Three
weeks back, we presented Part 1 in a mini-series of topics on the radio scene
in Madras-Chennai with particular reference to the inroads of the recent
disastrous Cyclone Vardah. This brief
topical series was researched and written by Jose Jacob VU2JOS in Hyderabad
India and it includes information that was gleaned during a visit he made to
the station a few years earlier. Last
time in Part 1 here in Wavescan, we presented the story of the shortwave
station at the three part transmitter complex at Avadi where one of the antenna
systems was felled by the high winds of the recent cyclone.
In our program today, we present the
story of the two other stations located at this three part transmitter complex
in Avadi. The shortwave station is the
first that you will encounter as you enter this large radio complex, and in our
program today we move on to Transmitter Building No. Two.
Avadi Transmitter Complex: Building - Mediumwave
As Jose Jacob reports: A second transmitter building is about
half a mile away from the shortwave building.
In this building there are two 10 kW BEL HMB163 medium wave
transmitters which were commissioned on October 14, 1994. These two units operate on 783 kHz with
Vividh Bharati programming on a down link satellite relay from Mumbai-Bombay.
Next
to these two 10 kW transmitters is a 20 kW Harris DX20 medium wave
transmitter operating on 1017 kHz with B channel programs from the AIR studios
in Madras-Channai. This third
transmitter at this second station at Avadi was commissioned on October 17,
2001. Back in 2001, a mobile BEL 10
kW transmitter was in use here temporarily while the Harris transmitter was
under installation.
Interestingly
the signals from these transmitters that are assigned the two frequencies 783
kHz and 1017 kHz are diplexed into the same self radiating mast antenna at a
height of 300 feet. Up until 2001, an
NEC MB124C was in use here on 1395 kHz as the AIR B Channel, and this unit was
moved to the A channel building complex to be used as a standby for the main
transmitter. There are also standby
generators in this building.
Avadi Transmitter Complex: Building - Medium Wave
Less than a quarter mile away from Building Two, is the third
building, in which the original transmitter, a 20 kW BBC SM42A3 mediumwave unit,
was commissioned on January 11, 1956.
At first it used to operate on 940 kHz but shortly afterwards it was
changed to the present channel of 720 kHz. This transmitter was dismantled in
the mid 1990's.
Currently in this building, there are two medium wave transmitters
at 100 kW each, both BEL model
HMB140 operating on 720 kHz. This
double set of transmitters replaced the earlier 20 kW BBC medium wave
transmitter that was commissioned thirty one years earlier.
There
is also a 10 kW NEC MB124C transmitter here in Building 3 that is in use as a
standby unit.
It was previously in use in Building 2 for a period of seven years and
it was transferred to its new location in 2001.
There is a standby generator for this 10 kW NEC
transmitter, too.
Avadi Transmitter Complex
Because the Avadi transmitter site is near
the coast of the Bay of Bengal, they use directional antennas to beam their
programming within the Indian mainland. For this reason, the main self radiating tower
is 485 feet tall with a nearby reflector tower 400 feet tall.
Programming on five channels from
the AIR studios in suburban Mylapore is received by a
studio to transmitter link on 1440 MHz, though some programs are also received
by satellite. The original Mylapore studios were
inaugurated on April 13, 1969.
In
the entire three station site, says Jose Jacob, "I could see more than 15
towers. Several cows were grazing under
the antennas, maybe to bring down the grass.
The staff uses Motorola walkie talkies throughout the site".
At the time of my visit in 2004, the security personnel and others were
seen using transistor radios and wired speakers and they were listening to
their station keenly while it was giving the results of the Indian General
Elections.
(AWR-Wavescan/NWS 415)