There is a lot more to satellite monitoring than just watching television from around the world. Why not take a break from the usual satellite television offerings to monitor air traffic (in Australia) via both satellite and microwave.

ATC circuits on Optus B1

Optus B1 is a KU band satellite positioned above the equator at 160 degrees east. Optus B1 is best known for it's use as the primary satellite for Australian outside broadcast and raw studio feeds. Optus B1 is also the satellite that is used by SBS and the ABC to feed their terrestrial transmitters with programming around Australia. However there are many other services available from Optus B1, one being Air Traffic Control (ATC) channels covering flights all across Australia.

You will find the ATC on the horizontally polarised beam and it is dead easy to tune into the signals using a regular UHF radio scanner connected to a suitable dish. ATC channels are found as Narrow Band FM signals between 980.000 MHz and 1015.000 MHz (when using an LNB with a 11.300 LO output frequency). Channels include en-route, approach, ATIS (Automatic Terminal Information Service), VOLMET (Weather broadcasts), chat between controllers regarding traffic handoff as well as relays of the HF frequencies used when aircraft are flying across the Pacific & Indian oceans etc. ATC for all of Australia is heard, there are literary hundreds of channels.

I have set up a dedicated dish for ATC monitoring at my shack with a PLL LNB/Feed connected to an 18 Volt power supply, the coax cable then directly feeds my scanner. If you already have a satellite TV receiver on Optus B1 it's very easy to connect a scanner to your dish! On the back of most receivers there is an LNB out port (sometimes called loop through) you connect a coax cable from here to your scanner. Using your receiver tune up any Optus B1 Hz television channel and then move across to the scanner. Now tune between 980.000 MHZ and 1015.000 MHz and you will find the signals. You may wish to use a non-power pass splitter, to protect your scanner input from the 18V on the coax that is used to power the LNB. Most receivers don't pass the LNB power voltage through the LNB out loop through port, however if your not too sure about your receiver, a non-power pass splitter will ensure you don't damage your scanner front end.

On Satdirectory's support page you can request a copy of a Microsoft Excel spreadsheet file which lists ATC frequencies on both Optus B1 & B3 with notes on what I have monitored on each channel. When looking at my log you will find both "Night" and "Day" frequencies listed. This has nothing to do with the satellite transmitting frequency (as far as I know) but more to do with my LNB drifting as the air temperature changes. Almost certainly you will find that the frequencies on your system are different to my log. The LNBs we use to watch sat TV were not designed for this narrow band FM work, and so they will drift and also give a slightly different frequency output dependent on model & brand.
When first using the spreadsheet I would recommend you tune up an ATIS frequency - for example Hamilton Island on Optus B1 990.770MHz. This frequency gives a continuous report of conditions at the Hamilton Island Airfield (ATIS = Automatic Terminal Information Service). Can you hear it on 990.770? Chances are you can't due to differences between my LNB and yours, so tune slightly up and down the band till you find it. Once you have found the ATIS you can add a column to the spreadsheet with "your" frequency. Calculate the difference between the frequency where I hear the ATIS and where you have heard it and then you can apply the correction factor to each frequency in the spreadsheet.

Satdirectory provides a live feed of air traffic control via the Optus B1 satellite 24/7.

Tune in to the feed on:

Satdiectory's live ATC feed is hosted by the world's leading source for air traffic control audio and information

Two Melbourne Centre sectors are being  scanned and presented as one audio stream. The first sector includes the high and low airways over Central Australia including A576, A461, T29 etc. You will hear aircraft flying between Asia and Melbourne/Sydney on this sector including aircraft on the ground at Ayers Rock, Olympic Dam etc. The second sector feeding is a sector covering Western NSW (a state of Australia) where you will also hear international and domestic aircraft on T74, A576, G222, J141 etc.

Virtual "radar" of civil airspace

Monitoring air traffic control is a particular passion of mine! What has really added a new dimension to my interest is the reception and decoding of aircraft Secondary Surveillance Radar ADS-B mode signals on 1090 MHz. ADS-B is a signal that gets modulated on top of an aircraft's transponder Mode S signal. Providing more information than the bare transponder, the ADS-B signal includes data that allows the decoding of the aircraft's position in latitude and longitude, altitude, heading and vertical speed. Also reported is the aircraft's flight number  and the airplane's unique identifier, which in turn enables suitable software to figure out the airplane type, owner and registration from a database.

Most international airlines that have aircraft in their fleet that regularly fly into the US or Europe have their planes equipped with ADS-B. These aircraft are easily received with a suitable receiver and software program when they are in range of your antenna (up to 250 nautical miles). The majority of Jetstar and Virgin Blue aircraft transmit ADS-B signals, however at this stage only the newer aircraft in the Qantas fleet (737-800's and Airbus A330's) can be tracked. ADS-B will become mandatory addition to both general aviation and airline operated aircraft probably around 2009, so as time goes on the volume of traffic displayed will increase.

To give you an idea of a typical ADS-B virtual radar display that you can display with real-time data examine the captured a screenshot on this page. Jetstar A320 VH-VQK is on final to runway 16 Right at Sydney. The "data tag" on the aircraft advises that the aircraft is Jetstar Flight 623 coming in from Maroochydore. At the time I took the screenshot the aircraft's speed was 119 knots (ground speed) and at 650 feet (based on standard QNH). Virgin Blue Flight 559 is north-east of Mudgee while a China Southern Airbus A330-200 is climbing through 19,000 feet and just about to pass over the Richmond Airforce Base.

To sample an example of a typical ADS-B display have a look at Balthasar Indermuehle's excellent real-time stream of air traffic over Sydney.
Virtual Sydney "radar" display created by using ADS-B data on 1090 MHz
Satellite and microwave monitoring of Australian Air Traffic Control 
Phased-Locked-Loop (PLL) LNB for monitoring ATC on Optus B1
90cm offset dish for monitoring ATC on Optus B1
1090 MHz antenna for receiving ADS-B data direct from aircraft
article update

Since this article was published the Optus B1 satellite has retired. The Air Traffic Control radio circuits are now found dispersed across Optus C1 @ 156.0° East and Optus B3 @ 152.0° East. The ATC transmissions are received from these two satellites by using the same techniques described on this page.  This article with it's references to Optus B1 remains at for both reference and historical purposes.