hardware issue.

Just as a follow up, I received an external bias-t and the problems I was having with the Airspy Mini stopped. It must have been an issue with pulling too much power from the internal bias-t in the Mini.

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On another note, is there any benefit to pointing other feeders at port 47787 that the auto script sets up for airspy_adsb instead of port 30005 that beast-splitter is using? Is beast-splitter forwarding everything coming out of airspy_adsb verbatim? Can airspy_adsb handle more than 1 connection?

Airspy_adsb can. Not sure about CPU though on slower RPI 3s and 4s.