Just some UHF Questions

Submitted: Saturday, Feb 28, 2004 at 19:51
ThreadID: 10883 Views:1977 Replies:9 FollowUps:14
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Hello all.

Well I have now purchased my new handheld UHF radio from a store in town. It is the 5 watt Uniden Uh052XR. It was performing great until I started to listen the first night. What happened was I was listening to on the channel 2 Gunalda repeater, and I noticed that I was getting very strong disorted signals coming from no where. So I decided to change to a different channel, but I noticed that no matter what channel I changed to, I could still here it. After about 5min or so I finally realised what the problem was, but I still can't figure out how to fix it. I noticed that every time a strong signal from this area was coming through, it would expose the signal on every channel except very disorted with all white noise, the squelch doesn't affect it either. What could this problem be? It's just frustrating because if I want to listen to something, if somebody local with a strong signal is talking on a different channel, I can hear that signal with white noise louder than what I can hear what I want to hear.

Also, just a question about "conditions". I've noticed that a lot of people use the word "conditions" on the radio, such as "you can pick up the channel 6 repeater in the right "conditions". What exactly are the "right" conditions?

And now for the last question. What is the MAXIMUM amount of distance you can hear people talking through on the same channel eg 2 repeater but being picked up through another repeater in another area? I always here people on the Gunalda repeater say that you can pick up the channel 2 Brisbane repeater through the Gunalda one, and I believe this. But can you pick up more than just 2 repeaters interacting with each other or over a further distance than 200km?
I know this is a long post, but I'm just really curious about all of this stuff on UHF.

Thanks

Adam :)
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Reply By: Wayne (NSW) - Saturday, Feb 28, 2004 at 20:39

Saturday, Feb 28, 2004 at 20:39
Adam,

You fixed the problem by turning the "Duplex" on.
When you are on a repeater channel one through to eight the unit allows you to transmit on a different frequency to that which it recives. The Duplex fuction operates only on channels 1-8. When Duplex is selected on one of these channels the unit recives on that channel but actually transmits 30 channels higher.

E.g. Channel selected 2
Receive channel 2
Transmit channel 32

When you operate through a repeater it automatically re-transmit your signal over a wider area.

There is a repeater near home at the base of the mountians. The repeater channel is 3. Through this repeater I can talk to a mate 30klm away.

The right conditions are line of sight. If you can look in the direction of where you want to transmit and there are no large objects like buildings.mountians the signal will travelle in a straight line. It does not like going over large objects.

In hilly terrain 1- 1.5 klm in the dessert 10klm.

There could be two repeaters interacting which each other but you will only pick up the repeater that has the strongest signal on your set.

Repeaters put out a signal that sounds computer generated. That lets you know you are in range. Always Out'N About
AnswerID: 48562

Follow Up By: Mad Dog Morgan (Geelong) - Saturday, Feb 28, 2004 at 21:52

Saturday, Feb 28, 2004 at 21:52
Wayne, with my experience with narrow band FM the FM capture theory
aint worth diddly squat and you end with with both signals just producing a horrible mess. BEAM ME UP SCOTTY


Hooroo
Ray
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FollowupID: 310393

Reply By: Dave from Fraser Coast 4WD Club - Saturday, Feb 28, 2004 at 20:42

Saturday, Feb 28, 2004 at 20:42
Sorry to burst your bubble but the "White noise" is because you bought a Uniden it is either playing up or just poor quality. Sorry. Take it back and get them to have it repaired IMHO.

You can not access a 2nd repeater thru a 1st. If you were on elevated ground halfway between Gympie and Brisvegas you might be able to hear both, (but probably wouldn't be able to use either).

The fact of the matter is that for a sigan to be picked up and retransmitted by a repeater the original broadcast has to made on the repeaters "listening" channel. (in the case of Gunalda, that is ch32), that signal is then boosted and simultaneously retransmitted on ch2.

For a signal to be resent thru a second repeater it would need to have been transmitted on the second repeaters listening channel, therefore making it impossible for the original transmission to have taken place in the first instance.

I'm not suggesting that retransmittal is impossible but it would involve purpose built systems, ( I think that Marine VHF does this in certain remote locations)

Hope that this helps.
AnswerID: 48563

Follow Up By: AndrewX - Saturday, Feb 28, 2004 at 21:18

Saturday, Feb 28, 2004 at 21:18
Yes DAve exactly what I was thinking regarding re transmission. A channel2 repeater could not hear another channel 2 repeater as it receives Channel 32 and transmits channel2. Does the original poster realise that when he transmits on channel 2 duplex he is in fact transmitting on channel32 and his signal is picked up by a repeater which in turn sends it out as a Ch2 signal therefore it won't be received by another repeater. I have achieved distances of over 100km through a repeater in a very elevated area (I think it was MAnsfield) The white noise problem sounds like a fault to me. The Uniden sets are not the same quality as GME sets but they aren't that bad normally.
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FollowupID: 310389

Reply By: Bob Y. - Qld - Saturday, Feb 28, 2004 at 21:46

Saturday, Feb 28, 2004 at 21:46
Adam,

Would agree with the others, that it might be a Uniden problem. The GME's are much better, even if they are a bit dearer. Better audio too.

"Right Conditions" for long distance can occur after widespread rain events, as in Qld January, '04. The atmoshere is much clearer, and transmission distances can be up to many hundred of clicks. Even 1,000's if you are using a Yagi antenna set-up.

Also "ducting" occurs when a cool layer of air is trapped between 2 warmer layers, and signals get "ducted" along these layers.

2 repeaters can't interact together, but if someone has an efficient UHF radio/antenna, then they could access both repeaters at once, as long as they were all on a common channel. We can pick other repeaters, over 200 kms away, in the "right conditions"

Hooroo...

AnswerID: 48570

Reply By: Mad Dog Morgan (Geelong) - Saturday, Feb 28, 2004 at 21:49

Saturday, Feb 28, 2004 at 21:49
You have a very severe case of what is commonly refered to as front end overload.
All radios can suffer this to various degrees especially handhelds which are made with a very sensitive receiver. Some radios are better than others depending on the design but radios with wide band receive suffer more. Do you have a cb'er or ham radio operator living close or maybe a commercial radio installation or maybe it's a crook radio, the unidens aren't held in high regard for reasons I don't know. BEAM ME UP SCOTTY


Hooroo
Ray
AnswerID: 48572

Reply By: Empfys - Saturday, Feb 28, 2004 at 21:56

Saturday, Feb 28, 2004 at 21:56
Thanks for all the replies guys. I've known all the stuff about duplex such as having it on, transmitting on 2 really transmits it on 32, but thanks for filling me in on the repeater stuff and the problem. I purchased the Uniden model because it was a special for when the store first got it in. It came with the cord to the cigarette lighter, desktop charger and the original AC Adapter for $379. I know the GME Electrephones are better quality, but I didn't think it was so much better as you guys know it is.
Thanks for the help.

Adam :)
AnswerID: 48577

Reply By: Truckster (Vic) - Saturday, Feb 28, 2004 at 23:28

Saturday, Feb 28, 2004 at 23:28
Take it back, get it replaced, if its still fubar, get your $$ back..
AnswerID: 48601

Reply By: Member - Ruth D (QLD) - Sunday, Feb 29, 2004 at 15:13

Sunday, Feb 29, 2004 at 15:13
I have three (3) Uniden hand-held radios which my gate-keepers/security use at race-time and if taking people out to the SD and they don't have installed ones. Now I have found them excellent - can even talk to the property 30 klms from town. Only problem I have found is strange distortion sometimes, also runs through every channel (no not when on scan) and distorts every channel. So had long conversations with Uniden in Sydney. This model has very fine receiver but does not like being near certain objects - e.g. the expresso machine, the Eftpos machine. Telephones are alright. This may not be the answer to the original problem but when the distortion happens check what electronic thing is nearby. Might help. With regard to repeaters - in our Shire Channel 8 is linked to other Channel 8 repeaters which now allows us to have almost Shire coverage. On a cloudy day we can hear almost up to Boulia (400 klms away). The linked repeaters were for safety so that when we are travelling (even the next town is 200 klms away) we don't have so many blackspots - because not everyone has satellite phones (yet). Sorry, not very scientific.These are Diamantina Barra (Yellowbelly)
GO HARD OR GO HOME
AnswerID: 48652

Follow Up By: Dave from Fraser Coast 4WD Club - Sunday, Feb 29, 2004 at 15:31

Sunday, Feb 29, 2004 at 15:31
I had heard of linked repeaters out bush, but can't figure out how they would work. If you know someone in the know out there I'd love to satisfy my curiosity.

On the uniden thing, everyone who owns them is happy with them, until they use a GME or ICOM.
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FollowupID: 310458

Follow Up By: Mad Dog Morgan (Geelong) - Sunday, Feb 29, 2004 at 17:35

Sunday, Feb 29, 2004 at 17:35
Linking is acheived by using another frequency either simplex or full duplex with yagis pointing at each other. Gee wizz, I can see a problem with linked repeaters on the same freq where the coverage area overlaps, the two transmitters would have to be on the EXACT same freq and in phase to avoid a horrible mess. I dont know how to do this without having both transmitters fed by the same oscillator and modulator. Linked repeaters are common on ham radio but they are on different freqs. BEAM ME UP SCOTTY


Hooroo
Ray
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FollowupID: 310467

Follow Up By: Member - Ruth D (QLD) - Sunday, Feb 29, 2004 at 17:37

Sunday, Feb 29, 2004 at 17:37
I will ask the guys about this tomorrow - give my brain something to think about - I just can't remember exactly how it works - but I'm a girl and that's the reason! One of the good things about this Forum is that I can learn so many things without having to let anyone know how dumb I am (usually). Let you know what I find out.These are Diamantina Barra (Yellowbelly)
GO HARD OR GO HOME
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FollowupID: 310469

Follow Up By: Dave from Fraser Coast 4WD Club - Sunday, Feb 29, 2004 at 17:40

Sunday, Feb 29, 2004 at 17:40
I can see how it would be done on different freq. (this is how marine ones work I am told) but the same freq. one has me baffled. I can think of a way it might work with a directional aerial.
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FollowupID: 310470

Follow Up By: Mad Dog Morgan (Geelong) - Sunday, Feb 29, 2004 at 18:00

Sunday, Feb 29, 2004 at 18:00
Dave, the input of repeater A feeds two transmitters, the user output freq and a freq that is linked to repeater B which is output to repeater B user freq. Repeaters controllers have provision for linking. BEAM ME UP SCOTTY


Hooroo
Ray
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FollowupID: 310473

Follow Up By: Dave from Fraser Coast 4WD Club - Sunday, Feb 29, 2004 at 18:05

Sunday, Feb 29, 2004 at 18:05
so does the repeater then resend on the same input channel eg 2/32 to this other linked repeater? or do they utilise a second 'listening channel' just for linking? i could see how that would work.
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FollowupID: 310474

Follow Up By: Mad Dog Morgan (Geelong) - Sunday, Feb 29, 2004 at 18:13

Sunday, Feb 29, 2004 at 18:13
Sorry Dave I'm not very good at explaining things. Yes different linking freqs are used.
It's damn amazing what can be done with linking these days. Numerous ham radio repeaters around the globe are linked via the internet. I can sit here using a program called echolink and trigger 70cm and 2m repeaters in many countries, USA, Europe, Asia. BEAM ME UP SCOTTY


Hooroo
Ray
0
FollowupID: 310475

Follow Up By: Bob Y. - Qld - Sunday, Feb 29, 2004 at 21:53

Sunday, Feb 29, 2004 at 21:53
Reckon Ruth has a good handle on these "blokey" UHF's. In Diamantina Shire(Birdsville), there are 2 Ch. 8 repeaters, as Ruth said, but recall that there is at least one more repeater, on a different channel. Just checked the UHF repeater list, but can only find the 2 Ch. 8 repeaters.

The Ch.8 repeaters are probably linked through this other repeater/s, which may simplify the linking channels to some degree.
The Boulia shire uses about 3 different channels, in their repeaters, and Diamantina shire could well do this too.

We have "range extender" linked to our repeater, it uses a simplex radio, plus a radio set to the repeater channel. Gives almost 100% coverage, for half the cost of 2nd repeater, around the station. Uses a base type antenna, plus a Yagi to access the repeater.

Hooroo...
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FollowupID: 310488

Follow Up By: Member - Ruth D (QLD) - Monday, Mar 01, 2004 at 12:44

Monday, Mar 01, 2004 at 12:44
Righto here we go. Diamantina Shire owns 8 repeaters and Kidman Stations own 3 and these are all linked. They go like this - Ch 1 is Carcoory, 2 Glengyle, 3 Durrie, 4 Can't remember, 5 Birdsville, 6 Monkira, 7 Bedourie, 8 Betoota, 9,10 and 11 - can't rememebr. Although they are different channels they are linked (it is a very complex linking that the Shire has) to enable us to utilise the repeaters throughout the whole of this, the second largest shire in Queensland, for exactly the reasons I gave yesterday. This type of linking is not uncommon and happens all over Australia - but in different formats. For in depth and boy talk explanations you could contact Norman at Mt Gambier Electronics on (08) 87232122 - they look after the Shire repeaters (for the big things) and we have a guy in Bedourie who does the regular maintenance. Our repeater system is not working properly at the moment and they are about to trial 10 year batteries. It is also very expensive system. Norman was very kind to me and gave me a simple version. Hope this helps.These are Diamantina Barra (Yellowbelly)
GO HARD OR GO HOME
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FollowupID: 310537

Follow Up By: Mad Dog Morgan (Geelong) - Tuesday, Mar 02, 2004 at 14:05

Tuesday, Mar 02, 2004 at 14:05
Thanks Ruth, are you sure that these are UHF CB repeaters. It appears to me they must be private repeaters on freqs different to UHF CB. Why do I think this, CB Repeater licensing prohibts the linking of repeaters. BEAM ME UP SCOTTY


Hooroo
Ray
0
FollowupID: 310690

Follow Up By: Member - Ruth D (QLD) - Tuesday, Mar 02, 2004 at 14:57

Tuesday, Mar 02, 2004 at 14:57
Gee Ray - I'm just a girl. They are UHF repeaters - 10 owned by Diamantina Shire and 3 by Kidman. As for the scientific babble - me no understand. I do find it very interesting though and am sorting my way now through the GPS stuff to put one in the new toyota Ute and 5.3 metre boat - I can mount it, use it but not sure that I totally understand some things (that's life). Try Mt Gambier Electronics - Norman was helpful to me and they are the guys who did all the work, and will be coming up end March to do some more, including trialling the 10 year batteries. These are Diamantina Barra (Yellowbelly)
GO HARD OR GO HOME
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FollowupID: 310699

Reply By: Member - Jeff M (WA) - Tuesday, Mar 02, 2004 at 14:08

Tuesday, Mar 02, 2004 at 14:08
I have the same UHF handheld, bought it second hand from a pawn shop. Works great, get's out very very well, I do find I get the same distoration too. I used to get it badly where I used to live, I would actually pickup a courier channel or somthing similar across all the channels, it was frustrating, since I have moved I know longer have the problem. I get it occasionally when I get close to Perth if I take it in the car, the GME TX3000 used to get some as well but since I changed arials on that I don't get it anymore. That is a different kind of interference though, sounds like some kind of telemtry, maybe the trains or somthing.Should probally go do some work instead of playing on this forum!
AnswerID: 48878

Follow Up By: Member - Ruth D (QLD) - Tuesday, Mar 02, 2004 at 14:59

Tuesday, Mar 02, 2004 at 14:59
Jeff, if I have the handheld on for some reason near the car (both vehicles have GME TX3000 installed) then the distortion is really bad. Uniden explained that the pick-up (receiver) was really good, but a bit too good.These are Diamantina Barra (Yellowbelly)
GO HARD OR GO HOME
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FollowupID: 310701

Reply By: Empfys - Thursday, Mar 04, 2004 at 15:20

Thursday, Mar 04, 2004 at 15:20
Hey again all.

Well thank for once again for all your responses. Also, I just noticed, it's only when people are talking on channel 9. If the locals are back up on 14 talking, it doesn't effect the radio whatsoever, so yeah, some weird stuff there. Anyway thank you for your help. :)

Adam :)
AnswerID: 49136

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