Outer Limits 4x4 Board

Hiya radio gurus,

I have a question about the effective range from 3, 4 & 5W UHF radios. With all other things being equal - time of day, elevation/obstructions, antenna size/position etc how much extra range will a 4W UHF have over a 3W and then a 5W over a 4W?

I understand range is not a linear relationship with output power but I'm sure there is some formula to work it out.

Thanks.

Negligible.

If 5 W went 10 km, 3 W would get about 8-9 km.

It would take a power of 10 (ie 50W vs 5W) difference to double the range. (remembering it used to be possible for a 5 W, 27MHz CB radio to "skip" and be heard several thousand km away - this being a true reflection of what a decent signal path vs obstructions and other noise can do to effective signal propagation)

More difference would be made with the correct antenna selection.

Coincidentally the same applies for audio systems. Your 1000 W system is going to be not discernibly louder than your mates 800W system as the characteristics of the ear are "logarithmic" not "linear", more difference made by the efficiency of the speakers.