Tube Radio Australia

ARB Restoration Project

I first spotted an ARB setup at a Radio Field day. Ray Robinson from Sydney Australia had his ARB setup with the DU-1 loop and I was impressed with its operation. It was there and then I decided I needed to get one.

After hunting around online and in the auctions I found two very sad ARB units. Both had been (Improved), where somebody had hacked them up, removing there plugs and antenna posts, one even had a mains power supply and holes drilled in the case for a speaker. Shortly after I found a DU-1.

The hunt was then on to find plugs and components to fix the units up. A year had gone by and my ARB projects was sitting on the shelf as many do when you can find the bits to finish them. By chance I came across another few ARB units and before I knew it they had started to multiply, three, four, six, and eight. Then one night the DU-1 stared to do the same, before I knew it I had three of them. The time had come to build up a few units. I hunted around and found plugs from Fair Radio and a few other bits from online auctions. I had enough to build an original setup with a pilot’s control box; I also will be posting the Navigators box on another unit shortly and the information and install of the Navy ZB-3 homing adapter.

This Consists of CW-69076 homing adapter w/mounting plate and cloth cover, CW-23214 pilot's control box w/mounting plate, CW-29173 switching relay w/mounting plate, antenna N.A.F. 48134-1 antenna, and spares box with complete contents. Also includes the scarce PLASTIC “Confidential” homing device card. .! Lots of Fun.

Anyway after a few issues with not supplying enough power to the unit I managed to get the first one running. A dead output transformer and Dyno Motor needed repair and then an alignment. Away we went. After playing around for a few hours I was DF locating LF beckons all over the place. Wow really cool on Long wave.

The Front View before Restoration. The Front After a cleanup Control Cable in place

Inside top view Dead Transformer

Making the Loop Cable Making the Loop Cable

Pilots Control Box Tuning Head and Drive cable

Close up of the Front Running Loop Amp on top of the ARB

Close up of the Loop Side Shot of the loop

ARB’S In Waiting ARB’S In Waiting

Navy ZB-3 homing adapter Components, Yes this sits on top of your ARB, he AN/ARR-2 is the combined version of the ARR-1 (also called the ZB-3)
and the BC-946 command set. Used for homing, mainly US Navy.

By Ray Robinson
Highly secret, they weren't declassified until 1949.

The ARR-1 was a small TRF set covering 234-258mhz, using acorn tubes, the output was 800-1000khz. This set then connected to the BC-946
which took the signal and demodulated it to recover a morse signal. The ARR-1 was also used with ARB and RU-18 receivers, there were 2 studs
on the top of these so it could piggy back, and be powered from the ARB accessories connector. Also powered from the power adaptor on the BC-946.

The ARR-2 was a combination of these, in a Command set sized box, which tuned fixed channels, and used minature valves in the font end.

An aircraft carrier had a rotating aerial, which sent out a different morse character depending on the direction. When you received that character,
the aircraft knew which direction to turn to locate the carrier.

To prevent the enemy using this system to loacte the carrier, several ideas were used. The range was small, only a hundred miles at 50,00 feet.
The codes were changed daily, so the pilot neede a new code sheet every mission. The frequency was high, the enemy had few receivers capable of tuning
this frequency. The transmitter was only on when aircraft were returning. The signal was double modulated, so if you had a single conversion receiver,
the output signal would be 1mhz, with modulation on that. Difficult for an audio stage to amplify, and to hear. The dial was engraved with the wrong frequency,