there are 2 ways to get "extra" channels out of a
cb radio-- first way and its what your refering to with the cobra 148 is by changing programing on the pll or modifying it-- this is the common way to do it on
cb radios with modifiable plls
The second way is how you have to do it with radios with unmodifiable plls in them like your uniden 68--- that its by changing mixing xtals-- this is basically what is done with"expo" kits and such-- the kit is basically 3 xtals-- one for regular
cb fres, one for high freqs nd the other for low freqs-- a switch switches the voltage from on x tal to another
Its the same idea of taking out your 10,240 xtal in your uniden and putting in a slightly higher or lower value xtal-- its will give you differnt freqs
At this point in the game... xtals are not as easy to get as they used to be in the old days and this is why some guys just prefer to get the kits that come with the xtals-- all you have to do is find 2 xtals one thats 455kh higher the origonal and one thats lower-- but if I have something thats close i'll put it in and see what it mixes up
Anyhow on your radio thats what you have to do.... find xtals to change with your 10.240 xtal and mount them on a board with a switch to switch voltage between one and another
No big secret... just xtals are a pain in the butt to find and most of the time you have to order them.... in alot of cases an expo kit is cheaper-- thats why people just go with a kit-- its sometimes cheaper and a less pain in the butt to just order a kit than build one
So theres not really a mod to do it like on cobra 148's or other radios with modifiable plls-- the pll in your radio is not modifiable so you have to go to the xtal for channels
Take care
Hope it helped