Malin Head Marconi Radio Station
Marconi Wireless Telegraph Station January 1902
The wireless room
was housed on the first floor of the square tower. Access to the
operations room was now from the ground floor.
In later years a new wireless operations building was constructed using
blocks similar to other buildings in the area and a flat concrete roof
and octagon in shape. The inside of the room was purpose built to hold
the wireless equipment.
This operations building was housed separate from the semaphore building
due to the noise and smoke from the spark transmitter when it was in
use. This may have been one of the reasons why it was moved as the
octagon was well ventilated and also had good visibility.
Each wall segment of the octagon had a 4 pane window with opening
section. One of the 8 sides housed the main door for access in and out
of the building.
The inside was furnished with wooden paneling and purpose built benches
to accommodate the shape of the building.
Carndonagh Amateur Radio Club QSL Card
The
Carndonagh Amateur Radio Club will be operating from Malin Head during the
International Marconi Day in April using the club call Sign EI0CAR.
During the Marconi Day every April by the Carndonagh Amateur Radio Club
where once again radio waves will be sent out worldwide from Malin Head.
Technical Info on the 1902 Equipment.
Malin Head Radio Station was established in January 1902 at the Lloyd’s of
London signal tower at Banba’s Crown. The stations radio was a simple battery
powered spark transmitter connected to a 120 foot aerial supplied by the Marconi
Radio Company. Operating through both World Wars, the station has witnessed many
historic events.
Transmitter
Simple Marconi Radiator. (Transmitter ) (Left Picture) =
B, battery; I, induction coil; K,
signaling key; S, spark gap; A, aerial wire; E, earth plate.
The left schematic of very simple battery operated spark gap transmitter may
have been used at Malin Head. A photograph of Marconi with a complete station on
the right of the picture there is a large induction coil with an open spark gap
which is directly connected to aerial and earth.
Receiver
His receiver used a coherer as its detector. Although
the coherer’s invention is often attributed to Marconi, it was actually invented
by a Frenchman, Edouard Branly, but it was Marconi who put it to great effect
and, as a result, became the world’s first DXer.
The coherer is a primitive form of radio signal detector used in the first radio receivers during the wireless telegraphy era at the beginning of the 20th century. Invented around 1890 by French scientist Édouard Branly, it consists of a tube or capsule containing two electrodes spaced a small distance apart, with metal filings in the space between them. When a radio frequency signal is applied to the device, the initial high resistance of the filings reduces, allowing an electric current to flow through it. The coherer was a key enabling technology for radio, and was the first device used to detect radio signals in practical spark gap transmitter wireless telegraphy. It became the basis for radio reception around 1900, and remained in widespread use for about ten years.
One electrode, A, of the coherer, (C, in the above
diagram) is connected to the antenna and the other electrode, B, to ground. A
series combination of a battery, B1, and a relay, R, is also attached to the two
electrodes. When the signal from a spark gap transmitter is received, the
filings tend to cling to each other, reducing the resistance of the coherer.
When the coherer conducts better,
battery B1 supplies enough current through the coherer to activate relay R,
which connects battery B2 to the telegraph sounder S, giving an audible click.
In some applications, a pair of headphones replaced the telegraph sounder, being
much more sensitive to weak signals, or a Morse recorder which recorded the dots
and dashes of the signal on paper tape.
The Antenna
The T- antenna was a 120 foot aerial supplied by the
Marconi Radio Company and appears to be sloping at 30 degrees from east to west
and secured above the ground behind the Banba’s Tower in the picture above. I’m
not sure where the feed point is at this time although this type of antenna can
be fed at any point. The guy wires connected to the top of the mast show signs
that they have insulators part way down.
Guglielmo Marconi
Click here to listen to a recording of Marconi's voice
By Peter Homer
EI4JR