Sunday, March 8, 2015


The timing of our visit could not have come at more depressing times for a DXer. Radio stations all over the world were closing down and Voice of Russia - the erstwhile Radio Moscow - a mega power house of the Cold War days had just closed down its radio transmissions. South Asian DXers were still reeling from the shock of closing down of 
DW from trincomalee sometimes ago. Our visit was significant against this gloomy backdrop.

Here was, however, a silver lining for the radio aficionado. AIR Chinsurah had just commissioned a brand new solid state super power MW DRM capable transmitter in 2013. The 3 x 400 kw DRM capable facility was still undergoing tests while the privileged five DXers of the IDXCI got a chance to visit the facility. The visiting team of DXers was mix of young and old. There were DXers in this team with first QSL of 1967 to the youngest whose first QSL was in the late nineties. All of us had seen receivers from the RCA AR 88 of the world war days to modern SDRs including the SDR dongle!! But never had we visited a solid state MW super power transmitter. A super power transmitter in our mind still had the picture of a workshop

floor - cables, pipes, dust and grease all over (see our article on AIR Kolkata at Amtala and Chandi). This was definitely different!! As we entered the Transmitting facility 40 km away from the heart of Kolkata in a summer afternoon, there were flowering "nayantaras" greeting us. This was not something you would expect in an All India Radio station. This facility was first built in the mid nineteen sixties with Russian transmitters and antenna. It was later upgraded to a 1000 kw MW facility which beamed AIR external services to neighbouring countries and the south east Asia on 1134 or 594 kHz. 

 In 2013 a brand new Thomson s7hp 3x 400 kw facility replaced the old Russian transmitters. However, the old Russian antenna and the feeders were retained. Retained would be an understatement because the antenna and feeders were so thoroughly overhauled that they looked perfectly matched with their smart young French counterpart – the transmitters from Thomson. The high antenna tower in front of the Transmitter building still had an Yagi put up on its top . It was from the days when the link from Akashvani Bhawan at Eden Gardens Kolkata was via the FM link. This link began to falter many years ago when high rise buildings began to appear in the line of sight and often made the link unreliable. Today there were satellite links via a huge TVRO dish besides the T2D2 cable link . The old transmitter building from outside had remained the same with repairs and bright new coat of paint. As we climbed up the stairs the sign board “ “Super Power Transmitter, Chinsurah" greeted us.

We soon entered into a sparklessly clean white tiled large hall with few monitors on a table in the centre of the hall with chairs around. On one side of the hall were the transmitter panels some of them looking like innocuous almirah doors. At the center of the hall were flat monitors and key boards. The monitors were the control panel for this mighty radio horse. We next entered the transmitter area through the entrance in between the panels. No tubes or thick copper tubes running around. The power section of the transmitter were banks of FETS all neatly stacked. Rather than the tubes blowing up as with the tube transmitters, the solid state transmitters have to face blown up FETS. The corresponding FET panel s will then have to be replaced. The engineers seemed a little concerned over the limited inventory of FET spares. To open the enclosure of the FETS there were interlocking mechanisms. The key for the enclosure will

 be available only when the power supply has been switched off. The output RF signals were fed into a an unit which has been locally assembled. It switches the signals to the one of the four large antennae and also switches between the frequencies. . We were quiet impressed by the switching system and looked around. It was a far cry from a Dxer switching into one of the many antenna through jumbled wires at the back of his receivers !!

 We were next taken on car ride through the antenna fields to the antenna. There were two omnidirectional antenna on one side of the vast antenna field . There were the directional antenna on the other side of the field which threw signals to the east and north east asia. At the moment only the omnidirectional antenna was being used. The feeder lines were impressive. There were very robust coaxial lines supported on concrete cement rings on cement posts placed regularly. They were all overhauled thoroughly. Each post had mechanisms for matching the feeder lines and this could be operated by remote control . For us Dxers strolling in the antenna fileds amids feeder line support post was like taking an evening walk in a exotic hill station !!!As we stood at the base of the antenna mast we were struck by the majesty of the antenna masts standing tall !!!

 Back at the transmitter building we next visited the power supply area. This was on one end of the elegant transmitter hall. There were very large backup power supplies for the transmitters. They were all controlled by the computer. One of the major transmitter breakdown was once due to the failure of the computer controlling these power supplies. The genset at the first floor of the building was modest and was designed to supply the entire facility in the event of a breakdown of power supply. Ever since the tubes transmitters gave place to the solid state transmitters the power requirement had dramatically come down. There was a saving of several lakhs of rupees each month on account of this power savings.

 As it was nearing 5 pm local times, the engineers set about charging two of the three transmitters for the evening transmission. It was all done trough few mouse clicks. We sat starry eyes as one of the transmitters refused to start and all that was showing were few red blocks flashing in the screen. The transmitters were carrying program for the AIR Kolkata A which is the main radio channel in this region. The old
 channel 657 was also there but had been faltering for some times now. This channel was
the backup programming. What about DRM ? That will be in the next phase. We Dxers understood because not many us had been fully equipped with robust DRM Receivers. However, these brand new solid state super power babies are a very welcome addition to the dying family of AM radio transmitters.