MARCONI CSR5 RECEIVER AND CM11 TRANSMITTER

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csr5.jpgCSR5 RECEIVER

First built by Canadian Marconi in 1942, the thirteen tube CSR5 general coverage superheterodyne receiver was capable of receiving CW or AM signals in the 80 khz to 30 Mhz bands. These receivers were used  to receive the fleet broadcast or guarding the International or marine distress frequencies. The most notable feature, is the four position, selectable, IF band pass filter which helped to reduce interference. The RCN also modified all of the CSR5 receivers. In order to receive the 73.6 KHz fleet broadcast frequency, the "F" band (80 to 200 KHz) was calibrated 10 kHz lower than the dial reading. This frequency is still assigned to Maritime Command today. 

cm11.jpgCM11 TRANSMITTER/RECEIVER

First built in 1942 by the Marconi company, the CM11 was a transmitter  and receiver capable of operating in the 375 KHz to 13.8 MHz bands with the exception of the broadcast band although LF was never sent from ships at sea. It was rated for 100 watts for CW, 70 watts on MCW or 30 watts on AM. Without a doubt, it was the workhorse of the radio office. The internal antenna tuner could match any antenna that was 5 to 750 ohms resistive between 515 KHz and 13.8 MHz. Unfortunately, at 478 pounds, the CM11 wasn't very portable, but if one had to, horseshoes could be forged on the cabinet, something that can't be done with today's commercial equipment.
 

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Feb 14/14