KARACHI, Oct 8: The high-frequency radars used by the ships in the Arabian Sea have started interfering with the communication signals emitted by the satellites orbiting the earth, Dawn learnt here on Monday.

Cable operators said that shortly after the Sept 11 terrorist attacks in the US, their satellite equipment started receiving signals with an appreciable time-lag, causing frequent “communication hiccups”.

Khalid, a cable operator in KDA Scheme 1, said that all too often communication signals being emitted by the satellites having different frequencies “blinked”, forcing the cable operators to re-track channels.

“Though almost all the channels have been hit by the waves of the radars used by the ships positioned in the Arabian Sea, BBC, CNN and StarPlus are most affected,” he said.

An official of the Cosmos, a cable operator in the Defence Housing Authority having more than 5,000 connections, said: “The problem of distortion/interference will persist as long as there are high-frequency radars on the ships in the Arabian Sea.”

A cable operator in Federal B. Area, Naeem Ansari, told Dawn that he had no idea who to lodge his complaint with. “We are registered with the Pakistan Telecommunication Authority, but we are sure that even the PTA will not be able to ensure that signals emanating from the radars on the ships in the Arabian Sea do not interfere with the communication signals emitted by the satellites,” he observed.

A large number of TV viewers told Dawn on Tuesday that they had had experienced frequent shutdowns of cable transmission over the past few days, especially during the early hours of Tuesday when US forces pounded more than five cities of Afghanistan.

A communication expert told Dawn that the interruption in cable channels transmission was due to ”cryptographical software-hardware problem”.

He said geo-stationary communication satellites operated in three bands: C-band (4-6GHz), KU-band (10-14GHz) and KA-band (16-20GHz). He added that, as a rule of thumb, the satellites which were used for military purposes operated in X-band, KA-band and V-band, having almost the same frequencies as communication satellites.

He, however, observed that the interruption was not due to interference but due to the fact that communication signals were not being properly decrypted due to the radars being used by the ships in the Arabian Sea.