These big antenna things you see

is there a diff between uhf and hf is there???LOL

laura b

Haha! So they say! ;-) I think HF is the REALLY long distance one??? Geez I'm gonna sound like an idiot! haha!

Scoey - 10 points.

UHF CB works on a high frequency (477 Megahertz) which essentially travels only a straight line, so you are limited to around 50 km max.

HF works on much lower frequencies (3 to 15 Megahertz) which bounce off the Ionosphere that is several hundred kilometres high, so signals can easily reach thousands of kilometres. It is nothing unusual to talk to to the other side of the world using the same amount of power as a headlight bulb. (Amateur band, not VKS737)

These lower frequencies have a longer wavelength and the antennas need to be much longer to have any sort of efficiency.

Mike

Interesting - funny how much easier it is to understand when you dumb it down good! Me gone done leared somethin' today! ;-)

Cheers
Scoey!

Mike, is 15 meg really considered to be the top end of the HF spectrum ? I've always understood it to be around 30 meg

True, the definition of HF is 3 to 30 MHz, but for VKS737, the highest HF frequency used is 14.997 MKz.

Mike

yep ok, I've been involved with radio since I was a boy. I thought the official definition may have changed and escaped me. God only knows what some fools will try and do these days.

Ray, you could have been right!! there is always someone trying to steal part of the spectrum, there is only a set amount of it and a heap of new uses for it at the moment! Michael

That be the big hooer's I was talking about! :-D

yeo that first one was the one i saw today. Seen other ones compared to the 2nd one too...maybe they were the first one just browny looking colour...

so that 910 one what does that do ; can ya use it for any mobile??

Cheers

Laura B

Those ones are generally used by people with too much money in their back account :)

Hi Ya Mad Dog.....I would say they are purchased by those who HAD too much money in their bank account. A new auto tune is around $1,500 I believe.....who wants to change taps all the time??

lol

hi Leigh, depends on how much frequency hopping one does I suppose.
In an afternoon of operating the ham bands I'd only change taps 3 or 4 times at most.

Thought you might have changed your screen name by now. Trust the Troopy is going well.

John is on his way back, at Bairnsdale now

No Laura, you can't use these for your mobile.

Short wave radio's should have antenna's that are much bigger than could be reasonably fitted to a 4WD. So they invented those automatic gadgets that fool the SW radio into thinking it is transmitting to a 'full' size antenna.

You could have antenna tuners for any kind of radio but since the higher frequenciey transmitters (UHF, mobile, etc.) have relatively small antenna's there's no point for a special external antenna tuner.

Klaus

Google is your friend for these kind of questions.
I just typed in "ham radio definition" and got lots of 'hits'.
Here is one of them: http://www.arrl.org/whyham.html

Klaus

Thanks Klaus.

Another question that has stumped nearly everyone I've asked is what does pH stand for. No shortage of answers as to what it is or what it measures, but the actual abbreviation is another matter.

I have googled it and now know, but try asking people who don't have access to a computer.

From my childhood chemistry days I recall it stands for potential Hyrdogen. The lower the number the more 'acidity' it is, like in a battery, the higher the number the more alkaline like caustic soda.
Ken

Spot on Ken. Surprising how many folks won't know that (like me before looking it up!).

V8, I''m buggered if I know what HAM stands for and I've been one since
1979 :) Lots of theorys around but who knows.