Wireless Set Number 52

The Canadian WS52 Receiver was designed and built in Canada by Canadian Marconi to be used mobile or a ground station.

The mechanical design is excellent and contributes to its stability. It is possible to tune in an SSB station with no need for readjustment over long periods, unlike many of its contemporaries. Not bad for a set never intended for sideband working.

The frequency range is from 1.75 to 16MHz and it has a crystal calibrator which enables any frequency to be set up within 5KHz, fine for AM working.

The tuning dial is similar to that used in the 19 and 22 sets with a mechanical FLICK/SET/TUNE facility, as near as they got to a memory system. The three bands are colour coded:

Wireless Set 52 Bands
Band 1Green
Band 2Yellow
Band 3Orange

As an eight-year-old operator of this receiver, the same colours on the band change switch made tuning a doddle, especially as we had dumped the manual as so many of its professional users had years before.

Above the main tuning dial is a fine-tuning adjustment, spring-loaded to centre. A meter reads for both the Receiver and Transmitter and enables every valve in the set to be checked. Monitoring a valve under AGC control offers tuning indication, going for a minimum reading.

For CW use, the set really comes into its own. Unlike most others of its class, there is a good CW filter tuned to around 800Hz, it not only cuts out unwanted signals, but boosts the wanted one.

The circuit is fairly conventional for the period with one RF and two IF stages, the first two IF transformers are double tuned and the coupling is increased by putting the selectivity switch to FLAT.

There are 13 valves used in it - all 12 volt and mainly ARP3s.

The IF frequency is a non-standard 420KHz.

The main fault to which they seem to be prone is the common one of resistors going high or open circuit. It is worth checking them all, as the set is easy to work on. The same goes for the capacitors.

The sensitivity of the receiver is almost up to present day standards, being in the region of 0.7 microvolts for a 10 to 1 signal-to-noise ratio in CW and 2.5 in AM.

It is also protected by a gas discharge tube across the aerial input, something that scared this eight-year-old operator. His bother told him it was a bomb, set to detonate if I did not let him have his turn.