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).
G.E.
3-5804D,3-5811B,3-5812A,3-5813B,3-5819A
Midland
76-858, 76-863, 76-886, 77-830, 77-838, 77-849, 77-857, 77-882,
77-888,
77-899, 77-955, 77-963
And just about anything with a PLL 02A chip in it.
The 23-channel radios will give different channels.
There are a few different mods using the same type of switching method, here they are:
PS, I have edited these to make the mods MUCH easier to do and understand, as well as more usefull !
Coverage between 25.685-26.125 on channels 1-40 (-128 channels)
Note: The radio will need a re-tune to change coverage by this much !
1) Cut the trace going to PIN #7 and #8.
2) Solder a 4.7 K resistor across each cut.
3) Solder one of the common pins of a DPST switch to earth.
4) Solder the other common pin to pin #1.
5) Solder from pin #8 to the pole of the switch that goes to earth (marked
as "A").
6) Solder from pin #7 to the pole of the switch that goes to pin #1. (marked
as "B")
With the switch on the mod is activated.
Coverage between 26.325-26.765 on channels 1-40 (-64 channels)
1) Cut the trace going to PIN #7, #8 and #9.
2) Solder a 4.7 K resistor across each cut.
3) Solder one of the common pins of a DPST switch to earth.
4) Solder the other common pin to pin #1.
5) Solder a jumper wire across pins #8 and #9
6) Solder from pin #8 and #9 to the pole of the switch that goes to earth (marked
as "A").
7) Solder from pin #7 to the pole of the switch that goes to pin #1 (marked
as "B").
With the switch on the mod is activated.
Coverage between 26.645-26.955 on channels 1-27 (-32 channels)
1) Cut the trace going to PIN #7, #8, #9 and #10.
2) Solder a 4.7 K resistor across each cut.
3) Solder one of the common pins of a DPST switch to earth.
4) Solder the other common pin to pin #1.
5) Solder a jumper wire across pins #8 and #9.
6) Solder a 1N4148 diode between pins #10 and #8,#9, with the banded end toward
pin #8 and #9.
7) Solder from pin #8,#9 to the pole of the switch that goes to earth (marked
as "A").
8) Solder from pin #7 to the pole of the switch that goes to pin #1 (marked
as "B").
With the switch on the mod is activated.
DPDT switch shown from rear
-----
| o o |
Earth -------------|-0 0-|---------- Pin #1
"A" -------------|-0 0-|---------- "B"
-----
Coverage between 27.285-27.595 on channels 1-27 (+32 channels)
1)Cut the Trace going to PIN #10.
2)Solder a 4.7 K resistor across the cut.
3)Solder the common pin of a SPST switch to earth.
4)Solder one of the other pins of the switch directly to pin 10.
With the switch on (connecting pin 10 to earth) the mod is activated.
Coverage between 27.605-28.045 on channels 1-40 (+64 channels)
1)Cut the Trace going to PIN #9.
2)Solder a 4.7 K resistor across the cut.
3)Solder the common pin of a SPST switch to earth.
4)Solder one of the other pins of the switch directly to pin 9.
With the switch on (connecting pin 9 to earth) the mod is activated.
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