Cobra 29GTL, 29LTD and Uniden PC76
The PLL is not modifiable when used in an AM only radio, the only method that will allow more channels is to disconnect the 15.360 Mhz signal that is coming from a tripler circuit and replace it with another one depending on the required freq. range.
Here are the instructions:
Lift one end of C87 (the side closest to IC2), then connect a switch's common pin to the open pcb hole, connect the "modified" switch position to a crystal oscillator (you can find a one you can build inside my build it / projects pages or just click here), then connect the "normal" switch position to C87, all you need to do is get a crystal to use for the oscillator, the original frequency is 15.360, you add / subtract the number of channels to / from the frequency
Say you want 26.515 - 26.955 (the low band) just deduct .450 from the original freq (450 khz = 1 band of channels), so a crystal of 14.910 Mhz will give you the low band.
OR to get 27.415 - 27.855 (high band) you will need a 15.810 Mhz crystal.
You may actually use both but the radio may not cover the freq. range ( due to limitations in the tuning circuits for the broadband requirements)
The only hard part is finding a supplier for the crystal, the mod itself is easy !
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