Wireless Set No. 52 Canadian - Project

[David Dunlop]

I have been running the Remote Receiver each evening for a week now, between 30 minutes and an hour each time.

The valve readings from the meter have stayed very close to those initially recorded when I first fired the receiver up. The background noise seems to have dropped off a bit on the loudspeaker when listening to the WWV Time Signal and this is still all with the RF Gain at 'maximum' and the AF Gain at very close to maximum. The crystal calibrator pips are still somewhat buried in the background noise.

I decided to add another test to the mix on the weekend by checking out my Receivers, Headgear, MC, Mk.1 in both PHONES sockets. I figured this would tell me what both sockets were up to, that the Receivers Headgear worked and that the toggle switch between the loudspeaker and the headgear also functioned properly. Pleased to report all items responded correctly, but one point did surface I am curious about.

This is the first ever wartime wireless set I have ever worked on/listened to that is equipped with an installed loudspeaker. What I noticed straight away was the level of background noise seemed much greater via the loudspeaker circuit than the headgear circuit. I had to back off the RF Gain nearly 1/4 from full maximum and the AF Gain by about 20 % from where these two controls were set for the loudspeaker, when I was listening to the set via the headgear. I also noticed that through the headgear, the crystal calibrator signal was very clear at all three positions compared to when listening with the loudspeaker. The speaker is identified as:

LOUDSPEAKERS, 3-in, PM, 3.5 Ohms

Now it is still quite possible that some of the valves are not fully up to standard and this may be influencing the level of background noise I am experiencing, but can anyone advise if, in general, it would be expected for a wartime era loudspeaker in a wireless set to have a noisier output than a set of headgear?

David