UHF gurus - 3/4/5W power difference affecting range?

All other factors taken into consideration as you mentioned.
An increase of 4 x power will double the distance. You would need to increase both ends of the path to achieve this.

Hello ben_gv3,

hope you don't mind an answer from your battery guru ;)

The distance gain factor in your examples is sqrt(4/3), or sqrt(5/4) equals 1.15 and 1.12 respectively.
Using logarithmic terms (allows you to compare distance gain with antenna gain), 10*(log(4/3)), or 10*(log(5/4)) equals 1.25dB and 0.97dB.

In other words, by using an antenna with 1.25 or 0.97dB higher gain than the existing one, you achieve the same outcome as an increase of power from 3 to 4, or 4 to 5W.
But note that either way, the increase in range is only 15 or 12%.

Hope this helps.

cheers, Peter

The biggest difference is the terrain you are in.

On some roads you can hear radios for a long long way On others barely around the next corner..


Most fixed UHF are 5w so put one in and be happy.

Get zapped by the latest solar flare and you wont have to worry LOL

Ben,
UHF radios should not be considered as anything other than short range devices. As others have said there are many factors that effect the range and they are changing all the time.

As Graham has said you are best to get a 5w unit and just accept that the range will vary.

If you are wanting a device with good range for safety reasons then you need to consider a sat phone or HF. Regardless I think anyone who goes into remote areas should always carry an EPIRB or similar. They are quite cheap now and equate in cost to a couple of tanks of fuel. Cheap for the security in the event of soemthing bad happening.

cheers

Just some useless information we used 2 GME TX6200 handhelds and got 93 kilometres as the crow flys with good voice and signal quality.

That was with the standard antenna on high power, we tried low power and still made contact but not as strong.

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Hi Alastair,

I am very well aware of the overall shortcomings of UHFs and do own an EPRIB so do know about their use. I am also very aware of the properties/characterisitcs of the different frequency ranges.

My initial question was purely on UHFs, nothing more and nothing less.
********************

Ben
My apologies if my well intended response upset you. I realise I went beyond your original question and made an assumption.

I think I am getting close to remaining silent on this site as I either cop abuse or upset people for reasons I don't understand.

regards