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Notes on some photos ex 7DX   Richard Rogers, VK7RO, September 2004

"Watty" Watkins, T336, 7AA, 7DX, OA7DX, VK7DX.
William Trevor Watkins was born on 27th March, 1898 and became the leading wireless experimenter in Hobart before his untimely death (from TB?) on 25th August, 1931.   Many of his papers were preserved [by his uncle/brother?] and passed to the Wireless Institute in Hobart.

0unknown
Written on back:
nil

My comment:
This is probably a Tasmanian shack as there are several 7 cards on the wall.

Of interest is the power supply on the lefthand wall.   This consists of several "hedgehog" transformers, two rectifying valves and several filter capacitors.
The late "Chas" VK7CH told me that hedgehog transformers were originally used in telephone work and that amateurs would connect several with their primaries in parallel and their secondaries in series to get high voltages for transmitters.   Hedgehog transformers were also sometimes used as filter chokes.
A hedgehog transformer in my collection is labelled 200 at one end and 300 at the other - these are the winding resistances.   The turns ratio is about 1:1.

2FP
Written on back:
The new [lamda=wavelengths] operative from April 1st as follows:-
133 - 50
75 - 85
41 - 42  \
20 - 21   | very narrow hi.
10 - 10.7 | ? hw are we all going to get in such a small span hi
5 - 5.3  /
This dope from Radio Insp OM so its OK
There will be a demand on QRM meters hi
Cherio 7DX from OA 2FP E.J.Baker 13-2-28

My comment:
VK2FP, E.J.Baker was in Newcastle in the 1933 callsign list.
I like the waistcoat and sleeve spring
Receiver on left   transmitter on right   centre???


3Mawman
Written on back:
On the left the ??? S.W. receiver   on the right the BCL set a 3 toob Reinartz.   The speaker is of the cone type a "Sferavox"   on the bench opposite the BC set is a key & buzzer for CW practice   the phones on the right of the buzzer are Brown H2 on the left a pair of Federal   the HT Batts are (2) 45 volt blocks Everready the supply plate juice for the SW set also the BC set   the clock on top of the batts is only a cheap thing price 2/- gains five minutes in 48 hrs   has been running for 8 month and not busted yet.   The type of valves used hr are UX199s and Mullard PM3 & 4s
G W Mawman 2nd op OA 3AB   "Premont"   Cheltenham Rd   Black Rock   S9 Vic.

My comment:
This appears to be Mr Mawman's home set up for listening only.   But apparently he also operated 3AB, which was owned by J.W.Leonard at Black Rock.
The moving iron loudspeaker on the right has what we would now think of as an inverted cone.


3LG
Written on back:
Les Shack   3LG

My comment:
VK3LG, L.G.Glew, was at Newport in the 1929 callsign list.
The clear panels on the equipment were probably made of glass.


3LP
Written on back:
A-3LP   Get the ole mike hanging on wall to left.   Gess wl tri fone wi u one nite om.
The long black slab behind the cans is the hi loss recr.   The arrangement to rite of modulation meter is the "famous" bug & hand key.

My comment:
VK3LP, L.A.Paul, was at North Fitzroy in the 1929 callsign list.
Note the ceramic knife switch between the transmitter and receiver for aerial changeover.   The transmitter appears to use pancake coils.
It's interesting that the receivers usually used a front panel, but the transmitters did not.


3ML
Written on back:
With best wishes from Bob Cunningham VK3ML 1.2.29

My comment:
VK3ML, R.H.Cunningham, was at Malvern in the 1929 callsign list.
Note the DANGEROUS sign.
The transmitter is an impressive rack and panel job.


5BD
Written on back:
Mr F.E.Earle OA5BD   Earle's shack

My comment:
He was at St Peters in the 1929 callsign list.
The receiver at top left uses plug in pancake coils on the front panel.
The transmitter on the right has jack plugs and sockets on the front - was this for bandswitching?


5BY
Written on back:
To Wattie 7DX   Best wishes and happy recollections of Ohms law
5BY does not believe in overloading and high power, hi!
QSU Doug 5BYacker

My comment:
VK5BY, D.R.Whitburn, was at Toorak Gardens in the 1929 callsign list.
QSU means send a reply.   This rig spreads over two tables.   The receiver has a front panel and the transmitter is open.


5DX
Written on back:
To 7DX de 5DX

My comment:
VK5DX, D.G Taylor, was at Forestville in the 1929 callsign list.
The power supply is under the bench and on the floor is what looks like 24  jars of a  chemical rectifier.   The log book for 7HR/7WI often mentions the maintenance requirements of their "slop-jar" rectifier.


5HG
Written on back:
73 OM & tks for kind visit

My comment:
VK5HG, H.M.Cooper, was at Glenelg in the 1929 callsign list.
OA5HG's transmitter.   The OA prefix means that this photo must be from about 1928.


5WH
Written on back:
nil

My comment:
VK5WH, W.H.Barber, was at Cumberland in the 1929 callsign list.
5WH has an impressive array of QSL cards.   Note the "DANGER DON'T TOUCH 4000 VOLTS" sign on the wall!


5YW
Written on back:
To 7DX 19/11/27
from R.W.Arnold 5YW 1WW ]skull and crossbones]

My comment:
VK5YW is not in the 1929 or 1933 callsign lists.
5YW has a glass panel for his low loss regenerative receiver and a danger high voltage sign on the wall.
Note the large QSL from PCJJ.


7DX_2
Written on back:
A-7DX - Taken July 11th 1926. Flashlite   Showing vy small xmitter tt was used in May-June T.P. [Trans Pacific] Tests   Colpitts ckt - Dutch tube Z2B (30 watts)   Receiver 10 - umpteen [lamda] metres   Small absorption portable wavemeter on right. (60 - 100 [lamda] in then hi!)   Xmttr was operated on 35 - 36 [lamda] using 5th harmonic of large aerial single wire.   Bug on left of rcvr.   Gear mostly homemade & constructed bar sockets condensers etc.   Owner op Trevor Watkins

My comment:
VK7DX, Trevor Watkins, was at Hobart in the 1929 callsign list.
The works of the transmitter and receiver used by 7DX for the Trans-Pacific tests in 1926.


7HL
Written on back:
nil

My comment
7HL H.F.Lovett was in Hobart.   Note the enclosed receiver and the pancake coils in the transmitter.


7NW
Written on back:
7 1/2 min   7.9

My comment:
Not in the 1929 or 1933 callsign lists.
The displayed QSL card A.7NW dates this to about 1927?


7PF
Written on back:
dunno - can't find photo


My comment:
7PF had an impressive setup in Launceston.   On the floor is a rotary converter for high voltage generation.   Note the large horizontally mounted valve in the bread-board transmitter.


A2CX
Written on back:
A.2CX   Complete station   Contains also A2WI

My comment:
VK2CX, A.W.Munro was at Bondi Beach in the 1933 callsign list.



A5DX
Written on back:
To radio A7DX with kind regards from Once radio A5DX   Don G Taylor

My comment:
Is this the receiver table with the transmitter shown in 5DX?


A5JA
Written on back:
To oa7DX de oa5JA   wid best 73's   13.5.27
Dx   oa, oz, bn, od, pi, ac, am, aj, nu, nc, oh, fo, fk, ef, eg, es Ireland
I think you can pick the various instruments ob so won't describe further.
It may be handy to know I took this snap with a 100watt lamp & aperture 7.7 on lens.   Hold ur lamp just above camera to avoid shadows.   Time 4 mins.


My comment:
VK5JA, P.J.Brewer, was at Parkside in the 1929 callsign list.
The enclosed transmitter and valve rectifier power supply under the bench still needs a "Danger do not touch" notice.


LadyLock
Written on back:
Receiving apparatus   SS Lady Lock   L Glew 5 1/2 x DC
2 cols Radio Talks

My comment:
The radio equipment on the Lady Lock (a lighthouse supply ship?)
7AA apparently wrote the Radio Talks column which appeared in the weekly Illustrated Tasmanian Mail


LambertWA
Written on back:
To Radio OA7DX.   73s fm F.C.Lambert.
[in pencil] W Aust (sent qsl card on my sigs)

My comment:
He is not in a 1929 callsign list, but appears as VK6FL at Geraldton in 1933.   Perhaps he was only a listener when he sent this photo.


OA5DX
Written on back:
Compliments to 7DX from OA5DX

My comment:
A later and higher power transmitter at OA5DX?


OA5HG
Written on back:
73 om & tks for kind visit

My comment:
VK5HG, H.M.Cooper is at Glenelg in the 1929 callsign list.
The same transmitter as shown in 5HG.


OA5HY
Written on back:
73 fm oa-5HY

My comment:
VK5HY, A.A.Cotton is at Kilkenny in the 1929 callsign list.
The neat station of OA5HY set up at an exhibition.   Note the microphone - all? the others pictured appeared to be CW only?


TrevorWatkins_7DX
Written on back:
dunno - I can't find the photo

My comment:
Trevor (Watty) Watkins 7DX at the key in 1926.   Flashlight?   Apparently taken at the same time as 7DX_2 (11/7/26).


VK3AX
Written on back:
VK3AX

My comment:
The VK prefix means this is 1929 or later.   He appears in a 1933 callsign list as H.D.Boast at Elsternwick.


VK3BQ
Written on back:
The new shack.   14 minute exposure by 60 c.p. [candle power] lamp.   hi!

My comment:
The station of Max Howden of Canterbury, one of the early exponents of crystal controlled transmitters.   Note the micrometer at right foreground.


VK3DC
Written on back:
VK3DC   Main transmitter   April 1929

My comment:
VK3DC, S.A.Embling is at Toorak in the 1933 callsign list.
A very impressive transmitting valve!


VK3RG
Written on back:
Gil Blake

My comment:
At Castlemaine in the 1933 callsign list.
What is the unit on the stool?   A wavemeter built in a billy?


VK3WI
Written on back:
D'you see the 7WI crd on the wall hi!
Hope qso 7WI soon & wish all gang @ ur end 73 fm all gang this end
Cedric Serle   VK3RX   Hon Sec Aero Club Section WIA Victoria

My comment:
The QSL card from VK3WI at Essendon airport.   


VK4PL
Written on back:
VK4PL

My comment:
He is not in the 1929 or 1933 lists.
Overall and details of the single valve rack and panel transmitter at VK4PL.


VK6MO_1
Written on back:
VK6MO   SW transmitter and charging switchboard partly seen on right.   High  & low tension batts below xmtr   (note kerosene case mounting)

My comment:
In 1929 callsign list - Magnetic Observatory, Watheroo.
Note the large number of batteries needed to operate a transmitter when there was no mains supply available.


VK6MO_2
Written on back:
VK6MO
Left to right and downwards.
Meters, frequency meter (absorption), time signal receiver 600M.
Monitor & heterodyne meter, message file & log, & batts for time signal receiver.
S.W. receiver.
On table key and transmitter plate milliameter.

My comment:
The receiving set up at VK6MO


VK6MO_3
Written on back:
VK6MO   Feb 1930
Left to right.   Xmtr, charging board, B.C. rcvr, 3' square baffle board speaker, gear as other photo

My comment:
An overall view?


VK7RY
Written on back:
dunno - can't find the photo

My comment:
Edgar Nicholls at Burnie used this set up for broadcasting on the medium wave band in the 1930s.