To extend TX range on a Yaesu FT-3 or FT-2 is very simple and quiet risk free, but you will lose your warranty! The new TX frequencies will be 140-174 and 420-470 MHz.
First! Take a backup of you settings and memory channels, you will lose them!
Hold down DISP for about one second to enter the config menu, then go to SD card and then Backup, click on Write to SD. Shut down the radio and put your SD card into a computer and save the settings. I you don’t know how to do it, read this
Back of the radio under the battery, there is a small round rubber top. Peel it off and under that you will find a singel 0 ohm resistor.
Very careful, remove the resistor with a soldering iron. Do not just bend/break it with a screwdriver! After that, put the rubber back on and the battery. Insert the SD card again.
Now it’s time for a factory reset. Hold down BACK, DISP and BAND and then turn the radio on.
You don’t need to change any settings as you will restore all you settings and channels that you had before. Again, go into the SD card menu and Format the card (you need to do this). After it’s done, turn off the radion and insert the card in the computer.
Now, save you old settings/channels to the new formatted card (overwrite the BACKUP-file on the SD card). Again, you find it here if you don’t know how to do it. Insert the card into the radio and in the SD card menu, press Read from SD. You now have all the settings and channels as befor with extended TX.