High Band GE Custom MVP (Exec II) 222 Mhz Conversion
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by Mark Gilmore, WB6RHQ
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High-band GE MVP/EXECII Exciter on 220 Mhz (19D423293G2)
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Remove the cans from T105, T106, T107 and T108
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Remove the T107 and T108 coils
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Remove T105 and T106 coils and install them in the T107 and T108 locations
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Remove all but 3 1/2 turns from the T107 and T108 coils and install them in the T105 and T106 positions
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Remove R134 and L107. R134 may already be missing
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Replace R130 with a jumper
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Replace the following with the new values shown:
C138 - 6.2pf
C139 - 5.1pf
C141 - 3.9pf
C146 - 13pf
C147 - 6.8pf
C149 - 22pf
R101 - 100 1/4 watt
R126 - 470 1/4 watt
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Install a 1.8K 1/4 watt resistor, from the base of Q108 to the intersection of L108 and C144, on the bottom of the board.
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Reinstall the coil cans.
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Notes:
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The last doubler, Q107, is now a tripler
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The new crystal formula is: xtal = f/18. Calculate the fundamental frequency and put it back into the original crystal formula. Order the equivalent high-band frequency.
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High-band GE MVP/EXECII Receiver on 220 Mhz (150-174 MHZ)
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Oscillator Multiplier Board (19D423241G1)
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Install a 12pf capacitor in the space reserved for C412
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Install a jumper between the bottom two turns of L403 closest to the position reserved for C417
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Install a jumper from the center of L403 to the next turn, closest to R413
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High Band Adapter Board (19B227258)
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Remove C460
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Mixer Board (19C320153)
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Install a jumper from the center of L502 to the first turn of the inductor going towards C504
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Install a jumper from the bottom center turn of L502 (closest to the gate of Q501) to the ground plane to the right of L502 and below C502
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RF Assembly (19D416693)
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Remove the helical resonators L301/311, L302/L312, L303/313, L304/314, L305/315, L306/L316 and L307/L317
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Remove 1 3/4 turns from the cold end of each resonator and reinstall. A soldering iron in the few hundred watt range is required to complete the procedure
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