Yaesu FT-991 Mars/Cap Mod Control Unit Access Instructions

Yaesu FT-991 Mars/Cap Mod Control Unit Access Instructions

This information is solely for use by licensed members of MARS (Military Affiliate Radio System) or CAP (Civil Air Patrol), and release to any other party is not authorized. Use of any Amateur Radio product outside of the Amateur band is at the users own risk, and no guarantee of compliance with specifications outside the Amateur bands is expressed or implied. The Limited Warranty does not cover damage caused by any attempt to modify an apparatus for out-of-Amateur-band operation, nor does the Limited Warranty cover damage to components that may result from out-of-Amateur- band use.

Modification Procedure:
Remove the bottom cover. On the CNTL-UNIT, place a solder bridge across the pads at JP3003, expanded transmission will be engaged. See the images below for location details.

After MOD

Before MOD

Make a note of all your Menu settings, so you can re-load them quickly, then do a hard CPU reset in order to save the new frequency range. To do this, turn the transceiver off, then press and hold in the [FAST] and [LOCK] keys; hold them in while turning the radio back on. When the radio comes on, you may release these two keys.


ORIGINAL TX FREQ. RANGE: 160-6M AMATEUR BANDS

NEW TX FREQ. RANGE: 1.8 – 30, 50-54 MHZ



Yaesu FT-991(A) Users Group (groups.io)
https://groups.io/g/Yaesu-FT-991