To improve performance:
Place mag-mount antenna close to a window.
Place mag-mount whip over a food can.
The whip is too long. Its optimum length is 1/4 wavelength, which at 1090 Mhz is 67mm. Unscrew the whip of mag-mount, and replace it by a 67 mm length of thin steel tie wire.
Piaware doesn’t seem to require much processing power. I understand that it all depends on the rate of received messages, and right now I don’t have a high message rate. A RPi is plenty adequate for this application. As “obj” mentioned, running on bare metal (as opposed to a VM) would reduce latency and particularly jitter, so the possibility of dropped USB data would be reduced. This is a good example of why IoT (or “edge computing”) is such a hot topic. A dedicated inexpensive processor can do a lot of useful tasks, like receive ADS-B messages and perform MLAT calculations (UPDATE: Local RPis don’t do MLAT calculations… see discussion below). I’d be interested to know how flightstats aggregates all the ADS-B receiving station feeds. Do they have some edge gateways, or do all the feeds just go directly to a central server?
@curtko,
Note that the RPI does not do MLAT calculations. The MLAT servers at FA, do it and feed it back to the RPI’s MLAT client.
Note that an old RPI1 can cope with a lot of traffic. An RPI2 should be able to cater for the busiest environments. Not sure if we will get a new version of the Raspberry Pi at the end of the month or on Pi day next month(The Raspberry Pi’s typical announcement dates over the last few years).
I use my RPIs for cacti/mrtg, APRS, ADS-B and soon maybe AIS and netflow
Cool, thanks very much for the info. That’s good to know about where the MLAT calculations are done. That makes sense, of course. The local RPIs don’t have access to other RPIs, no matter how “nearby” they are. This is something that would be a good function for an edge gateway, though.
I think I will wait for March 14 to see if there will be some new RPis coming out. Although at the current pricepoint of the RPI Zero W, it’s practically disposable. And as you said, even the RPi2 has more than enough processing power for piaware, so the current generation is just fine.
If you are planning to use something like an Airspy mini, you will see that the Pi2 is not enough. Even the Pi3 will struggle.
Thanks, that’s good to know. I haven’t decided yet on which SDR to get. Probably for this application I’ll go w/ the FA USB dongle. If I get the Airspy, it would be for general SDR use.
Thrifty solution:
Pi Zero W, generic DVB-T stick, DIY antenna Spider, Quick Spidet, or Cantena with RG6 cable.
Better Solution with moderate cost
Pi 3, Flightaware ProStick Plus (blue), Flightaware 26" / 66cm antenna, LMR200 coax. An external filter may improve reception if your enviroment has strong ce phone signals.
High end, high cost solution
Professional dongles / receivers with professional filters and professional antenna and high quality low loss coax.
Thanks, “abcd567”. I am probably going w/ some combination of your 1st and 2nd options. I must say that I enjoyed an earlier discussion thread (long!) on this forum about home-made antenna designs. You guys are quite a crafty bunch. Do you ever get together for face-to-face meetings? I imagine that would be difficult, as you have contributors and ADS-B station operators all over the world. This forum is definitely a great resource. Thanks to all of you.
If you are going to use Flightaware 26" / 66cm antenna and ProStick, you will need cables and pigtails shown here:
If you are going to use DIY antenna, and RG6 coax to connect DIY antenna to Dongle, you will need one of the following two pigtails at dongle end:
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I managed to get piaware running on Ubuntu using Fusion on a Mac as well as VirtualBox on Windows 10. It was easier to set up on Fusion (mainly because I’m more familiar with it), but it works well on VB also. It was mainly a matter of installing all the dependencies on Ubuntu, but this is well documented in the README for piaware_builder (piaware_builder/README.md at master · flightaware/piaware_builder · GitHub).
