The Yaesu FT3DR Mars Modification adds frequencies outside of the ham bands. These are used by MARS and CAP operators. The stand for Military Auxiliary Radio Service and CAP, which is the Civil Air Patrol. The MARS organization passes personal military traffic. The CAP organization conducts search and rescue operations.
This MARS/CAP modification is for authorized personal only, and one should be a member of one of these organizations. All unauthorized use of these frequencies are prohibited. The FT3D comes with an easy access hole to perform the mars mod.
How To Perform The Modification
The first thing you want to do is save your frequencies to a memory card. Then you want to remove the battery and look for the small black rubber plug in the image below. The hole diameter is the size of a #2 pencil eraser.
Lift the top lip, push inward and lift. Be careful not to puncture it. Also, the metal surface scratches very easily. You will see one surface mount resistor marked “000”. This is the one you remove. This resistor sits inside a hole in RF insulation making the use of a thin tipped heated tweezers necessary.
My set of heated tweezer tips was too thick so I used my thin tipped iron and fine tipped ESD tweezers. I used a small amount of Chipquick to assist the removal. Take care not to over heat the board. After removal of the resistor you can use contact cleaner and a small Foam Qtip to clean the area. You should see the two clean pads.
When finished with the removal just reinstall the plug. Make sure it sits flush and reinstall the battery. You will need to do a full reset of the radio. With the radio turned off, you will need to hold the back, display, and band buttons down while turning the radio on. The radio will ask if you want to reset all, click OK and it will reset to where you have to add a callsign(like new).
Then reinstall the sim card and upload your saved settings and frequencies.
The Yaesu FT3DR Mars Modification
This modification will successfully open the transmit frequencies outside of the ham bands on the FT3D. Make sure you are authorized to use these frequencies, and have it done at an authorized shop to maintain the warranty.