Mumbai, Nov 21 (IANS) Amateur radio operators, also known as ham radio buffs, in Mumbai were baffled by unidentified mystery signal transmissions reportedly originating from the Arabian Sea on the country's west coast, an operator said here on Monday.
Though the signals have been picked up by their VHF wireless radios since the past five months or so, they became suspicious after they tracked them down to the deep sea off Maharashtra-Gujarat coasts, said Ham Radio Operators Mumbai spokesperson Ankur Puranik.
"We have written to the Wireless Advisor, Ministry of Telecommunications and IT, with copies to the PMO, other ministries, and top defence and police officials to take note and investigate these unknown signals," Puranik told IANS.
They sent the memorandum to the Centre after analysing the signals with their direction-finding equipment and antennae and were alarmed to learn they originated around 100 nautical miles in the high seas off the Maharashtra-Gujarat coast.
"They are encroaching on our allotted bandwidth 144-146MHz for our two-way radio, they don't use the compulsory 'call sign' by which each ham radio operator in the world can be identified and tracked, and they speak in a language we can't understand," Puranik explained.
The amateur radio operators did not rule out the wireless signals originating from some anti-social elements or sea pirates or other groups with possible nefarious motives.
Around 70 of the 200 amateur radio operators in Mumbai have heard these unknown signals at various times of the day, and mostly at night and they still continue.
Puranik claimed that the unidentified operators could be using high-power wireless sets in the range of 25Watts-50Watts and their signals may be propagated many hundreds of nautical miles to other Indian coastal areas or some neighbouring countries.
"We believe that they are using open-band wireless sets which can tune in to or transit in any frequency in the VHF band between 136-174MHz. Some of these frequencies may be falling in the bands used by the Indian government and security agencies," he said.
In the memo, they have urged the Centre to check out dealers of Marine Radio Equipment in India and the radio licences of all fishing vessels to ascertain if the mystery operators have acquired their equipment from illegal sources.
Besides, they have also drawn the Centre's attention to the unauthorized sale of two-way radio sets on various online sites, shopping sites and other internet marketing outlets which are flouting Indian laws.
