Some readers might wonder how different satellites manage to operate almost alongside one another in space but avoiding transmission interference. The answer is in the – usually – pre-agreed harmonisation of frequencies and their target audiences.
A perfect case in point is a major dispute between Arabsat, and its satellites operating from 30.5 degrees East, and London-based Avanti Communications, which is about to launch its Hylas 3 satellite to 31 degrees East. In orbital terms this is absolutely next door to the Arabsat craft.
Worse, both satellites are arguing that ‘their’ Ka-band transmissions are the rightful occupiers to the slot, and hold priority rights to transmissions.
Arabsat’s 6A craft, which now sits alongside Arabsat 5A, was launched in April. Hylas 3, already extremely late in its launch schedule, is likely to be orbited on July 24 by an Ariane 5 rocket.
Arabsat says that its Ka-band transmissions were “brought into use” and thus gained priority, in 2010.
However, there’s a problem. Avanti, along with the UK’s telcoms regulator OFCOM, say that Arabsat has failed to register its Ka-band plan with any of the formal registration organisations. Arabsat says, perhaps cheekily, that because its use of Ka-band is for “military usage” it did not have to register (Arabsat invoked the ITU’s ‘Article 48’ which specifically says that military services do not have to pre-register).
The past months have seen meetings take place between Arabsat and Avanti with the ITU’s Radiocommunications Bureau, but – to date – there has been no agreement. The latest meeting took place at the end of June, and while there was plenty of goodwill, the only agreement that emerged was that both satellite operators will attempt to identify service areas which their beams will reach, but without interfering with one another.
Arabsat is targeting North Africa and the Mid-East, while Avanti’s main targets are sub-Saharan Africa.