Yaesu 8900 Extended Transmit Mod


Yaesu 8800/8900 extended transmit mod

This is a “how to” I wrote a while back on how to mod the Yaesu FT-8900 Quad Band FM amateur radio.  It’s a great full featured radio that has passed the test of time.  It really hasn’t left me wanting more features than it already has.  I have used this radio in both mobile and home base applications and can say it’s a solid unit that can take a beating and keeps coming back for more.

I own a single radio and use it in multiple vehicles through the use of the remote faceplate mount and quick release mount.  I have dedicated antennas and power cords in each vehicle.  It literally takes less than five minutes to move the radio from one vehicle to the other.

Before I begin I want to make it clear that if you decide to modify your radio you are moving into a gray area of legality.  The reason I originally modified my radio was that I provided communications for a Baja 1000 team and the frequencies that are used require “out of bounds” programming to the radio.  There are also those that believe having the capability to transmit in the extended frequencies are a good to have in the case of emergency situations.

OK, here’s the down and dirty.  If you kill your radio, don’t come crying to me.  You are on your own.

First, remove the radio from your vehicle and get set up in a comfortable place with good lighting.

You will need the following tools (no soldering iron is needed).
– small phillips head screwdriver
– small needle nose pliers

1. Remove the (8) screws on the cover of the radio. There will be two on each side and four on the top. Do not remove the screws holding in the speaker. In the picture you will see four large screw heads. These are for my quick release bracket (which I highly recommend). The arrows just show where the screws are located to be removed.

1 Radio overview


2. As you remove the cover, the speaker connection will have to be removed. Just give a slight tug on the wires and they will easily come unplugged. Set the cover aside.

FT8900 cover with speaker


3. Now position the radio so the front is facing you. On the far left corner facing you is a row of diode slots. There will only be two diodes installed. All the other instructions I have read say that it is necessary to use a soldering iron to remove the diode. Good luck with that! The diodes are tiny.

All I did was use a pair of small needle nose pliers to crush the diode. This worked wonderfully and took about a second.

I have indicated in the picture the diode slot strip in the rectangle and the arrow shows the diode that needs to be crushed.

3 diode position


4. That’s about it as far as the mod goes. Reconnect the speaker and screw the cover back on.


A. Don’t freak out when you go to turn the radio back on. The radio does a factory reset. All the indicators on the display will light up and then show your original factory settings.

B. All your programming will be lost! I use the following software for programing. G4HFQ Radio Programming Software
It works great and gets good reviews over the junk Yaesu recommends. I just reprogrammed my radio to what is was before.

C. You will have to change the radio type from a drop down menu in the software if you are using that to put programming back in. My radio type went from “81” to “80” after the mod.

Here is a list that shows the resulting frequency ranges you have access to once the modification is completed.

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

That’s it!  Please don”t be an idiot and do stupid things with your radio.  Be responsible, get licensed, and enjoy a great and useful hobby.