Modifications

Mods for President Grant (old) uPD858

I make a special EPROM expansion board that will add 4 more bands to many radios that use either Binary or BCD programming, it also adds a 10KHz shift function as well, click here to find out more.

It will give 1 band down, 1 band up, UK 40 (up 64 channels without Alpha ch hops), NZ 40 (down 63 channels) and 10KHZ shift.

On a 40 channel radio it will give coverage from 26.335 to 28.005 (including the normal low,mid and high bands of 26.515-27.855), that is a total of 167 channels !

I can also make a custom board upon request which will give whatever frequency range you want (within the limits of the radio).


MODULATION: Cut D23

POWER MOD:

1. Unsolder banded end of D21 and D22.

2. Add a 4.7K resistor across where D21 and D22 were removed.

3. Change R78 (15K) to 33K.

4. Change R84 (4.7K) to 2.2K.

5. Change C174 (56pf) to 82pf.

6. Change C173 (180pf) to 220pf.

7. Re-tune L32, L30, L29, L28 for maximum Forward Power.


Broad Band Modification


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