You should do the same thing with an RFX-150 antenna when you extend it on Cat-5. What happens is the striped conductors, since they are twisted around the solid conductors, act as a shield from interference. The way they were intended for data transfer.

When using multiple RFX-150s, make sure that they are at least 50' apart or else their may be destructive interference between them.

Do not use an RFX-150 and an RFX-250 on the same MRF. Otherwise you will lose the benefits of the narrow band antenna. This seems like common sense, but you'd be surprised how many times I get asked this.

When using an MX-900/950/3000 or TX-1000, use the RFX-250. Better interference rejection, plus about double the range of an RFX-150.