Batboard

Does anyone know or know where I can find out what the max safe power output for a VHF motorcycle radio is? I keep hearing 15watts, but I also hear 15 watts for UHF, and 800.

15 watts is the pre-designated output that Motorola makes all their motorcycle radios at (all bands). I know I could turn up a motorcycle analog spectra to around 25 watts. What is safe for close human proximity, I really don't know. I would stay at 15 like the factory makes them at though, then you can't blame anyone but them when you get brain cancer. lol just kidding.

Jason

15 watts on all bands? As for safety, being able to call for help is good too.

Yup ALL the Motorcycle radios are labeled "15 watt configuration". If you have proper system infrastruction in place a 5 watt portable should work fine most times, therefore at 15 watts mobile with a gain antenna should work fine. Obviously if your talking direct comms then there you will notice a difference over 100 watt rig.

Jason

You must be located somewhere very flat. I live and work in a Geographically challenged county with 5 repeaters and numerous areas where there is no coverage from cars with 110 watt radios. The idea of having infrastructure that would support total coverage on a 5 watt radio is unthinkable here.

110w on a motorcycle? Could an alternator on one those even handle that kind of current draw?

They were limited to 15 watts because motorcycle batteries are small & dont have lots of amps. GARY N4KVE

So does anyone know what a safe power output would be for a VHF radio on a motorcycle?

Here is the FCC document on safe rf exposure, there is a chart about halfway down and a bunch of formulas, but the chart shows at 10 watts ERP safe distance is about three feet. And the lower the frequency the more your body absorbs.
http://www.fcc.gov/Bureaus/Engineering_ ... /oet65.pdf

Thank you that was what I was looking for, but not what I wanted to hear. I want to be 2 feet away and crank 50 watts. Oh well.

Go ahead if you really want to, but any increase in range will be minimal, even null.

15 watts or 50, your signal is not going to go where its path is obstructed...

Well, you might notice a difference from 15 to 30 (+3db).

But he says he is operating in a very hilly environment. My point was, that if he did increase power to 50 watts he still wouldn't see much (if any) improvement in performance in that kind of terrain (unless of course he's transmitting from the top of a hill).

The battery and charging system on the bike wont handle it (50 watt draw) very long.

A gain MC antenna will give you a little more. Most are 3dB gain, the ground plane sucks so they are a 1/2 wave. Looks like a 5/8 wave antenna though.

Fowler
KC5AEE

Thats what I have now.