Thursday, June 09, 2016

What's inside an SDRPlay

I love tuning around HF with an SDR display, it's great to see the whole band in one go.

The recent v0.1.20-alpha update to CubicSDR works very well on MacOS and in particular with the SDRPlay. These things just look like a black plastic box and I haven't seen any pictures of the internals so here you go:

As you see not much there, but it has 8 automatically switched input band pass filters. Full technical information is here.

It interfaces with SDR software via SoapySDR:

And works really well.

Sunday, June 05, 2016

ADS-B Plane tracking with RTLSDR and Raspberry Pi

It's raining this weekend in Sydney so it's a good time to tinker with things indoors. Thanks to Ross, VK1UN for the tip, I'm now able to receive the location beacons from planes and plot them like this:

ADS-B transmits information about a plane and its position and speed on 1090MHz.

The hardware is a Raspberry Pi 3 and a low cost RTLSDR dongle. The software provides both a terminal live listing of what's been received and the amazing map you see above (which updates live).

Excellent instructions are here. All credit to David & Cecilia Taylor for the excellent job. I'm not uploading any data but rather am just watching what I can receive locally.

The command I run to produce this is:

./dump1090 --quiet --net --phase-enhance --net-http-port 8080&

And then I forward port 8080 from my router to the IP of the raspberry pi.

To run interactively on a terminal do this:

./dump1090 --interactive --net --phase-enhance

On the terminal you get a text version like this:

I found that the Terratec RTLSDR didn't need a powered hub on my pi which is powered from a modern iPhone charger. The antenna is the small TV vertical just sitting near a window facing south and it works amazingly well.

Ross, based in Melbourne, has been making co-linear antennas from coax and is doing much better than me at receiving both numbers of planes and distance. Check this out:

Update: Dramatically improved antenna

Under the direction of Ross, VK1UN, I've built an improved external co-linear antenna.

I'm using RG6 75ohm coax. The segments are 11.2cm long cut like this:

The segments are pushed together simply by pushing the centre of one under the insulator of the next.

The antenna is on the balcony pushed up a plastic pipe.

Previously the furthest plane I could receive was about 85km away, now I've seen planes over 300km away. I'm also seeing more planes.


I've neatened up the antenna by purchasing some 25mm pipe and an end cap - about $5 all up.