Larger wire means lower voltage drop and you should be able to run further without having to use a local power supply RFX-250. The other concern is capacitance of the wire pair you use. The lower the better. Cat-5e is well-specified. 18-2 wire is typically used for audio work and I am not at all familiar with their capacitance specifications.


RG-6 should work just fine and over a much longer distance. RG-6 has only 1/10th the resistance per foot as a CAT-5 pair. Of course, RG-6 is expensive and bulky for new installs. In a new install, CAT-5 with a local power supply for the RFX-250 is probably cheaper--and you still have three unused pair remaining in the CAT-5 which could serve for carrying video (as I did) or Ethernet. But if you happen to have a cable in place, it'd be a great cable to use (I think, I have not tested it myself.

The RFX-250 uses an unbalanced output. The issue of unshielded or untwisted wire is a different matter and really depends on the noise in your environment. I wouldn't hesitate to use coax for a run. I'd be hesitant about anything else without understanding the cable and the environment it is run in.


There's no such thing as a perfect cable. Each type has its place and that's why there are so many. The big advantage of CAT-5 is cost, diameter, flexibility and that it is so widely used. Lots of people are using it for purposes other than its original design intent. So long as we understand its advantages and limitations, that's fine. But for bulletproof installs, the characteristics of the devices and the cable medium need to be understood and respected.


Unless you can be certain of the environment, I'd use a local power supply for any RFX-250 installed over long wire runs. How long is long? I'd hesitate to use more than 100 feet of CAT-5 and maybe 200 feet of RG-6. Those are simply guesses. The point is this: an RFX-250 at ten feet does not need a separate power supply. An RFX-250 at 600 feet does. Where the cutoff is depends on the circumstances. I want bulletproof operation, so I'll use local power supplies for longer runs. That completely removes one variable.

Please remember, it is ESSENTIAL to use the decoupling capacitor at the RFX-250, even when it is only 10 feet away. I saw real examples of improper operation without the added capacitor at even a ten foot distance. The malfunction shows up as the RF light flickering on and off or simply staying on for long periods. Installer naturally think it is an RF problem. In most cases, it is simply an issue of power supply that a decoupling capacitor cures.