Wireless Set Type A MkII ("Ack" set)
The A set or "Ack" set from the late 1920s, covers the frequency
range 150 to 400 meters (2,000 to 750khz) and has one valve (AT26)
in the sender producing 25 watts. The receiver has 3 valves (AR3), which
function as a grid leak regenerative detector and two audio stages. The
modern phonetic code is Alpha, Bravo, Charlie, ...... but in the 1920s
it was Ack, Beer, Cork, ... and that is why the Wireless Set A is known
as ACK and the C set is known as the Cork set. I recently found some parts
in a shed clean out, and they are parts of an ACK set. I found the front
panel largely complete but missing a knob and 2 meters. In another box I
found the knob, and in another the aerial meter. The owner (NP) has had the
wooden case for the set in his home, since he was a boy, and gave it to me.
IB and PK have given me other parts including the valves, knobs, a chassis
and other parts. Thank you all. Missing from the sender is the morse key,
and voltmeter. I have 1 knob and some other parts which may be part of the
receiver. In the photo, the operator is using the morse key to send code.
Wireless Set 'A' MkII (183k)
Operator sending morse code on the A Sender(99k)
Close view of the A sender (41k)
Close view of the A receiver (73k)
A sender circuit including wavemeter(14k)
A receiver circuit(15k)