I'd just use a larger cable such as RG-213. The losses
should be small enough not to worry about as long as the
SWR isn't excessive.
You can use VK1OD's transmission line loss calculator here:http://www.vk1od.net/calc/tl/tllc.php
to compare the losses of various cable types and lengths.
100' of RG-213 has less than 1dB of loss, while the same
length of RG-8x has just over 1dB. Either would work fine.