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Post by zcapri1973 on Jul 9, 2011 16:29:51 GMT -5
heres a tough one, im working on a united science labs tr-800 cb, made from 1959-1961. i have the sams (cb-1)! but it doesnt tell me what type of microphone it uses. the jack on the front for the microphone is a rca jack! is this a carbon, crystal, dynamic mike? any help with wiring or type of microphone would be great. it is one of the 1st modern cb's and im bound and determined to get it into working order. even a greater curosity is it appears to have a 2 tube amplifier of some sort mounted to the back of the chassis. a definite add on. an early cb'er trying to be a hammer? LOL. any additional info or pictures needed to figure it out, ill post asap. thanks to all in advance. Attachments:
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Post by zcapri1973 on Jul 9, 2011 16:31:55 GMT -5
I also found this picture online of this radio with a microphone setting on top of the radio like a mini speaker if this helps. Attachments:
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40sx
Mudduck
Posts: 39
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Post by 40sx on Jul 10, 2011 11:27:06 GMT -5
The microphone looks like an old Astatic crystal element mic. Wiring is very simple since the keying circuit is the lever on the left hand side of the radio. The hot or microphone wire would go to the center pin of the RCA connector and the shield or ground of the microphone would go to the outside casing of the RCA connector.
I have a couple of 1960s vintage USL Contact 23s. These radios have the large 4 pin connectors.
Dennis
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Post by zcapri1973 on Jul 10, 2011 11:45:41 GMT -5
thats a nice looking radio. i saw one on ebay that sold for $31.00 and worked fine! they said the same thing a non amplified crystal mike. so my next thing is to find a crystal mike. thanks for the info. i bought this at a antique shop for $15.00, there was just something about it, one of the 1st modern cb's as we know it.
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Post by cbrown on Jul 11, 2011 8:55:53 GMT -5
You're looking for high impedance microphone for that rig.
You could look for an Astatic D-104 head and mount it on a E-1 base. A lot of amateurs use that setup on shier old boat anchors.
You could also look for an Turner 254X, that was a Hi-Z crystal element. Just ignore the PTT.
A lot of harp players use Hi-Z microphones, so you can check music stores too.
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Post by zcapri1973 on Jul 11, 2011 20:32:13 GMT -5
thanks for the info cbrown, every bit of info helps.
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