Converting a 900Mhz Motorola Spectra for use on the 33cm Amateur Band.  

Open the spectra to expose the bottom of the VCO and the RF board.


Remove the VCO cover to expose the bottom of the board as shown above.


The VCO Steering Line voltage must be pulled lower with the addition of a resistor.
Locate the pink chip capacitor above. The left side is where our resistor connects.
The other end of the resistor goes to ground.


I begin by placing a small drop of solder on the pass through hole as shown.


Pick the necessary resistor to drop the steering line voltage to where the VCO locks.


I place a small chip resistor from the ground point to the chip capacitor as shown.


Pick the necessary capacitance to bring the deviation level up to where it should be.


The capacitor should be placed across the chip capacitor and soldered.


This is the completed modification for the 900MHz Spectra.

Re-Install the VCO cover, and the access plate.

Do not remove the Hear Clear board from the radio's Command Board.

Program the radio and ensure you disable HEAR CLEAR and COMPANDERING
under the radio-wide change code plug options.

Align the radio as normal to factory spec.

Enjoy your 33cm Spectra.

 

 

 

 
 
   
   
   
   
   
   
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