Yaesu ft-8900

Not quite sure how you would accomplish that since after the Mars cap mod this is what you are left with.
FT8900 mod will only open up the VHF and UHF transmit (see below)
The Lowband Rx/Tx remains 28-30MHz and 50-54Mhz.

FT-8900 Range:
28-30Mhz Rx/Tx
50-54Mhz Rx/Tx
108-180MHz Rx
137-174MHz Tx
320-480Mhz Rx
420-470MHz Tx
700-823.9875MHz Rx
849.0125-868.9875MHz Rx
894.0125-913.9875MHz Rx
939.2125-958.9875MHz Rx
984.2125-985MHz Rx

 

There is no mars mod for this radio, the only mod will open the upper bands up but that’s it, the radio is not meant to be used below 28mcs and unless you want to do some firmware programming just to listen, you are stuck with the multitasking FM only radio.

 

The ft-8900 would be useless on the cb band even if you could modify it to work on 27 mhz, because the majority of cb operators are on AM & SSB which the ft-8900 doesn't have. So it sounds like you are trying to kill two birds with one stone ( which is a good idea), I would recommend going with the yaesu ft-857D. Yes it will cost twice as much as the ft-8900, but it will give you all the operating modes you need for cb and the ham bands. The mod for this radio to talk on 11 meters maybe a drawback....from what I understand you need a tweezer type soldering iron to remove a smd jumper....not easy task for most people. Now some people might think your foolish for using a $700 radio on 11 meters, but since you are wanting to use it on the ham bands too, I don't see why that should be a problem. I think a lot of drivers have about that much money tied up in a 10 meter export radio after they have them modded to work on 11 meters, and an alignment done. Anyway its just a suggestion.

 

I have my Icom IC7100 in my Wrangler opened up for use with a Lil' Tarheel screwdriver antenna, <1.5 SWR anywhere I choose to go, but honestly, for CB the Stryker 447HPC2 and Lil' Wil in my wife's car, which we use for long trips, is a much superior choice. The receiver on the Stryker is phenonmenal, and I've found I'm really not using the ham HF mobile as much as I'd hoped in the Wrangler. I'm seriously considering moving the 7100 to our MN cabin and installing a Stryker 94HPC compact in the Jeep to complement the Alinco VHF/UHF rigs that we have in both cars. I'd put in another 447, but space is an issue..

 

The FT8900 won't work on 11 meter AM which is where the CB is.