Double Diversity Telegraph Receiver SPECIFICATIONS
Type: Double conversion superheterodyne
Circa: 1934 - 1954
Frequency Range:
| BAND | WAVELENGTH (Meters) | FREQUENCY (MHz) |
| # 1 | 13-19 | 24 to 16 |
| # 2 | 19 - 30 | 19 to 10 |
| #3 | 30-50 | 10 to 6 |
| #4 | 50 - 80 | 10 to 3.8 |
| #5 (New York only) | 80 - 100 | 3.75 to 3 |
STAGES:4 x RF amp
1st Detector
1st Heterodyne
6 x stages of 1st IF (250 KHz)
2nd detector
4 x stages of 2nd IF (70 KHz)
3rd detector.
Documentation: An Operators Manual is provided here. (Courtesy Tom Brent)Comments
Since some of the schematics are notated COTC Yamachiche (Quebec) , it is believed that these receivers might have been used in the Trans-Atlantic Beam system set up by COTC at their Drummondville and Yamachiche, Quebec sites. COTC means Canadian Overseas Telecommunications Corporation.
There are likely no Diversity receiver survivors today. It is believed that COTC was the only customer for the diversity receiver therefore no ‘commercial’ model number was ever assigned.The fact that there are drawings from a 20 year period in the same file that suggests it underwent regular upgrades.
COTC didn’t come into existence until 1950, when it was created as a Cown Corporation to take over the Canadian Marconi facilities that had been devoted to overseas communications since the 1920’s. This included the Drummondville transmitter site and the Yamachiche receiving station. Canadian Marconi also used Yamachiche for design, research and manufacturing and that, at least, partly explains the existence of diversity receiver revision documents.
On the west coast, COTC had a receiving site at Ladner (south of Vancouver) and a transmitter site in Langley. The 50kw transmitter site was dismantled in the 1970’s when COTC switched to a satellite link for Australia and New Zealand. The Langley acreage subsequently became home to the DOT west coast monitoring station.
Contributors and Credits:1) Tom Brent
2) Dave Whiting VA3QG
Mar 31/23