In all directions? I would say the best would be a custom made VHF antenna tuned to the rail band. There are a few companies that make them. There was a company making collinear ground plane antennas for UHF AND VHF a few years ago, and I used the UHF version for GMRS and it ROCKED. I couldn't find the site though now...
Personally I would make a simple 1/4 wave dipole antenna and call it good.