1985 report by Winston Nickols of re enactment 2022

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On a winters day in 1985, listeners to AM radio in the Hobart area around midday may have been
puzzled by an unusual racket for a 10 minute period. This was due to a re-enactment of a special
wireless transmission from Blinking Billy Point to a vessel in the river. Dave Thorne, VK7MR,
manager of the Radio Branch in Hobart had refurbished a spark transmitter, and after special
permission was granted by the Department of Communication Head Office and the International
Telecommunications Union, he sent three Morse messages from VK7XFM, while an interested crowd
of Radio Amateurs watched on. The messages were received by Len Edwards VK7LE, near
Lindisfarne on his vessel Marie Frances; Len would then forward them to recipients in Wales, U K,
the site of the very first wireless transmissions from shore to ship. One was from the Rotary Club of
Sandy Bay to the Rotary Club of Cardiff. This re-enactment was part of the Tasmanian Amateur
Radio Convention, TARC of 1985.

In July 1901, a Royal squadron of three vessels sailed into the Derwent River and Hobart. The Duke
and Duchess of Cornwall and York, later to be King George V and Queen Mary, were visiting
Tasmania. Hearing of the planned visit, local electricians and telegraphists put together the latest
apparatus that could transmit messages by spark wireless and waited. Excitement built as guns fired
from the Queens Battery, indicating the Royal Yacht was visible crossing Storm Bay. An 80 foot pole
supported equipment and an aerial wire on One Tree Point, (Blinking Billy Point), Sandy Bay and a
signal from XFM was broadcast. The commander of HMS St.George, some 8Km down the river
responded. The message read...' Tasmania sends a message of welcome to the Royal Yacht Ophir and
her escort'. A wireless conversation continued until the vessels tied up. The other support vessel
was HMS Juno.

One of the main instigators of this important event was Frederick William 'Pop' Medhurst, a
prominent Hobart experimenter and later electrical company proprietor. As no regulatory system
was in place, 'Pop' gave himself the call-sign XFM. This was only five years after Guglielmo Marconi
had demonstrated for the first time, a wireless transmission from shore to a ship.

The spark transmitter used for the commemoration was a replica of an early design and used a
35 Kilovolt supply voltage, keyed across a short gap. The centre frequency was 1850 Khz and the
raucous signal would have been heard across much of the AM broadcast band. Midday was chosen
as the time of least distant propagation, hopefully to cause less interference to other services. The
signal was heard well in places around the city and on Bruny Island.

During construction and testing, Dave had had problems with sparks flashing across the base board
and metal screws and even an old brass nameplate on the equipment glowed as he was attempting
to perfect the transmitter. He found the smaller the gap, the more power was radiated.

At Blinking Billy point, on-lookers gathered as Barry Riseley opened the demonstration. Dave had his
transmitter set on a table near his car and a wire aerial was strung up into some trees. He had run an
earth wire down into the water. Everyone present was warned the radiation may cause harm and
urged not to take sensitive electronic equipment near the site. Messages of greeting were sent and
Len Edwards on the far side of the river received these messages from the Lord Mayor and the city
of Hobart and read them back. They would be then be despatched to the U K, commemorating that
historic early wireless broadcast. Later a plaque was unveiled to mark the event. This was on the 8th
of June, 1985. A special day in the history of Radio.




                                                Wasten Nickols                   Nov 72072