AWA Broadcast
Equipment

The owner of the unit told me that it capable of picking up speech up to 3 metres away.

This and another matching unit serial numbers 180 and 192 were the first microphones used at radio 3GL according to the late Jack Mathews who joined 3GL as a lad when the station opened.

I measured the marble block as; Width, 104 mm, height 101 mm, depth 76 mm.

Powerhouse Museum have another, serial no. 90, used at the opening of the Sydney Harbour Bridge.  :They also say that it is believed that AWA made less than 100 units.

Ref. Powerhouse Museum web site accessed 18 Aug 2008.   They have now been advised of the 2 Geelong units with the higher serial nos.

Above; AWA Reiss Microphone Top view
Left: top side view.

Kingsford Smith and Charles Ulm are shown talking into one of these just
after their historic first crossing of the Pacific by air.

The design of this unit originates from the early 1960s.
They use Germanium PNP transistors.

The top unit was installed in 3DB studio at the rear of the former Herald Sun Newspaper building in Flinders Lane, Melbourne.

I visited the studios in about 1966.
They were below street level.
Quality was taken seriously in that era.
They still seemed to have some rack mounted valve amplifiers in the control room.
The actual studios were of concrete boxes floating on cork as I recall.

The lower unit is on display at the Kurrajong Radio Museum, Blue Mountains.

This particular unit has been modified with
an enlarged meter and tone call.

Model G58250

Photo courtesy of Mat Robins

This unit dates from early to mid 1950's.
It has a valve regulated HT power supply.
The audio signal is generated using a wein bridge oscillator.
It uses a pair each of 6AU6 and 6AQ5 valves to produce the signal.
The valve sockets were punched out of the chasis for octal sockets but
minature 7 pin sockets were installed.

Unit courtesy 3YB, but had not been used for several decades.

This unit dates from early to mid 1950's;
lots of octal valves.

John, from former 3GL, allowed me to rescue it from dumpmaster bin.

This unit kindly made available by Mr L. Blasco

Valve technology.
The central knob sets the desired % modulation depth
at which the red light above it will flash.

At least three of these are used in Melbourne
at AM amateur radio stations on 1843kHz and 3.6 MHz.

The first one of these that I saw was at 3SR Shepparton in the summer 1968.   That transmitter site was built in 1956.  It was all AWA, even the antenna tuning box.

There is also one next to the AWA BTM-P5 at Mildura.

1975 design, 6 transistors and 2 I.C.s.
Requires about 50 milli watts of R.F. input.

This unit, made about 1970, was unloved, except by a mouse
who had done all it could inside including die.

This particular unit fed the 2.5 kW AWA BTM-2 transmitter above.

It uses a FET for gain control along with a transistor amplifier.
To revive this unit it took 2 evenings of cleaning,
lubrication and replacing some overheated resistors.

Used for checking audio line voltages.

Thanks to purchaser of site, Alf Brown
with lots & lots of help from Rodney.

AWA Gain Measuring Attenuator

It uses 2 Current Transformers and a voltage detector and
interfaces with a meter and direction switch (not yet)shown.

This apparatus was required for proof of power checks by the ABCB.