YG-11 DIVERSITY RECEIVER
The Canadian Army signals equipment policy meeting from 28 June 1944 has an interesting entry:
4.01 D. Sigs advised that approval has been obtained to purchase a Marconi Type YG-11 diversity receiver for use on the Ottawa terminal of the Canada – UK wireless circuit.
4.02 DECD (Director, Electrical & Communications Design) agreed to aid in processing spares requirements to ensure that the order could be placed concurrently with Navy and other orders on the manufacturer.
Could YG-11 be the model number for the triple diversity receiver comprised of three CSR-5Y’s and the Canadian Marconi type 105-930 common oscillator? We still don’t fully understand the Canadian Marconi system of assigning model numbers but is it possible that the CSR-5Y diversity receiver points to the YG-11 designator? From a few pieces of information , it was deduced that at least three YG-11 systems (perhaps more) were built. Looking for additioanl information. Contact: jerry.proc@sympatico.ca
Some points regarding diversity reception.
Space diversity was the most commonly used mode during World War II but it requires antennas to be placed several wavelengths apart to be most effective. Due to the amount of real estate required, operating at LF/MF frequencies becomes impractical. Therefore, starting the YG-11 coverage at 1.5 MHz makes sense. The Royal Canadian Navy publication BRCN 5422(2) states that an advantage of 10 to 15 db is usually obtained with space diversity reception as compared with single antenna operation
Frequency diversity is another option but the transmitting station needs to have two or three transmitters dedicated to a single radio circuit.
Polarization diversity - Multiple versions of a signal are transmitted and received via antennas with different polarization. It is not as effective as the two mentioned previously.
There are other diversity techniques listed in Wikipedia.
Contributors and Credits:1) Tom Brent [navyradiocom@gmail.com]
2) https://en.wikipedia.org/wiki/Diversity_scheme
Dec 12/2022