Which Japanese freq. has longest range on a Bit?

[mechanist]

I've got 2 of the ZipZaps right now. One on the 27Mhz and the other 49Mhz. The 49 has great range but the 27 is just crummy. Must be interferance in my area or something because I got another one from Radio Shack to try and it was very short ranged too.

So I'm thinking of getting a Bit from a hobby shop here that is using one of the Japanese frequencies.

Which of these frequencies seems to have the best range?
Does anyone know this or has figured it out?

Thanks for any info.