John Alexander Berry

Tuning in Ross Solly's Breakfast Show on ABC 666 Canberra on the AWA 525-M radio. ''Canberra Breakfast'' with Ross Solly can be heard on 666 AM from 6am to 9am weekdays

The official callsign for ABC Canberra is ''2CN'' and Radio National Canberra is ''2CY''.

The radio's AGC (Automatic Gain Control) circuitry in this demonstration is working extremely well. A negative voltage is produced in one of the two diode sections of the 6SQ7GT valve, and this negative voltage forms part of the ''feedback loop'' to control the gain of the receiver (depending on the tuning).

It should be noted that this receiver does NOT employ a separate RF amplifier stage, and as a consequence, the sensitivity on reception is only in the vicinity of 10 to 50 μV. As a comparison, a well designed communications receiver of that era had a much improved sensitivity of around 1 to 5 μV. (microvolts) due to the addition of a separate Radio Frequency Amplifier stage.

If you're located a long distance from the transmitter(s), the poor sensitivity of this receiver will result in ''background noise'' when you attempt to tune in the station....or...you may not even be able to hear the station !