On one fine day sometime in 1950’s, my father asked me
whether I was interested in accompanying him, for a visit to a radio station
near Daund town, about 40 Km from Pune city located on Pune Solapur Road. I was
just a school going lad and had never heard before about any radio stations or
any associated stuff. We had an old Westinghouse Radio receiver in the
house. This radio was mainly used to
listen to news and occasionally music programmes. Pune had no radio station,
and we only could listen to Mumbai A and B stations. However, since this trip
would mean a long ride on the motorcycle, I immediately said yes! And we were
off on Solapur Road on the AJS 350 motorcycle belonging to my father.
About an hour later, we reached a medium sized single-story building somewhere near Daund town. Apparently, my father knew the engineer in charge. He welcomed us and took us to a large hall in which number of large black-coloured cages could be seen. In each of these cages there were several radio receivers with many more controlling dials than our old Westinghouse radio at home had. The engineer told us that these cages are called Faraday cages and used so that radio receivers only receive signals from antenna and not spurious ones. Some of the receivers were connected to paper punches punching holes on paper tape rolls fixed on sides. Some of the other receivers had only outgoing cables. The engineer explained that the receivers with paper tape rolls are receiving international radio telegraphic messages or wires (तार) and were being recorded in the punched tape form. Later these spools would be run on the regular P&T telegraph machines connected by telephone wires to Mumbai, and all messages or wires would be forwarded to Mumbai for further distribution. The other receivers were receiving only downlink conversations of international telephone calls, and these were directly being forwarded to Mumbai. To demonstrate this, he just plugged headphones in one of the jacks on receivers and we could clearly hear only a humming sound. The conversations obviously were being demodulated in Mumbai and us at receiving station had no idea who was speaking with whom.
All receivers were connected by cables to antennas erected at the outside. There were tall seventy- or eighty-feet high steel towers standing with wires connected in between them and receiver cables received signals from there.
The engineer also told us another interesting byte. He said that Daund receiving station is only connected through a place in Britain and then to London. All international wires or calls are routed through London. This would mean that even after independence, we were still part of empire network.
For a school going lad like me, this visit turned out to be
an eye opener and probably began my fascination for Electronics. Something I
still carry even after seventy long years.
I was curious and asked the Engineer uncle, that I have understood what
you do here but do not see any outgoing cables or calls. He laughed and told me
that to see that I would have to visit Beam wireless station at Dighi, again
near Pune, on some other day.
Not much later, I had an opportunity to visit Dighi beam wireless station also, along with my father. They wanted some RF meters and wanted to discuss that. Trip to Dighi turned out to be much shorter as it was not very far on Pune Alandi Road. In Dighi, the transmitter was set up in a similar building but with a very high ceiling. The transmitter was in two parts in adjoining rooms. One room had large vacuum tubes in glass shell with filaments that looked red hot. These vacuum tubes were connected to actual transmitter sets, kept in the other adjoining room. Here punched paper tape spools turned and fed data to transmitters at a very high speed. There were also some transmitters by which uplink conversations of international telephone calls were transmitted. I saw that most of the equipment here was that of Marconi make. The transmitting tubes were connected to a cable which ran outside. Two towers stood outside again 70 to 80 feet high. A dipole type transmitting antenna was connected between the towers. The cable from transmitting tubes was connected at the center of the antenna wire.
Though I have very faint recollections of what I saw at Daund and Dighi, both these visits made a profound impact on me and were one of the reasons why I chose Electronics as a career. However, I realized much later that these two places must have been very important links in communication network of the British Empire in those years and had continued to be the most critical places through which first British India and then independent India, communicated with the world. Their dominance came to an end only when satellite communication dish antenna came up at Arvi near Narayangaon on Pune-Nashik Road sometime in late 1960’s.
After the visits, I had many questions in my mind. Though I
could find answers to most of these only after I trained myself as an
electrical communication engineer. After that my respect for engineers like
Marconi of early twentieth century, increased manyfold. With limited knowledge
and resources, they had created wonders without any doubt. Luckily now, a lot of material about beam
wireless concepts and stations such as Daund and Dighi has become available on
the net. It is therefore certainly worthwhile to go through history of these
places.
The idea of sending morse code signals by radio waves is not
new. Yet all the efforts to send these signals over long ranges proved
unreliable with many problems such as fading being faced. Only around 1920,
Scientists had realized the possibility of sending such signals by using short
wave carrier frequencies. By 1930 the
famous scientist Guglielmo Marconi had built and was offering a point-to-point
shortwave radiotelegraphy system for commercial use. Marconi also developed the concept of the
Beam Wireless system. In this, radio
frequency energy at shortwaves was concentrated into a narrow path, using a
complex system of antenna arrays. The first Beam transmitter in the world was
built at Bodmin, Moor, Cornwall, England, and the first beam receiver at
Bridgewater, Somerset, England.
The British Government of that time immediately realized the
tremendous advantage of Marconi system as it would now be possible for them to
connect to all the dominions of the empire on 24 X 7 basis. First to come up
were links to American continent. The first beam stations on the American land
were at Drummondville and Yamachiohe, Canada, being replicas of the English
facilities. Soon links were also established to Australia and South Africa.
The fourth Beam Wireless Station was constructed in India, with the transmitter station located at Dighi near Pune (Poona of those days), and the receiver station some distance away at Daund. The link stations in England for communicating to these facilities were set up at Grimsby & Winthorpe. The Marconi Beam Wireless Station in India was officially opened by Lord Irwin, and the first message from India to England was a greeting of loyalty to His Majesty King George 5. There were two transmitters at this station, both rated at 10 kW, and they were on the air under the call signs VWY & VWZ. This is interesting because concept of linking together a transmitting station using a particular carrier frequency and its call sign are used even today.
One of the questions many people ask is about setting up two separate stations for transmitting and receiving that are physically apart from as much as 30 to 40 Km. There is a simple explanation. Both these stations used different carrier frequencies and interference of transmitting signal in received signal was quite possible as effective filtering was not available in those days. To avoid this both these stations were set up physically apart. Interestingly these two frequencies, known as Uplink and Downlink frequencies, are used even today in all communication systems. For example, my mobile phone uses frequencies such as 2136.5 Mhz for Downlink and1946.5 Mhz for Uplink. We must appreciate the simple solution used by Marconi in those days to keep interference down at minimum possible levels.
We can also have an idea of the equipment that was used at
Dighi and Daund stations in those days. At
Daund, the receivers were probably Marconi Type R.C.25 Short Wave Receivers and
the antennas most probably of Rhombic type.
At Dighi, most probably Marconi High Frequency telegraphy/telephony
Transmitter Type SWB8E, or its earlier version, was in use. The antenna must have been a dipole array.
In World War II years, there were rapid developments in
radio communication engineering. In
addition to carrier telegraphy that was in use since 1927, Dighi and Daund stations
were upgraded and received new equipment for Carrier frequency based duplex
radio telephony and it became possible to route telephone calls from all over
India to the world from them. These two stations sent out and received radiograms,
cable-gams and photo-telegrams and linked up India with the United Kingdom, the
United States of America, China, Australia, Japan, Indonesia and Thailand. They
also maintained an internal service between Mumbai and New Delhi. The Central
Office at Mumbai served as a transit link.
The specific types of transmitters in use in the 1950s must
have been advanced for their time, utilizing vacuum tube technology for
amplitude modulation (AM) radiotelephony and radioteletype networks, far
evolved from the original spark-gap technology.
In the 1950s, the primary shortwave (SW) receivers were vacuum tube-based models. RCA AR 88 was a very popular receiver, and I might have seen these at Daund. Some old equipment was probably still in use, but since no official record exists, it is difficult to say anything. I feel that what I saw at Daund and Dighi must have been this newer equipment.
Both Dighi and Daund stations lost their relevance and importance when satellite communication dish antenna came up at Arvi near Narayangaon on Pune-Nashik Road sometime in late 1960’s. The antenna was linked to the Intelsat satellite. Since very effective filtering techniques had been developed by now, there was no interference of uplink signal on downlink signals and no need to have transmitters and receivers located with large physical distance like Dighi and Daund. International communications were also delinked from Posts and Telegraphs Department and a separate company known as Videsh Sanchar Nigam was incorporated and handed over this charge. This company was later sold to TATA group and privatized.
Even Arvi station, also part of TATA company, slowly lost
its importance as India started launching its own satellites and new dish
antennas came up at Bengaluru and Ahmadabad. Arvi dish probably is still functional,
but I could not find any information about its present role.
With these new developments, Pune lost all its importance as
a crucial linking station between India and the world. The land around Dighi
station now probably belongs to a private company, TATA Communications. About
Daund station, no trace remains. All
that remains now are the memories of these stations as no Government or private
authority ever thought of setting up a small museum that could house the old
equipment and display charts to
indicate how they functioned.
10 November 2025
