UHF range

Exploder,

Keeping it simple.
The radio needs to see the other radio. If you were on top of a big hill and I was 30klm away on top of a big hill then we could talk.
If you were around the other side of a big mountain and I was on the other side 1lkm away we could not talk.

A .5w you could shout just as far. 5w and you have the range if you see the other radio.

This is very simple expiation but it will you an idea of how it works.

Wayne

If you did your test in conjunction with another quality in car unit the results would be totally different, the .5w can only hear as far as it throws :-)

Hi Exploder,

I'm no radio comms expert...but my (very limited)understanding of how radio and radiowaves work is......

When you said you tested the range of the .5W handheld with the 5W car mounted radio, it kinda occured to me that regardless of how powerful your car radio is going to be, it wasn't going to hear the very soft .5W transmission of the little handheld! The advertised power rating is for the transmit power of the radio.

The receive power is less than half that on most car mounted radios.
(and I think about 1/10th on some handhelds, with a switch to increase the recieve sensitivity on some??
I'm guessing around 1/2W - 1W, for most car radios(an expert will confirm/rebuff this)

So unless the transmission is powered higher to clear the hill, then not many devices will hear that 'whisper' of a transmission trying to overcome the hill!!

Even if you had a reciever that had 5W reieve ability, it would almost certainly need lots of filtering to remove any interference it will also pick up from various sources in the vicinity!

If your test Tx radio was a 1W or full powered 5W source then you may have heard it just a little bit longer, DOWN the other side of the hill!

If you can get your hands on a scanner, try using that next time too....
I think they have higher powered receivers, you may find th escanner may have heard the .5W transmission just a bit better(??)

then there are other environmental factors to consider too, like interference.........

......waiting now for the comms experts, to come along and 'shoot me down'......!

Well i guess there will be a lot of knockers on this one but on a few occasions between Hughenden and Julia Creek Richmond area just after sun up i was escorting trucks west on the Flinders Hwy and we were talking to and hearing trucks on the Landsborough Hwy near McKinlay , i checked the GPS for a straight line to Kynuna and it was 208 Klm, now this don't happen often ,The first time i experienced this freak reception was near Julia Creek back to the Shell at McKinlay and that was 108 Klm, please feel free to Call McKinlay Shell if you have any doubts'
About your hand-held well it depends on what power it is putting out and its quality,el-cheapo won't get farnor will it recieve well either, but a good DSE or Uniden with 5watts and you'll be surprised how far they do get out,

UHF's aint UHF's too Ex (as in oils aint oils) - re your in-car unit (have not tried the low power handhelds) - I recently upgraded my car unit to an Icom 400 pro - putting all the bells and whistles aside (its like a PC - there are configs and functions in there that go on for ever) it out performs the older GME unit by light years (but they are both 5W UHF's) - even though the GME had a premium antenna and a tidy setup. Innovations in radio design must be the go I guess.........

G'day Exploder

One issue which doesn't appear to have been covered above relates to your antenna.

You mention a 920mm. I reckon if you had a 150mm unity gain jobbie you would have got him over the hill.

Taller antennae transmit in a flatter narrow pattern perpendicular to the antenna over a greater distance, whilst shorter ones transmit in a rounder ball type pattern over shorter distances. Hence better for hilly areas or in convoy.

This info is available on one of the web sites, but I don't recall which (perhaps GME)

Food for thought.

Cheers

HI Exploder,

I have been in almost thje exact same situation. I have the Uniden 0.5w handhelds and mate has Uniden in car 5w (Sundowner UH-012???). In convoy it's great, if I get a bit ahead of him on a dusty road he loses me real quick but I can hear him clear as a bell. Chuck us into some hilly stuff and all things are equal - they're both useless!

Cheers
Scoey