I thought you ham folks might find this interesting
A satellite launched by the US military has gone rogue and is causing interference to radio hams across Europe.
The US Navy’s PCSat NO-44, which is only supposed to transmit over the US, is now drowning out European amateurs and the USN doesn’t know what to do about it.
Former head of information security at BT and keen radio ham John Regnault got in touch with The Register to explain the problem.
Licensed as an amateur satellite in the Amateur Satellite Service, PCSat was launched 30 September 2001 from the Kodiak Launch Complex on Kodiak Island, Alaska aboard Athena I.
It was designed to be a worldwide position, status reporting and message communications satellite for remote travellers. The satellite is on a tight polar orbit and passes over Europe every hour or so.
It uses the APRS (Automatic Position Reporting System) protocol to permit hundreds of users per pass to access the satellite. To demonstrate this concept, PCSat augments the existing worldwide terrestrial amateur radio APRS tracking system by providing links from the 90 per cent of the Earth’s surface not covered by the terrestrial network, so when it passes over it drowns out other users of the frequency.
The spectrum it interferes with is around 15 KHz, and generally used by radio amateurs for meteor scatter, sending short text messages over distances of up to 2,000km by bouncing them off the ionisation caused when a meteorite breaks up in the atmosphere. The last thing a radio ham wants is to wait for a meteor shower to send a message and then have it drowned out by a passing satellite.
Now redundant, PCSat NO-44 should be dead, but isn’t. This is because it is designed to use more power than it has on board – a negative power budget – and then reboot when its solar cells generate enough power to wake it up. Robert Bruninga of the US Naval Academy, posted to a Usenet group to explain the problem: