Is there a mars modification that can be done on the Yaesu FT-991A that will open up the full US 70cm band, From 420.000 MHz to 430.000 MHz, because for some reason that portion of the band is locked?
There is not an approved mars mod that does what you desire. Yaesu’s approved Mars Mod opens 1.8 to 30 mhz continuously, but does not change 6M, 2M, or 440 (70CM).
Well what is the unapproved mare mod that will fix this? I’m not asking for illegal frequencies I’m wanting frequencies that we are allowed to use.
You may want to contact Yaesu Support or one of many amateur radio equipment repair locations/individuals.