A couple things come to mine. First, you have a soft voice naturally so be sure to speak clearly and firmly. Speak into the mic and hold it in front of your mouth a few inches away. Check that you are not set for half deviation, not sure if the FT-2800 can do this though it's a problem on a lot of HTs. There might be a mic gain, if so increase in small amounts, say 5 steps on a scale of 100, until you get good signal reports.
"Silent enim leges inter arma." -- Cicero