Really you [and I] should consider having a small jumper of more flexible coax a few feet long so that the connector doesn't have the strain of the LMR400 on it. But, considering how much better only 50 ft of LMR-400 did for my reception, I didn't want to substitute _any_ of the length with lesser cable.
Mike
Don't worry about a problem using a short jumper. Our radio installers put them on the end of hardline going into the radios at the FD.
Mike