It is possible to convert the receiver to a free running oscillator, but there are mechanical problems to be overcome as the oscillator and RF shafts need to be combined and a calibrated dial provided. As the receiver is AM, listening to aircraft is about the only use for the set unless it is converted to FM. Bandwidth of the I.F. is around 120 kc.
The tubes used include 12J5, 12C8, 9002, 9003, l2AH7 and 12SG7's.
The set has relay operated squelch. Some models had electronic squelch and 12H6 noise limiters.
The rack mounting is needed to provide mechanical drive to change channels.
The following formula is used to find the receiver crystal frequency:
F= fr - 12 (The I.F.) x 1000, divided by H
fr = frequency to be tuned in mc
H = crystal harmonic frequency
The crystal harmonic is frequency selected from the table below:
11 I00 -108 mhz
12 108 -116 mhz
13 116 -124 mhz
14 124 -132 mhz
15 132 -140 mhz
16 140 -148 mhz
17 148 -156 mhz
Audio output is from transformer 295. Terminal 5 is 50 ohms, 6 is 300 ohms and 7 is 4000 ohms.
The overall range of the transceiver is 180 miles at 20 000 feet.
© Ian O'Toole, 2009. Page created: 28/04/03 Last updated: 4/12/2009