UHF Radio Feedback

I have finally installed the CB and all seems to be working well with a Uniden AT470 6 DB Gain antenna.
However, I am using a Uniden UH075 5 watt handheld as a home base and can only manage around 5km distance between the UH089SX and my handheld.
Is this a normal range and if so, how can I extend it? Would a larger antenna for the UH075 be an option and if so, which one?

cheers
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Reply By: flyboy - Thursday, Feb 07, 2008 at 22:39

Thursday, Feb 07, 2008 at 22:39
Marclau,

Range is dependant upon a lot of things...

UHF communications relies on "Line of Sight", i.e, any buildings, terrain, etc in the path between TX & RX will attenuate the signal.

5 Kilometres does not surprise me, assuming you are speaking about simplex communications and not duplex, i.e using one of the repeaters, which is designed to extend the range considerably.

Also be mindful that a handheld has an inefficient antenna, so yes, you are correct in saying that another antenna may help, but be aware that other things come into effect. For example, if you run a considerable length of standard RG58 type coax, the losses are quite considerable at UHF frequencies and it is quite possible that you could end up with considerably less than your 5 watts going into the antenna.

For a range of base station typem mobile and handheld antennas, have a look at www.rfi.com.au. They can also advise you on the different types of coax, mounting arrangements for base antenna's, etc.

Cheers
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Follow Up By: Member - Doug T (FNQ) - Thursday, Feb 07, 2008 at 23:21

Thursday, Feb 07, 2008 at 23:21
flyboy
Buggered if I Know why people have this ingrained idea about line of sight, I been using UHF for......YONKS... and while travelling all over Aust' in all terrains I have recieved and talked to traffic controllers up to 16 Klm , anyone know the New Norcia Terrain ... would know about the trees and hills, I could communicate with roadworks 9klm away to let them know about the oversize loads , then there was the time we ( the convoy ) communicated from the rail Xing 13Ks East of Hughenden to a site near Nonda on the Flinders Hwy, 194Klm , just after Sunrise.

.
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Follow Up By: Member - Davoe (Yalgoo) - Friday, Feb 08, 2008 at 08:17

Friday, Feb 08, 2008 at 08:17
Yea doug maybe it isnt strictly line of site but anyone working in open pits will tell you you cant commmunicate with the office 2km away without a repeater from the bottom of the pit. On the other hand from the top of Mt pasely (cape arid NP) i have talked to a truckie on the Eyre highway - over 200km.
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Follow Up By: Member - Doug T (FNQ) - Friday, Feb 08, 2008 at 08:33

Friday, Feb 08, 2008 at 08:33
Davoe
I'm not in a pit, and I wasn't on a mountain thus I will treat your comment with the contempt it deserves .
Whenever there's a debate about people always have to go to the the opposite extremes, I'm not a Miner or a mountain climber.
And for Mikes interest I don't climb bloody trees.

.

.
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Follow Up By: Mike Harding - Friday, Feb 08, 2008 at 08:39

Friday, Feb 08, 2008 at 08:39
Not restricted to line of sight at UHF eh? It's probably because you were using an Icom radio and not a crappy Uniden Doug.

Mike Harding
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Follow Up By: Member - Doug T (FNQ) - Friday, Feb 08, 2008 at 08:44

Friday, Feb 08, 2008 at 08:44
Mike
Good to see you've got down from the tree and have actually learnt something.

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Follow Up By: Member - Doug T (FNQ) - Friday, Feb 08, 2008 at 08:52

Friday, Feb 08, 2008 at 08:52
Davoe
Just read your comment again..... So your going to tell me the radio signal will travel from the pit to X amount of Ks to a bloody repeater then back to the office, but you can't contact the office direct at just 2Klm,
Oh and the Repeater wouldn't be line of site either...just like the office , get a better radio or another job ,

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Follow Up By: Member - Davoe (Yalgoo) - Friday, Feb 08, 2008 at 09:07

Friday, Feb 08, 2008 at 09:07
dunno why all the aggresion but heres open pit radio coms 101 for you
- yes the repeater IS line of site. They either sit at the pit edge or on a nearby waste dump with LOS INTO THE PIT.
this allows the repeater to also have LOS to the office.
But also as i said in my original reply UHF isnt strictly line of site you can get a fair way down in a pit before repeaters like i have mentioned are neccessary.
- and mt pasely is actually a granite rock - hardly a mountain
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Reply By: flyboy - Friday, Feb 08, 2008 at 00:27

Friday, Feb 08, 2008 at 00:27
Doug,

I don't dispute what you are saying, however VHF and UHF signals do travel line of sight and the quality of the signal is effected by buildings, terrain, etc. On the open road, yes the distances you are talking about are no big deal, sometimes on VHF and UHF under freaky conditions communications up to a couple of 100's kilometres can be possible, but not common.

2 examples to clarify...Tree's effect the signal quality of a GPS, these frequencies are much higher than UHF so are more effected. Also, if you have a listen to your AM car radio at night, quite often you can hear interstate radio stations...this is because low frequencies rely on a layer of ionised particles above the earth called the ionosphere, which "refract" or bend radio signals, causing multiple "skips" of the radio signal. This is also why "Skip" is commonly available on 27Mhz CB radio, big difference between 27 Mhz and 470 Mhz when it comes to distance you can talk point to point, without a repeater.
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Follow Up By: Member - Doug T (FNQ) - Friday, Feb 08, 2008 at 08:41

Friday, Feb 08, 2008 at 08:41
flyboy
Yeh well I'm pleased you don't dispute what I say because I detest being called a liar when I've had personal experience with equipment.
After 32 years owning and using CBs, was going for the amatuer licence and was 5 weeks short of the exam when I landed a job with a transport Co and let it go, I also install my radios myself .

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Reply By: Marclau - Friday, Feb 08, 2008 at 00:44

Friday, Feb 08, 2008 at 00:44
So a change in antenna for my handheld may assist then?

Am I right in runninga a coaxial to an external base antenna do the trick then?

Or should I consider simply buying another CB radio as the home base or is my handheld 5 watt UH 075 Uniden good enough?

I would also like to add that at night time, with the handheld, I have managed to speak with people up to 25kms away and that is also remaining indoors with the handheld.........
AnswerID: 286265

Follow Up By: Member - Kiwi Kia - Friday, Feb 08, 2008 at 06:35

Friday, Feb 08, 2008 at 06:35
Roughly, any range in excess of 1 km per watt output of your UHF is a bonus if you are not useing a repeater. You could spend lots of dollars and not get any significant extra range.
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Follow Up By: Mike Harding - Friday, Feb 08, 2008 at 08:25

Friday, Feb 08, 2008 at 08:25
There is no point in buying another CB if your handheld is capable of 5W and the battery is capable of supporting that power. The only way to improve matters is to fit an external antenna to a point as high as possible, there are many, very simple, designs for UHF antennas and if you mainly want to Tx/Rx in one direction consider an antenna of the Yagi design. You do not have to buy a commercial antenna - they are easy to make, do a web search. HOWEVER... you MUST use high quality co-axial cable to connect the radio to the antenna. I cannot remember co-ax numbers (don't! use RG58) but expect to pay $3 or $4 per metre for it. I'm sure others will be able to suggest part numbers.

Mike Harding
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Follow Up By: Member - Mike DID - Friday, Feb 08, 2008 at 19:03

Friday, Feb 08, 2008 at 19:03
At UHF CB frequencies RG58AU 1/4inch coax will lose half your power over 7 metres. RG8A 1/2 inch coax will lose half your power over 14 metres.

Keep in mind the inverse-square law applies - if you halve your power you will get 0.7 the distance.
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Follow Up By: Marclau - Monday, Feb 18, 2008 at 20:51

Monday, Feb 18, 2008 at 20:51
Anyone able to assist with regards to the best Coax for my base station antenna?
Mayb also the right antenna........at this stage (due to health) I wont be making any agttempt to build the antenna myself but am considering the Mobile One COL9 Base Antenna.

Anyone had any experience with one of hese?

Looking at placing this on my roof and running around 7-8 meter cable to my base Uniden UH075......:)

All feedback welcome......

PS Will be happy with 10-12km range now too.........fingers crossed.
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Reply By: Member - MUZBRY (VIC) - Friday, Feb 08, 2008 at 11:28

Friday, Feb 08, 2008 at 11:28
Gday
After reading all that , i'll have to have a Bex and a lie down.............

Muzbry
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Follow Up By: Member - Chris G (VIC) - Friday, Feb 08, 2008 at 13:10

Friday, Feb 08, 2008 at 13:10
Hi Muzbry
I bet he's sorry he asked

Old Bill
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Follow Up By: Member - MUZBRY (VIC) - Saturday, Feb 09, 2008 at 09:22

Saturday, Feb 09, 2008 at 09:22
Gday
Now Chris, this is serious stuff , so we arnt supposed to make lite of it. You young fellas will never learn.....
Muzbry
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Reply By: obee - Friday, Feb 08, 2008 at 14:38

Friday, Feb 08, 2008 at 14:38
thank goodness UHF does not travel very well or I have to listen to all of the above all of the time.\\

Owen

AnswerID: 286350

Follow Up By: Mike Harding - Friday, Feb 08, 2008 at 17:00

Friday, Feb 08, 2008 at 17:00
I'm a bit perplexed by you people: you open a post which is clearly asking a technical question about UHF CB and then you bitch that responses to that post are providing information about UHF CB? What did you expect? Replies to the effect of:

"well, yeah mate it's, like the radio waves things ain't it"

perhaps?

Mike Harding
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Follow Up By: Member - Mike DID - Friday, Feb 08, 2008 at 18:44

Friday, Feb 08, 2008 at 18:44
. . . and when they argue that UHF CB is NOT "line-of-sight" they're most probably assuming that "line-of-sight" used for radio propagation, means "I can see the other aerial with no obstructions in the way".

We can only try to explain the technology to them !

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Reply By: MEMBER - Darian (SA) - Friday, Feb 08, 2008 at 15:27

Friday, Feb 08, 2008 at 15:27
I'm just getting into the same boat - Icom 400 pro in the car and a GME 5 watter for walks away from the car - if I go for a solo stroll in the bush, I can comm with the lady of the expedition while she stays in camp - I got selcall and CTCSS setup betwen the units - hell - it might all work ! Have not really filed tested it to date, but I'd be happy with 5k - pure line of site would be better than that I guess - the stubby antenna on the HH must be a compromise - there is a longer antenna available for my HH but that somewhat defeats the prime purpose of being compact - the antenna would be up my nose or broken off (or broken off in my nose) soon enough :-).
AnswerID: 286369

Reply By: Marclau - Friday, Feb 08, 2008 at 18:21

Friday, Feb 08, 2008 at 18:21
This is great feedback and I like the idea of making the antena if I can. I reckon I need approx 5-6 meters to run it to outside and then I need advice on parts I reckon..........so any help would be appreciated.

cheers
AnswerID: 286399

Reply By: Marclau - Friday, Feb 08, 2008 at 18:33

Friday, Feb 08, 2008 at 18:33
Also of noted interested (and I am a newbie at all this, this late in life)
at night time I can easily reach others who are anywhere between 10-20kms away using my handheld only from inside my study.......
AnswerID: 286405

Follow Up By: Mike Harding - Friday, Feb 08, 2008 at 18:58

Friday, Feb 08, 2008 at 18:58
Right Marclau - I'm going to try and snare you for Amateur Radio - never mind all this CB stuff - come and do some _real_ radio :)

To obtain an Amateur Radio licence was, for many years, pretty difficult - you needed lots of tough technical knowledge and the ability to send and receive Morse Code.

All gone - thank goodness!

We now have the "Foundation Licence" which will allow you to obtain significant radio capabilities with just a weekend's study. UHF CB will pale into insignificance when you realise you can obtain the capability to transmit on 2m (146MHz - a host of repeaters) and great local coverage plus the ability to use most HF frequencies and talk all across Australia and the world. I frequently chat to people in Europe, USA, Russia and dozens of other countries from some remote spot in the bush with my HF radio, battery and a bit of wire for an antenna.

Take a look here:

Foundation Licence 1

and here:

Foundation Licence 2

and let me know when you're on air and we'll have a chat :)

Mike Harding
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Reply By: Marclau - Friday, Feb 08, 2008 at 19:27

Friday, Feb 08, 2008 at 19:27
Thanks Mike...........I will certainly be looking into this but not right this minute.........
Unfortunately in and out of hospital with radiation treatment and the like........5 months down and still a little while to go........

As for the courses, a weekend is'nt to bad at all........:)

Any further details as to cost etc?
AnswerID: 286417

Follow Up By: Mike Harding - Friday, Feb 08, 2008 at 19:37

Friday, Feb 08, 2008 at 19:37
Very sorry to hear that Marclau - a good friend of mine is in a similar condition and she is doing very well - hang in there.... :)

The Amateur Radio clubs who run these courses keep costs to a minimum - I'm not sure of the exact numbers but $100 is probably in the ballpark for the course and exam and the ACA will charge you about $50 a year for holding an Amateur Radio licence.

Drop me an e-mail at"

if you would like more info.

Go well Marclau

Mike Harding
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Follow Up By: Mike Harding - Friday, Feb 08, 2008 at 19:39

Friday, Feb 08, 2008 at 19:39
mike_harding@fastmail.fm

don't ask me why Ex Oz filters it!?
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Reply By: Marclau - Friday, Feb 08, 2008 at 19:52

Friday, Feb 08, 2008 at 19:52
Thanks Mike for the warm and friendly welcome from yuo and the rest of the forums members.........

In fact, probably for the past 35 years I've had an interest in Ham and CB's but never got around to it.

Funny when things like health makes you quickly reassess life and then its all fast forward from there.

In the past fortnight, I've purchased a Degen DE1103 DIGITAL PLL AM FM LW SW SSB WORLD BAND RADIO RECEIVER and a DE31MS INDOOR ACTIVE LOOP ANTENNA FOR MEDIUM WAVE & SHORT WAVE and having lots of fun with that. Both recently purchased of eBay.

Add to that my new Uniden UH089SX CB and Uniden UH075 HH, which sits along side UH042 HH and a Bearcat 200 channel scanner.....
It's very quickly becoming very addictive and yes, I know my stuff is only amateurish, non the less I'm having heaps of fun staying up to early hours of the inght listening.

I'm down the Peninsula and unfortunately not local so if any forum members are on the air and I can reach you, call me up.

cheers
Marcel

Usually mates call me Dutchie, so if you hear me, say gidday...!!!!
AnswerID: 286421

Follow Up By: Mike Harding - Friday, Feb 08, 2008 at 19:58

Friday, Feb 08, 2008 at 19:58
Not sure where you are Marclau but if you mean the Mornington Peninsula in Vic there are a number of radio clubs around there who would be more than happy to assist - drop me an e-mail.

Mike Harding
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Reply By: Marclau - Friday, Feb 08, 2008 at 20:11

Friday, Feb 08, 2008 at 20:11
Thanks Mike,

Just shot you an email.

You are correct as well in that I'm down the Mornington Peninsula...albeit not too far down....Langwarrin to be exact.....

:)
AnswerID: 286426

Reply By: flyboy - Saturday, Feb 09, 2008 at 21:27

Saturday, Feb 09, 2008 at 21:27
Marclau,

I second what Mike has said, if you have an interest in radio and electronics, make the effort when you can and try and get your Amateur Licence. Leave the chicken band (CB) to talk to other members in your travel party and don't expect anything more than short range communications.

I started off on CB many years ago and that sparked my interest in radio, eventually going on to get my Amateur Ticket and then working in the Communications Industry.

As mike has said, it is a lot easier now to get your license than it used to be.

Good Luck!!
AnswerID: 286601

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