AJ1G
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« on: January 05, 2013, 11:50:06 AM » |
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I came across this oddity while doing my basement/shack cleanout. Think I picked it up at NearFest/Hosstraders at some point, apparently for $5.00 or less - someone had put that price on the front cover with a permanent marker...
It's a very tall (about 16") and narrow (about 8 inches square footprint) OD green military looking portable piece of test gear with a latched on front cover. Front panel contains a National style Velvet Vernier dial (made by someone else), a crystal oscillator switch, a variable oscillator switch, a corrector knob, a headphone jack, power switch, and a green pilot light. A storage area in the bottom of the cabinet contains a really long (at least 10 feet AC power cord)
The removable front cover contains a clip for storage of a small telescoping antenna that drops into the top of the cabinet, and a calibration chart that has the 0-100 range of the vernier dial as the x axis, and percent deviation, from .01 to at least 1.1 as the Y axis. The cal curve is a steep V which hits zero on the Y axis at 50 on the X axis. 50 is noted to be equal to 39.1 Mc, which is apparently the crystal frequency (actually a harmonic), the fundamental is in the 4 Mc range. No other information is provided by the chart.
I turned it on today for the first time, and it apparently is working perfectly, when I turn both oscillator switches on, I can hear a loud clean beat note that I can get to zero beat at 50 on the dial with the the corrector.
I suspect it was designed to be used in setting up a radio system, possibly FM, that operated on 39.1 Mc. Unit was made in 1945. Maybe for an early low band FM police radio system? Get nothing even closely related on a google search for it.
Very nicely made, high quality components, two small chassis behind the front panel, one for oscillators/detector and audio amp (4 tubes), and another for a power supply with a 6X5 rectifier. If not anything else, might be useful to power up a BC-221.
Anyone know any more about this thing?
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