I've owned the Kenwood TH-D74 since the first week it became available and finally decided to perform the extended transmit mod. Some of the sites that have already published this mod make it seem like a big deal, but it's really pretty easy. Here are the steps:
1. Remove the antenna and rotary knobs on the top right. The rotary knobs just pull off.
2. Remove the SMA nut. If you plan on doing this type of work for all types of HTs, you should consider purchasing the proper tool for the job. I use one of these inexpensive $7 wrenches that you can find on ebay: https://www.ebay.com/itm/310808572946?rmvSB=true. After the knobs and SMA nut is removed, your radio will look like this:
3. Remove the battery and the four screws holding the aluminum back to the radio body.
At this point, the front cover can be easily be removed from the body. You'll need to unhook the rubber PTT cover from the main chassis, which was already done in the pic above.
4. Once you separate the radio cover from chassis, lay the cover down on its face. There is a ribbon cable connecting the buttons to the main board; most of the instructions published want you to disconnect this ribbon cable but it is completely unnecessary.
5. On the main radio board, remove R761. I just used a fine point soldering iron and it came off easily.
Reassemble the radio, reset it and you're good to go. Here is the TX range after the mod:
136-174 Mhz
216-235 Mhz
410-470 Mhz.
I have not noticed any ill side effects from performing this mod.
1. Remove the antenna and rotary knobs on the top right. The rotary knobs just pull off.
2. Remove the SMA nut. If you plan on doing this type of work for all types of HTs, you should consider purchasing the proper tool for the job. I use one of these inexpensive $7 wrenches that you can find on ebay: https://www.ebay.com/itm/310808572946?rmvSB=true. After the knobs and SMA nut is removed, your radio will look like this:
3. Remove the battery and the four screws holding the aluminum back to the radio body.
At this point, the front cover can be easily be removed from the body. You'll need to unhook the rubber PTT cover from the main chassis, which was already done in the pic above.
4. Once you separate the radio cover from chassis, lay the cover down on its face. There is a ribbon cable connecting the buttons to the main board; most of the instructions published want you to disconnect this ribbon cable but it is completely unnecessary.
5. On the main radio board, remove R761. I just used a fine point soldering iron and it came off easily.
Reassemble the radio, reset it and you're good to go. Here is the TX range after the mod:
136-174 Mhz
216-235 Mhz
410-470 Mhz.
I have not noticed any ill side effects from performing this mod.
