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).
The first thing that you need to do is find out the voltage used to control the PLL pins, i.e. 5 Volts,8 Volts etc. When you know what control voltage is needed you can proceed.
Cut the track that goes to pin 13.
Put a 4.7 K Ohm 1/4 watt resistor across the cut.
Now install a SPDT center off type toggle switch (i.e. it has three positions, UP, MIDDLE (off) ,DOWN).
Wire the top pin on the switch to earth.
Wire the middle pin on the switch to pin 13 on the PLL.
Wire the bottom pin on the switch to a constant supply voltage that is the SAME AS THE PLL PIN CONTROL VOLTAGE.
Now when you need to go to an 'A' channel do this:
For 3A go to CH 4 and flick the toggle switch down.
For 7A go to CH 7 and flick the toggle switch up.
For 11A go to CH 12 and flick the toggle switch down.
For 15A go to CH 15 and flick the toggle switch up.
For 19A go to CH 20 and flick the toggle switch down.
To go 10 Khz below channel 1 go to channel 1 and flick the toggle switch down.
YOU WOULD NORMALLY HAVE THE SWITCH IN THE MIDDLE POSITION UNLESS YOU WANTED TO USE AN 'A' CH.
OK thats it !
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