Leitrim - Equipment INTERCEPT RECEIVERSAccording to The History of CBNRC, Chapter 12, Page 52, this was the situation with the receivers used in the Supplementary Radio System (circa 1971) as it was called back then.
"The aging receivers (half of them were over ten years old) comprised of 106 SP-600s, 14 Plesseys model ?, and 272 RACALs (145 of the old 17s, and 127 of the newer 117s but still using tubes rather than transistors . It was estimated by the CRTG that the intercept system required 286 basic receivers to stay in business and that the current equipment was badly in need of updating. A modified Eddystone EC 958 was accepted in June as the new standard receiver, and it was decided to buy 126 of them over a four year period to replace most of the RA-17s, and then see what to do about the 117s.
The situation with the antennas, especially for. D/F, was no better. Although there were new CDAA arrays at Gander and Masset, integrated for D/F purposes with the USN BULLSEYE system, the GRD-6s at Leitrim and Alert, and especially the GRD-501 at Inuvik, were old and insensitive in the lower band. There were also new equipment to be looked into. It was decided to purchase the Collins 651-S receiver, which succeeded the Collins 51S mentioned in a previous portion of the report (paragraph 12.40), but which had the extra advantage that it could be controlled remotely by a general purpose computer".
CLICK ON IMAGE TO ENLARGE
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Eddystone 956-3 . 10 KHZ to 30 MHz. CW, MCW, AM (DSB), SSA (A3A). See note 2 ( E-bay image) |
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Racal RA17. 0.5 to 30 MHz. (Image courtesy Allan's Virtual Radio Museum) |
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Racaal RA -117. 1 to 30 MHz. (Image source unknown) |
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Hammarlund SP600. Frequency range 0.5 to 54 MHz (Image courtesy Kurrarjong Radio Museum) |
| Plessey model unknown | Plessey receiver. Model nt known but there were 14 of them in the system around 1971. |
DIRECTION FINDING
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| AN/GRD-6 Adcock array which is comprised of 8 monopole antennas. (USN image) |
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| AN/GRD-6 operator's console . By April 1972, the GRD-6 DF systen at Lietrim was dismantled. (USN photo.) |
FOOTNOTES:1) CBNRC= Communications Branch National Research Council
2) Per the publication "Ultimate Eddystone Quick Reference Guide", page 45, it indicates that the EC958-3 was the variant built to the specifications of the Canadian government. The basic model during the 1969-73 time frame employed 41 transistors; 46 diodes and 12 ICs.The same manual defines the 958-4 as a 958 base model built for military or marine usage. It is believed that the 958-3 is the correct one for service in the Supplementary Radio System. The Eddystone operatotr's manual further define the model as 958-3 CAN.
CONTRIBUTORS AND REFERENCES:1) Bill Robinson <billrobinsoncanada@gmail.com>
2) Gerry O'hara <gerrycohara@gmail.com>
Feb32/25