When I get asked ‘what is ham radio?’ I generally get a bit tongue tied and waffle on a bit. There is nothing harder as a ham than actually defining the hobby. This is really down to how diverse the hobby is. Fundamentally at the core is a like of RF. Other than that it sort of sprays out a heap of sub genre’s that have a variety of different followers. Amateur TV, DX chasing, GHz…. the list goes on and on. Perhaps one day a map will be available that shows the full spectrum and a few of the relationships, but for now here is another one. I’m going to call it ham radio services as a working title, it is defined as the ham who uses his knowledge and equipment to provide a service based on RF. APRS igates are an example of this.
So what else is there? The Raspberry Pi has certainly opened up the opportunity to provide low cost services. I have one the is an APRS igate, one that runs my SatNOGS ground station and that was it until last week when I put an unused older Pi2 to good use as an ADSB receiver using a system called PiAware. Essentially a way of melding together an RPi, rtl-sdr dongle and an ADSB antenna. All so that it can listen out for the aircraft beacons and report positional information to the Flightaware website.
The ‘project’ took no more than a couple of hours, mainly because my Micro-SD card died and I had to scrabble around for another one. It is very simple to do and will put your Raspberry Pi to good use. Steps are summarised as
- Sign up with the Flight Aware website and read through the docs on the PiAware page
- Download the image
- Burn the image to a (non corrupt) micro SD card. Plonk it in the pi
- Plug in an Rtl-sdr (or you could splash out on a Flight Aware Prostick)
- Power on
- Find IP address of RPi on network (look in the router settings)
- Go to site (mine is 192.168.1.100). You should have a screen that looks a bit like this
- Claim you receiver (Instructions are on the screen). There will be a link in the place where it says ‘View your site statistics online’
- Sit back and watch the packets come in. When you’re ready go to the FlightAware website and see how well you are doing.
Looking west is best as always from my QTH. Where’s the fun in that? I hear you say?
Its good to experiment, after all there is DX to be had, just not in the conventional sense. Lets take a comparison between WSPR and ADSB. A bit off beat but here goes, WSPR will tell you the distance and signal to noise of your station as heard by another, DX, station. You do the transmitting and someone else does the receiving. With the PiAware setup someone else does the transmitting and you do the receiving. Is this not the same thing? A different band ok but actually the same thing.
Beats attempting to get in contact with some short lived station in a rarely activated location by shouting into a microphone for hours on end. Say I. Wouldn’t it be boring if we all liked the same thing.
One final note. There are lots of RTL-SDR dongles to choose from. The cheap £3 ones from eBay work, they are reliable enough and coupled with the (normally) supplied antenna give me a range around 150-200 nautical miles. the Pro Stick mentioned earlier will extend that range by using a broadband low noise amp (LNA). If you live in an urban environment you can use the Pro Stick Plus that comes with a band pass filter or add in your own. you may also need to adjust gain settings and have a play. I am only using a wire antenna, I will find a reasonable supplier for a colinear or similar and report back.
Onwards and upwards