The search for Mawson s wireless sets by John Gillies
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The Search for Mawson’s
) T RT=)G ee
y search began in February,
M2004, at the launch of the
Mawson station Jubilee stamps,
at the Post Master Gallery, in
Melbourne, on the 50th anniversary of
the founding of Mawson.
In the gallery, was the wonderful
model of Mawson's Hut, (erected at Cape
Denison, Commonwealth Bay in 1911),
made by Rod Mackenzie (Repstat 68).
Rod had received the plans of the hut,
as a gift from his daughter Jenny {Q92,
D95) and made the 1/12th scale model
from Baltic Pine.
In the corner of the workshop was a
scale model of the wireless which
attracted my attention. I asked several
museum people at the function if they
knew what had happened to the wireless Walter Hannam at Commonwealth Bay. — Photo by Frank Hurley.
sets. No one knew. hut, into an area where the bunks of On my trip on the Mariana Svetaeva
Douglas Mawson’s ‘The Home Of Dyce-Murphy, Whetter and Hannam in 2005, 1 renewed my interest in the
The Blizzard' gave descriptions of the had been removed by Hodgeman. These fate of the wireless. On the voyage I read
installation of one of the sets at bunks are missing in the hut at the a book, ‘Polar Castaways’ by Richard
Macquarie Island (Q), (call sign MOQI) moment. This area is adjacent to where McElrea and David L. Harrowfield,
and the subsequent attempts to erect an the equipment was installed in the which mentions that the SY Aurora had
antenna and communicate, while at south-east corner of the workshop. a wireless fitted following a collection
Cape Denison in 1912. The north-east area of the main hut being taken up in Sydney after a news-
Mention is made in the book of the has been partly excavated and I could paper appeal ‘by the Sydney Morning
erection of a new antenna by the crew of see that there were no bunks there, dur- Herald and the Sydney Daily Telegraph
the Awrora while they were waiting for ing my visit in 2005. At that time, [ had on 3 December, 1914. This was a
Mawson to return in 1913. On February not been aware that the wireless had Telefunken set as confirmed by John
8 after Mawson returned, the ship been shifted into the main hut, so | did Hooke, son of Lionel Hooke the radio
heard the station calling them back. not pay a lot of attention to that area. By operator on the Aurora (call sign WVSQ).
Macquarie Island was heard on Feb. 18 the size and weight of the transmitter However, the only contact was with the
and two-way contact made on Feb. 20 and receiver, they would have needed to New Zealand (N.Z.) station at Awarua
briefly and for an extended period on the be fixed to a table or bench. (VLB), to ask for assistance, when the
22nd. There is more mention of the
news from the outside world, the prob-
lem with maintaining the antennas and
the breakdown of Sydney Jeffreys.
The appendix of ‘The Home of the
Blizzard’ has an entry, Two complete
sets of Telefunken wireless apparatus
were purchased from The Australasian
Wireless Company (AWC). The motors
and dynamos were got from Buzzacott,
Sydney and the masts were built by
Saxton and Binns, Sydney. Manila and
tarred-hemp ropes were supplied on
generous terms by Melbourne firms
(chiefly Kinnear).’
‘Mawson’s Antarctic Diaries’ edited
by Fred and Eleanor Jacka, have a few
more details which I had not known
about., viz:
1 March, ‘Hodgeman gets space in
main hut for wireless gear.’
9 - 15 March, Wireless brought into
main hut.’
The famous photo by Frank Hurley,
of Walter Hannam sitting at the wireless
set in the corner of the workshop hut,
shows most of the equipment. Most of 4
this was evidently moved into the main Wireless Hill station Macquarie Island. — Photo by Arthur Sawyer.
Page 22 - Aurora - December 2008
Aurora had drifted out of the pack ice A letter to Mawson from AWA, 27 The type of crystals available for the
and had limped almost back to New March, 1911, said that wireless would receivers Mawson bought, is not listed
Zealand, as reported by Kelly Tyler- not work over that distance. Another let- anywhere but in the stocktaking list pre-
Lewis in her book, ‘The Lost Men’. ter from AWA, 29 March, stated that, for pared by Charles Sandell (wireless oper-
I communicated with Stephen a wireless to work over that distance, it ator and mechanic), when handing over
Haddelsey, author, of ‘Born Adventurer would cost 20,000 pounds and that the wireless equipment to the Bureau of
Frank Bickerton' and he wrote, “I can small ‘sledge’ wireless sets were not Meteorology, a ‘detector potentiometer
say with a lot of confidence, that the available. type HB14 No. 3083’ is listed. This indi-
Telefunken set used on the Imperial Mr. Hugh Denison was one of the cated that a carborundum detector, was
Trans-Antarctic Expedition was the original donors of one thousand pounds at least one type used. In the Telefunken
same as that used on, the Australasian to the expedition. He was the General catalogue it says that, ‘Carborundum
Antarctic Expedition (AAE).” Manager of the Australasian Wireless detectors had good sensitiveness (sensi-
What happened to the set after that? Company (AWC) and this company was tivity) with additional battery, great
Some reading suggests it was removed the agent for Telefunken wireless equip- overloads permissible and cannot get
and cleaned, while the Aurora was being ment in Australia. out of order (mechanical alignment)
repaired in New Zealand. At that time In a letter to the expedition secre- through vibration.” The catalogue also
there was the ruction about J.K. Davis tary, 13 Feb., 1912, Mr. Denison wrote lists potentiometers for carborundum
taking command of the Aurora instead of that the sets were sold for 650 pounds detectors. However, the only catalogue
Stenhouse. When Stenhouse was each and AWC had offered to buy them {ffrom 1917) in the Berlin Museum
sacked, Lionel Hooke was put off as back, for half price, when they returned. archives, does not have any numbers
well. However, I could find no reference AWC was merged with AWA in 1913, that match the numbers in the stock-
to the wireless in Stenhouse’s papers for which complicated the search. taking list from Macquarie Island.
this period. The only person to continue In February, 1912, no wireless con- In the photo of Hannam, on the pre-
on the Aurora was Aubrey Ninnis. tact had been heard from the expedition vious page, the panel in front of the
J.K. Davis wrote to his father, that and the newspaper that had paid for the receiver switch beside him, looks like it
they had a new, more powerful, 2.5 kilo- exclusive news, was becoming agitated has at least two adjustable potentiome-
watt wireless set, from somewhere in at the lack of information. This rattled ters. The photograph, taken by Sawyer
N..Z.. Davis had not been on the Aurora, the expedition secretary, Conrad Eitel, on Macquarie Island, on page 22, shows
when there was a wireless transmitter who set out to acquire some new wire- the equipment in a slightly different lay-
on board. There was only a receiver, on less gear and send it to Macquarie out, without the panel in front of
the relief voyages he commanded in Island. He sent letters to AWC saying Hannam in the Hurley photo.
1912 and, as far as I can find out, later that their equipment was no good and I had asked Allan Moore (M63, 65),
in 1913, when Mawson was finally that there would be legal action against who wrote the series (published in
picked up and brought back to them.. Aurora over a number of issues), ‘SO
Australia. in February, 1914. Father Shaw offered a wireless plant, years of Australian Antarctic Radio’, if
While I was searching at the Scott for 2000 pounds, that had been he had any contacts, from when he had
Polar Research Institute in Cambridge, installed on King Island. Eitel went
England, I ran the legs off Naomi as far as paying a deposit for hiring L. Drablofe Telegravhic
Boneham. the Archives Assistant there, a ship to go to Macquarie Island.
reading through material from that era. Contact was eventually made
I tried to find some mention of the sale with Sydney when all the equipment
of the Aurora, when Shackleton had fin- was installed in the huts built on
ished with it in 1917, to an American Wireless Hill. First contact from
company. There may be some informa- Macquarie Island was with a ship
tion in the papers of the lawyer they on 13 February. When contact was
used in New Zealand. Unfortunately the made with Sydney, Eitel cancelled
Aurora disappeared near N.Z., on its way the legal action and the hire of the
to South America from Australia, in ship.
1917 and is thought to have hit a On 25 September, 1912,
German mine. Macquarie Island heard a singing
Trying to find more information spark (the characteristic note of the
about the wireless, I went to Adelaide Telefunken spark transmitters) call
several times and was helped by Mark sign MAL (Mawson in Adelie Land),
Pharaoh to look at the records held in which meant that the transmitting 1
the Mawson collection, at the South set was working at Cape Denison.
Australian Museum. There were a num- The wireless sets bought by
ber of interesting bits of correspondence Mawson were a spark gap transmit-
from Mawson, regarding the wireless. ter and crystal set receiver. The set
He wrote to various companies request- worked on a wavelength of 600
ing information and possible prices. In metres (about 466 kilohertz). These
an undated letter to Amalgamated sets were meant for medium-size Hbb. 4. Rormale Egifidftation.
Wireless Australasia {AWA), he mentions ships using Morse code. There were 1. Siderung fir Gleiditvom, 13 Shisbewiderdande fiix 20. Ereegertapayitit. ca
<4 Ums.,
an offer of a wireless by Jesuits, but was no electronic tubes (valves) in the 2. Sdhaltes fir Bleidfivom,
ety und Hodire
queny Generater,
24000 om,
. Erregecielbitiadutiion,
reluctant to take up the offer. set for any amplification. 3. Bolimeres-midalier, 5. Biderungen fire Wedhiel 2. Wntennengmprremener,
4 Boltmeter, 250 Ralt, ftrom, 3¢ Hmp., 20 Anp.
From previous research on AWA The Telefunken transmitter, 5. Wntaffer, . Saaltsr i Bedielimem, Futennenuariomaeter,
papers in the Mitchell Library in Sydney, used a type of spark gap called a 6. Touventeguioter,
7. Glagftrommoter, 4 PS5,
. Bmperemueter
NyWedgiel:
frram, 50 Amp.,
28 Aniennenvertivsungd
Tapasitds,
while looking for information on the Quenched Spark Gap. It was a great 110 Bolt, 1500 Lumren, . Tafe, . Empiangdappazat,
repurchase of the wireless equipment, [ §—10. Hodirequenyfideran. . etadedrafiel 8. Primiee Trongfjormator:
success owing to the very high rate gen, Traudiovmator, 224,8600 foule de8 @uipiéngers,
had read that a Father Shaw in Sydney, of switching. This gave a tone to the 11, Podfrequensgeneraior, Bolt, 1. Teleghon.
2 KW, 330 8., 590 Bex., . L@iuntentrede, §-teotity,
was manufacturing wireless sets and transmitted signal, which made it
was in dispute with AWA for patent easier to distinguish from the back- Copy of page from ‘The German Radio Systems
infringements by copying Marconi ground noise in the early crystal set until 1945’ book, courtesy Telefunken Museum,
equipment. receivers. Ulm, Germany.
Anraora - December 2008 - Page 23
German, so | asked him to scan the
pages of the section relating to the 1911
equipment. (See picture on the previous
page.)
When I contacted Herr Hoppe, at the
German Museum of Technology in
Berlin, he advised that they did have
some equipment of that era that was
being restored.
As | had planned a trip to Europe
later in the year, I rearranged our trav-
el plans, to spend a day in Berlin. [ was
fortunate to find a receiver unit that had
just been restored, still in the conserva-
tor’s workshop and was able to examine
it closely and take many photographs. It
was a later version of the same unit, but
it gave me an idea of the sizes of the
unit. Herr Hoppe said that they had
some of the transmitter parts stored at
another site, so I was not able to see
them. However, I was able to look Antenne fErr T
Copy of Telefunken Catalogue picture of through the archives of the Telefunken
Model E4 very similar to the photo of the papers and old catalogues to see equip-
Macquarie Island equipment. ment that matched the Hurley/Sawyer
photos. The earliest that the papers
Model 5FE receiver that has just been
went back to, was 1917; some of the pic-
’rrmxsmi\fing set for restored in Berlin.
medium sized and
tures were very similar and had circuits
— Photo by John Gillies
large ovean lfiners that I was able to understand.
and for tand statfoms. /
Sevies spark gap of When [ saw the receiver unit, 1 was
sight sectiomy for surprised at the complex rotary knife
regalation of energy. /
Theee fixed waves
switching mechanism, that is not visible
between 300 and &30 in the AAE photos and the aerial
meters. / The trans- changeover switch that was operated by
mitting set inclades a lever, like the old one-armed-bandit
3 kVA - motor- gene
-
vator set amd aerial poker machines. Some of the contacts
taners. / For two that are operated by this handle, switch
o0 to 10 ft masts at the detector diodes out of the circuit
o distance of 120 to
240 ft the guaranterd
when the unit is in transmission mode
vange across the open and apply power to the transmitter unit.
iea iy 140 to 323
miles. / A suitable receiver is owr I can see how condensation in the
type ES {see seclion A, group V), cold workshop room, could easily have
built up a film of ice in these switches
Copy of section of Telefunken catalogue and not be noticed because they were at
with the English text for the type of the back of the unit. This could explain
transmitter unit as seen in the AAE pho- how contact with Macquarie Island was
tos. first made in late February, when the
room may have been above freezing for
worked in Germany, who might know of some time and later, when the set was
a Telefunken Museum. He suggested brought into the main hut where it was
writing to the Australian ambassador considerably warmer; it would also have
there, explaining my search. I received a prevented the build-up of ice on the
reply from Regine Pankuweit, Research switches.
Back view of restored Mode! SE receiver
Officer Economics/Technology at the
For some time while researching the unit in Berlin.
Australian Embassy in Berlin, with the
fate of the original wireless set, I had — Photo by John Gillies
Email addresses of two possible con-
been on the look out for suitable materi-
tacts in Germany. The first was a use to make the wireless set as similar
Telefunken Museum in the city of Ulm, al to use to build a replica of the spark
gap transmitter. The Leyden jar con- as possible. I analyvsed the photos I had
the other, the German Museum of taken and scaled the transmitter unit
densers (early capacitors) were a big
Technology in Berlin. When I contacted from the catalogue dimensions of the
problem. I had no idea of the size neces-
Fritz Arends at the Telefunken Museum Leyden jars and the dimensions of the
and explained what I was after (circuits sary, only a rough dimension scaled
from the photos. I had found plans of a receiver unit, I thought I would have a
and construction details of the 1911 go at constructing a replica for the
equipment), he replied that all the Quenched Spark Gap unit on the inter-
net. Centenary of the AAE in 2011.
paperwork had gone to the Museum in
Berlin. However, he found a photo of the When [ first saw the switching mech- Fortunately the ANARE Club
equipment in the German publication, anism on the receiver unit, I thought President, Brian Harvey, has a large col-
‘The German Radio Systems until that it would be too difficult to replicate lection of material in his factory, togeth-
1945 (3 volumes), describing the first it. However, after studying the photos I er with a large lathe that has enabled me
40 years of radio systems. He offered me had taken, to figure out how everything to get started on building a replica.
the set of books, but they were all in worked, I began looking for material to To be continued.
Page 24 - Aurora - December 2008
Building a Replica of the Wireless Set used by
Douglas Mawson’s 1911 Australasian Antarctic Expedition
— By John Gillies
previously downloaded, from the inter-
Continuation of article, ‘The Search
net, a description of how to make one.
for Mawson’s Wireless Sets’,
Brian Harvey (M77, Q79, C83), then
from Aurora, December, 2008.
ANARE Club president, had some large
sheets of copper. [ was able to cut them
In the article titled ‘The Search for into rough circular shapes, then bolt
Mawson’s Wireless Sets’, which I wrote them to a jig to hold them all together, so
for Aurora, December, 2008, (Pages 22 they could be turned in the lathe to
to 24), [ made some errors. On Page 22, make them round and all the same size,
I wrote that, by my observation during a for the heat sink fins. These dissipate
visit to the hut in December, 2005, the
the heat caused by the spark action.
bunks of Herbert Dyce-Murphy, Leslie Brian also had some large copper rod
Whetter and Walter Hannam were miss- that I turned to make the electrodes.
ing. These are enclosed inside large mica
In later years, excavation of the ice in washers, that the spark jumped
that area has exposed Dyce-Murphy’s between.
bunk, with the writing in the wall,
‘Wireless 1913’. There is still more exca-
vation to be done in that area, but there
were some electrical wires among the
ice.
I had wondered why no photographs
of the radio in that position existed.
There were other people on the
Australasian Antarctic Expedition (AAE)
with cameras, but the only photographs
Leyden jars, mounted in the transmitting
of the hut interior were taken by Frank
Hurley with the flash equipment he had. section frame.
When Hurley arrived, in 1913, the wire- mounted in a frame and clamped into
Copper electrodes for the spark gap section.
less equipment had been packed up for position, with the outsides of all the
return to Australia a month before tubes connected to the frame. The tubes
Aurora arrived to take them home, have wooden caps, with spring fingers
explaining the lack of other photographs that make contact with the brass sheet
of the wireless. inside the tube. They can then be con-
The bunk of Herbert Dyce-Murphy nected together to make different values
was just inside the door into the main of capacitance for the tuned circuit that
hut from the workshop. Douglas selects the frequency to be broadcast.
Mawson and Dyce-Murphy were the These actually work by storing the
only two people to have single level electrical charge as a stress in the glass.
bunks. The other part of the tuning circuit,
Just what parts of the wireless were seen in Hurley’s photograph and the
brought into the main hut, [ am not sure German Telefunken catalogue pictures,
of, at the moment. If the transmitter sec- is a spiral coil mounted on the frame of
tion was shifted there as well, there Spark gap unit assembled with large the transmitter unit. To make this look
would have been considerable rewiring heat sink fins. Mica washers can be seen realistic I had some 13 mm diameter
of the power system. between the electrodes. copper waterpipe, flattened by a panel-
As the aerial changeover switch is on
I had to have the washers made by
the receiver unit, there must have been
a manufacturer in Melbourne, Victoria.
quite a few wires through the wall into The ‘quenched spark gap’ unit is
the workshop. mounted in an insulating frame. The
Because the receiver did not need end sections are cut from a sheet of
any power to operate it, Sydney Jeffryes paper bakelite that Brian also had in his
could have listened on the headphones, workshop. There is a tension screw at
while lying on the bunk used by Leslie one end to keep the gaps inside the mica
Whetter in 1912. washers airtight to reduce oxidisation of
the electrodes.
BUILDING THE REPLICA WIRELESS
Leyden jars and transmitter coils
I have written an article about build- The Leyden jars, an early form of
ing the replica for the Historical Radio capacitors, took a few iterations. Firstly
Society of Australia. It is being pub- glass coffee jars, which cracked in the
lished in their journal, Radio Waves, cold weather. Then to large glass tubes
over several issues. This account is a which have thin brass sheets fixed
shorter, less technical version, and not inside and around the outside before
all in chronological order. being inserted into 100 mm brass tubes,
to make them more robust. The tubes
The Beginning had a circular ‘finger contact’ at the
The first item I started work on was base to make contact with the outside Copper pipe being flattened in
the ‘quenched spark gap’ unit. I had brass sheet. The four Leyden jars were panelbeater’s rolling machine.
Page 14 - Aurora - June 2012
beater’s rolling machine, until it was manipulated into all the matching
about 2.5 mm thick. It was then grooves. When the former sides were
annealed to make it soft enough to be fixed together, all the temporary holding
wound into a tight spiral. bolts were removed.
Initially I made the temporary coil From the circuits I had found in the
formers out of medium density fibre- German Telefunken catalogues, I was
board (MDF), but they were not solid
enough when grooves were routed into
them, to hold the copper pipe in the spi-
ral shape. However this proved that the
idea would work. Brian Harvey had
some more paper bakelite sheet that I
was able to shape into six-arm formers
for this coil, and the coils for the vari-
ometer, part of the antennae matching
Three coils of the variometer unit.
Mawson’s Telefunken receiver unit
The Telefunken receiver unit was a
tuned primary, crystal set. The photo-
graph, taken by Hurley, of Walter
Hannam in front of the wireless set at
Commonwealth Bay, just shows the top
front of the receiver unit, with the cou-
pling coils visible. There is a panel
propped in front of and hiding the tun-
ing capacitor, which is shown in the fol-
Transmitter unit. lowing Telefunken catalogue picture of a
1911 model receiver.
I was puzzled for a long time as to
able to figure out how the transmitter what this panel was, but recently found
section was connected. The spark gap
some pictures on the internet of a mul-
was operated by a large voltage (8,000 tiple detector panel. This was a unit with
Y volts) applied to the unit, from a trans-
a number of different types of crystal
former that had 220 volts at 500 cycles
Jig to rout the grooves in the coil formers. per second (c.p.s.) applied to the pri-
mary winding of the transformer, when
I made a jig to hold the former the morse key was operated. This gener-
shapes on a sliding platform with the ated a spark with a tone of 500 c.p.s.
router fixed above it. A long screw which could be distinguished by the
advanced the platform holding the for- receiving station from the normal
mer 2 mm for one turn, as the former atmospheric electrical static and light-
was rotated 60 degrees, making grooves ning-generated noise received on
12 mm apart, in each arm of the face of Macquarie Island.
the former. The transformer in the replica was
The formers were bolted to another made to this shape by soldering a piece
sheet of wood and the copper strip of tinplate around two oval-shaped
wound from the tight inside diameter to empty herrings tins. The top was rein-
the larger outside. Each turn was held forced with a heavier piece of steel and
in place by a lot of bolts and washers the insulators fitted on top. These parts
until the other face of the former was were then mounted on a wooden block,
placed on top, and the copper strip with wires passing underneath, for the Telefunken catalogue picture of 1911
morse key to operate a relay under the model crystal set.
bench.
The variometer unit was made using
three spiral coils, made in the same way
as those for the tuning coil for the trans-
mitter. This unit is used to ‘impedance
match’ the transmitter to the aerial sys-
tem, so that the maximum power is
transmitted towards the receiving sta-
tion. It works by making the magnetic
fields of the coils interact, making the
total inductance appear larger or small-
er, depending on their connection and
position of the coils. Once they are posi-
tioned for the maximum power transfer,
they are locked in position by a large nut
Flattened copper strip held temporarily on the axis of the coils. Walter Hannam at the wireless in 1912.
in spiral coil shape. — Photo by Frank Hurley.
Aurora - June 2012 - Page 15
Replica rotary knife switch. Insulator and aerial changeover switch on the
Coil coupling rotator and tilting axle.
Berlin Museum unit.
detectors that could easily be switched rest of the unit. I could not find anything
into the circuit to see which type gave the 220-volt power to the morse key and
transformer, in the transmit mode, pre- like this, so I turned a large diameter
the best signal in the headphones. section of natural (white) Delrin to a
I was lucky enough to see a later venting power being applied to the
transmitter in the receive mode; and one similar shape.
model Telefunken crystal set being The aerial switch weighted arm was
restored in the conservator’s workshop bank removes the earth from the crystal
set in transmit mode, an extra safety milled from a square section of brass,
of the German Museumof Technology in after numerous trials were done with
Berlin, Germany, when I visited in 2008. feature. The arm that operates the aeri-
al changeover switch, also carries the wooden arms to get the shape correct to
I was able to examine it closely to see do the job.
how it operated and take many photo- aerial to the crystal set in the receive
mode. The pivot that is fixed to the insula-
graphs. When I returned home and tor, was milled from another piece of
examined the circuits I had photocopied I cut the rotary switch blades from
the copper sheet that was used for the brass and later nickel-plated.
from the museum archives, [ was able to [ was fortunate that one of my sons
determine eventually just what every- heatsinks. They had a square section
hole cut in the centre, which fitted along worked in a factory where [ was able to
thing did. use their drill/ mill machine and a small
The rotary knife switch, at the rear of a square section of paper bakelite, so
that they all rotated together. They were lathe for those parts.
the receiver unit is not visible in any
previous photographs and caused me separated by short sections of Delrin
tube. The pivot went though the centre The receiver coils
some trepidation as to whether I could The Telefunken crystal set was made
replicate it. of the square section piece of paper
bakelite, which insulated them all. The to cover a number of wavelength bands
On the same operating arm was a with different coils that could be inter-
lever that operated the aerial changeover angle of the operating handle took a bit
of trial and error until I was happy. The changed. The secondary coil could also
switch. It had a heavy arm which was be swung upwards to vary the coupling
used to make sure there was a good con- handle is attached by some small grub-
SCrews. between the coils. To change this coil, it
tact between the aerial and the trans- had to be swung up to clear the primary
mitter in the transmit mode. It took The fixed contacts of the switch were
fabricated, again with a lot of trials, coil in the centre, then rotated through
some figuring out, using the -circuit 90 degrees to enable it to be unplugged.
drawings and the photographs 1 had using bent pieces of brass strip, until I
had the dimensions right, to make a jig This mechanism took some figuring out
taken, how the chamgeover switch from the photographs I had taken in
worked. My replica arm is a mixture of to bend all the pieces of brass strip to
the same shape. I used brass shim, Berlin. It was eventually made with
the earlier 1911 model and the 1917 some plumbing pieces welded together.
model that was being restored in the nickel-plated before assembly, but the
original was probably silver-plated A retaining ring to prevent over-rotation,
Berlin Museum. which would break the wires to the set
The rotary knife switch has a num- phosphor bronze to maintain the con-
tact pressure. was made from a section of brass tub-
ber of banks: three banks switch the two ing.
crystals out of the circuit completely in The aerial changeover switch on the
the transmit mode, probably to prevent model being restored in Berlin, was
any damage to the crystals; two switch mounted on a large porcelain insulator,
with special fittings to hold it in posi-
tion, and hold the switch clear of the
Delrin insulator and aerial changeover
Rotary knife switch components. Mini Leyden jars for aerial matching circuit.
switch on replica wireless.
Page 16 - Aurora - June 2012
After a trial winding a coil with
enamelled copper wire proved a failure, I
was given a roll of fabric-covered Litz
wire, used on the original coils, by a
member of the Historical Radio Society
of Australia.
I had joined the society a few months
earlier and there met a fellow, Ian
Malcolm, with whom I had worked in the
postmaster-general’s department (PMG)
in 1968, between my years at Mawson
and Casey. lan had been a long-time
member of the society and introduced
me to [an Johnstone, an avid collector of
old radio equipment. He supplied the
Litz wire and some of the old-type large
meters that were used for measuring the
voltage current and radio frequency cur-
rent.
The aerial coupling capacitor
Seen on the wall under the variome-
ter, this is part of the aerial matching
circuit. It is made from several large
glass test tubes with metal inside and
shim brass around the outside, to make
‘mini’ Leyden jars.
Foundation, with the completed replica at a Mawson’s Huts seminar in
I was lent an original Telefunken
capacitor set by lan Johnstone, to meas- Hobart, Tasmania, April, 2011.
ure and copy. The original had shim tin — Photo by Anthea Wallhead.
on the outside which I could not find, so The lampshade There is also an oscillator that can
I used some shim brass. [ coated the A lampshade similar to the one in sound a 500-cycle tone over a loud-
brass with plumber’s solder, using a Hurley’s photograph was very hard to speaker, when the morse key is operat-
torch and wiping the solder over the sur- find. I eventually carved a wooden scal- ed. This is only for special occasions,
face, a small section at a time. This lop-shell shape, which [ used as a mould when the perspex panel is removed to
made a tin-looking surface. to make one out of fibreglass. When the allow access to the key.
fibreglass was removed from the wooden
Morse key pattern, the imperfections were filled The finale
The morse key was milled from some with automotive body filler and sanded I took the wireless to Hobart,
brass bar to match one in a picture of a smooth. The inside was spray-painted Tasmania, in April, 2011, for the
Telefunken key. white and the outside with a brass-look- Mawson’s Huts Foundation seminar,
Most radio operators had their own ing paint. where I assembled it in the Royal Society
favourite type of key, and usually took it The original lamp would have been Room, of the Tasmanian Museum and
with them. As this wireless set keyed the powered by the 110-volt DC (direct cur- Art Gallery (see photograph above).
220 volts at close to 10 amps, the con- rent) generator that was used to supply
tacts needed to be of large area. power to the field coil of the 220-volt 500 Because the proposed replica of
c.p.s. generator, and for lighting the Mawson’s Hut has not yet been built in
hut. Hobart, I decided to see if the Mawson
Centre in Adelaide, whose curator, Mark
Pharaoh, has been a great help in my
research, would be interested in having
the replica on display. He was only too
happy to do this, so I added some legs to
the bench. The original was fixed in the
corner of the workshop in Mawson’s
Hut, but the replica would need to be
free-standing. I bought some sheets of
perspex to fix across the front and side
of the bench as bracing, to make it more
secure.
In late January, 2012, I took it to the
Replica Telefunken morse key. Fibreglass lamp shade, with a globe Mawson Centre and, with the help of
which is missing in Hurley’s photograph. Mark Forecast (W65, M67, Q69), assem-
The bench and wall panel bled it in a space there.
The bench is made from one-inch- Transformer and oscillator It is on public display in the Centre,
thick tongue-and-groove pine boards, Under the bench is a box with a behind the Adelaide Museum in North
again supplied by Brian Harvey. The transformer to power the 12-volt globe Terrace. Opening hours are between
original was probably made with off- in the lamp. It also powers some elec- 10:00 a.m. and 4:00 p.m. weekdays.
cuts of the timber used to clad the build- tronics that replay a morse code mes-
ing. The wall panelling is made from sage, (MQI (Macquarie Island) station Note: All photographs are by the author
Baltic pine lining boards, of the same calling MAL (Mawson in Adelie Land) unless otherwise attributed.
profile as those used to line the hut at station), with some radio-type noise,
Commonwealth Bay. over the headphones.
Aurora - June 2012 - Page 17