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Why


Some newer radios have the power supply's negative side connected directly to the chassis. If yours is built this way, it will still be connected to the negative side of the battery through the antenna's mount.

Older CB radios were built to work with a vehicle that had the positive side of the battery grounded to the vehicle's chassis. This was done in big diesel trucks until plastic radiators made it no longer necessary. Negative ground has been the rule for decades now, and the "floating" chassis radio that lets you operate in a positive-ground vehicle is an artifact of the past. If you unhook the black wire in an older CB, it will go dark. Newer radios have that black wire connected directly to the radio's metal chassis, and won't work in a positive-ground truck.

73
 
I do have the last SSB mobile model of a Sears Roadtalker (basically a Cobra 146 GTL) that will transmit the second you hookup the coax... I will have to get video of it this summer if we go out there and get some more stuff out of storage. :)
 
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Pretty sure you'll find it only does this with one mike. Sounds as if it has a short between the transmit wire and the shell of the mike plug.

And if you have another mike that fits this radio, I'll guess that it won't do this trick with the mike substituted.

73
I will have to try another mic once I get the radio again. Been since 2017 the last time I messed with the radio.
 

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