UHF's power in (watts) question

Oh yeah as far as recomending one for your mate (to actually answer your question!) I'd tell him to get a real cheapie .5 watt (like a digitalk or similar) you should be able to pick one up retail for about $30, then save the rest of the money towards a decent car mounted jobbie.

I'm with you on this Jimbo. I gave my yaesu with the power cranked down to 20mw to someone who didn't have comms last weekend in the bush, coverage was great for the 100 or 200 metres we required...yes only 20mw. imusty will confirm this

Agreed. I have some expensive commercial Maxon hand held units which are programmed to output 5W - couldn't get over 500m from them in a High Country situation a couple of years ago when I needed to.

For car to car go with low power cheapies - they'll do fine for a few hundred metres.

Keep in mind: high power Tx = short battery life.

Mike Harding

PS. Mad Dog - good trip?

Yeah well I thought this guy may not shut up so I dropped it to 20mw to conserve our only batteries. As it was he was a bit mike shy but was starting to loosen up at the end of the day :)

Yeah good trip, bush camp with loads of fire wood, we named the camp timber loop because of the abundant firewood and the loop at the end of the track. imusty put the bus through a bit of water and up a moderately steep climb...he let out a yipeeee at the top. The bus goes well but wouldn't want to have to snatch it out.

There are some situations where the extra power may be an advantage (like triggering a repeater on a distant hill), but ultimately, UHF is line of site. So you are mostly limited by terrain, not lack of power.
I have a 5W Uniden mounted in the car, but I have three little hand helds which I lend to others in the convoy. These are completely adequate for most situations.

Mad Dog - so what frequency was iMusty transmitting on? :)

I have an Amateur Radio friend who you may well have heard on HF - he lives somewhat to the north of Melbourne and was telling me recently how he was chatting to the UK (on 20m) with 10mW (can't remember - might have been 100mW). However he does have an antenna system 195 feet high!

Don't worry about output power people - just get the antenna right.

Mike Harding

>So you are mostly limited by terrain, not lack of power

Absoutely Bob. Small amounts of power on vhf/uhf go many thousands of K's in free space, sometimes aided by high gain antenna arrays but not always. I can communciate with the International Space Station with 20 watts VHF when it's on the horizon at a range of 2000k using a whip on the ute. Sat phones signal must travel a long distance also. I Don't know if the phone sats are orbiting or geostationary but a geo stationary sat has to be ..awe gee what is it...35,000k high...or is it 32,000

Mike...cb ch 18...don't ask any more questions :)

That's true qrp but 195 feet high. I don't think the missus can climb that high :)

I am afraid I am going to have to disagree ith most of you.

Last trip we did a friend came along who didn't have a UHF radio, so he borrowed a 1w hand held.
We have a 5w vehicle mounted unit with an external aerial.
The third vehicle also had a 'standard' rig, 5w UHF and external aerial.

We found that the hand held internal in a car gave a range at most of 100m, down to 50m sometimes even when line of site travelling in convoy.

A real pain since the only vehicle that could hear them was the one closest. That vehicle then had to relay the message on.

A 4 , 5 or more vehicle convoy would be a real pain with that person missing out on a lot of comms. Worry is not knowing if they have heard the lead car on a trail obstacle, or turn instruction. (I know convoy rules should apply, but we all make a slip sometimes.)

As an experiment, we tried sending and recieving on the hand held back to a vehicle while walking in the bush. Level , but some scattered forest. Not dense rain forest. Range for clear reception went to about 150m.
Out to 350m, we could hear static, but not a voice.

If you want to use a 1w or 2w handheld for vehicle to vehicle, realise that tighter limitations apply and drive accordingly :-)

Hi John

I would hazard a guess that the 1W hand held radio is faulty in some way. One of the problems with the new breed of cheap low power UHF hand held CB radios is that they are designed and manufactured to a low price and, as such, I doubt much effort goes into ensuring they perform to their best capability when they come off the production line.

Providing you don't have hills or buildings between the two radios you really should be getting _much_ more from a 1W handheld that the numbers you mention. I assume the batteries were in a good state? And you should use either alkaline or NiCad/NiMh cells. Other types will tend to limit the output power.

I've just tried a test with a Jaycar hand held UHF CB, (DC-1040, which Jaycar bill as having a 1.5W output) using newish Jaycar AAA alkaline cells talking to my Maxon hand held (which is not really intended for CB) and that worked well across 500m of urban housing, a bit scratchy when the other end was operating from inside the vehicle but quite readable, audio quality improved when he got out of the vehicle, to be expected – both sets using standard antennas.

Mike Harding

John
the unit you had was obviously faulty. Our units work between cars up to about 3 km apart.