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Cobra0020
Posted on Sunday, November 10, 2002 - 6:05 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

On Some of My cahnnels On Every Radio i have. Exe. Channel 14 When i go on it some of the people that are alittle low are like off freq. to me and the people that have alot on me i can here perfecly. does anyone know whats wrong in can't be my antenna of the radio could it be my area?
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2600
Posted on Monday, November 11, 2002 - 12:18 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Sounds like they are all 8-band "10-meter" radios. All Galaxy/Connex/Superstar radios with the MC145106 PLL chip use a crystal between 13 and 15 MHz. If I'm right and you have 8-band radios, the crystal frequency is almost exactly half the frequency of channel 13/14. You will probably find that this "birdie" carrier in your receiver changes frequency when you change from AM to USB to LSB. The older 5-band and 6-band versions of these radios used a crystal that puts this carrier up in the 10-meter frequencies above 28.0 . As a result, nobody notices that one. Putting eight bands in the radio required that they use a lower frequency crystal, and now the "second harmonic" frequency of that crystal will leak into the receiver, screwing up channels 13 and 14. The only cure I know is to get the crystal used in a 5- or 6-band radio and swap out the 13.56( or so) crystal that it came with. This doesn't remove the problem just moves it farther up in frequency, where it won't annoy you. I'm pretty sure the choices are: 14.01 MHz, 14.46 MHz, and 14.91 MHz. Doing this will cause you to lose one, two or three lower bands. You can use 15.360 MHz, but that will erase the four lowest bands, leaving you with no lowers at all.

The best way to be sure this is what you are hearing is to unhook the antenna and turn the clarifier end to end. If the carrier is still there, it's coming from inside the radio, not from the antenna.

73

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