UHF Range??

[DazzaMTD]

I've just purchased a GME TX 4400 with a GME Antennea (4.5dB), just wondering what the estimated range should be for this combo. Tested it with a mate on the hwy, and it picked up fine within 40-50m but any longer and the radio would start to break up. I intalled it myself, and am just wondering if the Antennea cord is properly connected to the socket which attaches it to UHF unit??? Or there is some setting i need to change??
I really have NFI

It could be my dodgy souldering job i don't know but it should have a bigger range than 50m surely. I may have to pull it out and start again, i've got plenty of cable to play with.

Any help would be much appreciated.

 

[millsy]

I have been having simillar problems. Have blown up the output amp twice now. I think I might not have a good earth for the bottom of my antenna, so that's where I will be probably setting up a wire right back to my negative post on the battery, rather than relying on the sharp claw that is supposed to bite into the metal of the antenna mount.

You might have an earth problem too.

I am also going to check that I do not have a short between the centre (signal) wire of the antenna, and the outer (earth) braiding. A multimeter should check this out easily enough - just set it to the resistance ( or ohm-meter ) setting. It should read infinite resistance between the inner and the outer, when it is all hooked up, but the antenna not plugged into the radio.

Good luck. It's really frustrating, these antenna problems.

 

[Walkabout]

G'day Dazza , the radio should have an average range between 12-18 klm depending on where you are, steep hilly area's will reduce it a fair bit more.
Two things to watch out for is bad earth connection be it on the eletrical wiring or the antenna mount..
Make sure eletrical cables have a good secure earth and solder the connectors not just crimp them.
Depending on if you bought a ground independant antenna or not and how you mounted it (IE: bullbar/bracket supported from under bonnet etc) you may try running a short cable attached onto either mount bracket system to a good earth point close by.
And yes maybe re-do the antenna connector at the back of the radio- take your time to do a smick job ( instructions can be found in a similar thread)
Lastly if you feel it's not transmitting properly stop using it as if any of these things mentioned has a problem it can damage your new unit.

 

[gregu78]

Do you mean your transmit signal was breaking up on your mates radio, or his signal breaking up on yours? Maybe his setup is nqr.
Being 4.5db gain will mean less distance, but should still easily reach 15km's on flat highway.

Another thing apart from what has been mentioned, make sure you don't run the -ve of the radio to the vehicle's earth. This can easily blow the power transistor. I always run the power cables directly to the battery (fused of course)

Best way to test your setup is with a SWR meter, but you probably don't want to fork out cash to buy one, see if someone will lend you one.

Failing that, give Timeplus a call and ask if they'll test your setup. They're in Brunswick.
CB Radios Australia. Online ordering of CB Radios Australia.

 

[DazzaMTD]

Thanks guys,
just wondering how do get good earth on antenna??
and wat is an swr meter??

p.s his signal was breaking up on mine, so i think mines the problem

 

[millsy]

The way I undestand it is that reception is not a big problem. The internal amplification for the recieved signals is so good that even a faulty antenna on your own vehicle does not stop you from hearing other people talk.

But if you have a faulty antenna set up it really affects how well you are 'getting out' as they say. That's the first thing people say when you ask for a radio check. If they can receive you loud and clear they say that you are 'getting out' well.

When I was having my problems in the Big Desert a few weeks ago, luckily we both had two radios - the UHF and the old CB. So when my UHF blew up, I transmitted to my mate on the CB, and he transmitted back to me on UHF, because my UHF was still receiving quite well. It just could not transmit.

In the end the earth on my CB broke off ( a blob of solder on the large claw had broken away from the claw - the claw that is supposed to give an earth to the radio by biting through the paint on the antenna mount. That's why in future I will run a wire right back to the negative post on the battery for an earth).
So we had to make do with me transmitting on the UHF only when my mate was within about 10 metres from me! Any further and he just got a garbled noise.

Welcome to the world of radio. Hope you have more luck than I am. I remember years ago when I used to run a CB I never had any of these problems. Luckily my radio is still under warranty, but they might 'pull the plug' on me if I keep presenting them with burnt out power amps!

 

[gregu78]

Did he say if your transmission was ok? If so, sounds like it's a problem with his rig. If there were no hills between your house and mine, we would be able to communicate crystal clear.

Post the model number of your antenna and we'll determine if it's ground dependent or not. If it is ground dependent, the best ( and most impractical ) place to mount it is the centre of the vehicle's roof!

SWR stands for standing wave ratio. What happens is the RF energy is transmitted via the coaxial cable to the antenna. The antenna is best described as a leaky transmission line that radiates the RF into space. If the antenna is not the correct length for the frequency of use, then some of this RF energy will be returned down the transmission line to the radio. When the antenna is of the correct length, it is said to be resonant.
But I don't think that's your problem

 

[havok011101]

You didn't have squelch turned all the way up or something (or down, but you know what I mean).

Just a thought....

 

[Grey Ghost]

I think Havoc may have it there, turn the sqlech control to minimum or, if its a push button job, push the button so that you can hear the background static and try again. And get him to check his setup out...

 

[warfer]

I would change the 4.5db to a 6.5db..Its better on average (Hilly and Flat)..If your mostly in a flat only go 9.5db


Goodluck with your issue..

 

[Yota]

UHF Range

If your radio is only txing 50 metres I hope I am wrong but you may have blown a power amplifier I had a Uniden that was like that, it was the antenna that caused the overload through high SWR. I fixed the antenna then found the output amplifier had blown, it was cheaper to get another second hand radio. Most store bought antennas might say their swr is minimum and some even advertise less than 1.5:1 across the entire band but relatively few achieve anything like that I had Benelec and GME 4.5 metre base antennas and these were fairly typical of mass produced antenna's giving about 1.7:1 for the Benelec while the GME was around 1.6:1 in the middle of the band and close on 2:1 at the upper and lower limits, on dissassembling both antenna and minor trimming and the use of an MFJ antenna analyser we were able to get the middle of the band down to 1.2:1 and the edges down to 1.35. I have struck mobile antenna's that were far worse than this. Some radio's will tolerate higher swr than others will, Unidens like swr to be lower than 1.5

 

[warfer]

Some antenna's hav a rubber grommet (Cap) on the end of them,If you damage it or loose the rubber when it rains the water can get down in there and blow the radio !

 

[DazzaMTD]

Squelch is fine, i've played around with it a bit and get the same result.

Your scaring me Yota i hope i haven't blown me unit!!

How do i get good earth on antenna????

The model of my antenna is
GME AE4018K1 UHF Antenna - Heavy Duty Elevated Feed Base, Barrel Spring and Fibreglass Colinear c/w 4.5 metres low loss foam Coaxial cable and PL259

 

[rodw]

Dazza, I think something is not right. I have the same antenna (well 2 of them) and have no problems with them and get the range that others are quoting. When I purchased one, I was told to check the antenna with a multimeter. There should be no continuity between the centre pin and the outside of the plug and there should be continuity between the centre pin and where the antenna screws in. (You might need to use a long wire with your multi meter to test this). You shouild also have continiuity between the antenna spring and the outside of the plug.

Here are some pics I took of how I prepared the connector that came with the antenna:

You have to screw the plug onto the cable and solder the tip. Here is what mine looked like before soldering the tip up:

I have been told you can blow up a UHF if you attempt to transmit without an antenna connected.

So I would sort out the antenna as I have discussed and if it still does not work, I would be going back to sort out a warranty claim on the UHF. But if your antenna is not done right you will probably not be able to get warranty.

 

[DazzaMTD]

Where can i get a multimeter and wat do i do with the outer wirering that you have pealed bac in image 1

 

[gregu78]

You can get a $10 multimeter from Jaycar in Thomastown, cat number QM1500

With the outer braid pushed back like that, you twist the connector onto it. The thread inside the connector will hold it on once done.

 

[Yota]

UHF Connectors

Those connectors that screw on over the outer braid, mostly marketed by tricky Dickies and Jaycar are crap, eventually you will see a poor electrical connection to the braid. A far better proposition is the clamp on or crimp on types. These screw on ones are never used in commercial installations and are just designed to be an easy install but reliability is an issue with them. If these connectors were so good they would be used in commercial and amateur radio circles which they are not.

 

[rodw]

Where can i get a multimeter and wat do i do with the outer wirering that you have pealed bac in image 1

It does not matter if there is a bit of braid sticking out round the collar once you screw it on, just trim it off carefully to make it look neat.

Those connectors that screw on over the outer braid, mostly marketed by tricky Dickies and Jaycar are crap, eventually you will see a poor electrical connection to the braid. A far better proposition is the clamp on or crimp on types. These screw on ones are never used in commercial installations and are just designed to be an easy install but reliability is an issue with them. If these connectors were so good they would be used in commercial and amateur radio circles which they are not.

You are right, the crimp on ones are better but the antenna Dazza bought came with a screw on one for free. I've used a few of the GME ones like the pics above and never had a problem and you don't have to buy a crimp on tool. I screw then on as tight as I can so I can't turn them any more. Dickies sell a cheap crimp tool but from what I know about crimping tools, the cheap tools can give you a crap connection anyway.

 

[JAFO]

Hi guy’s,

I run a Dual Band Amateur Radio Set that incorporates the 5watts UHF CB Channels. My Antenna’s (Mobile Phone, Scanner & Amateur Radio) are mounted on a Rhino Sports Bar which has plastic mounting ends and rubber protective pads, so stuff all earth connection between the Sports bar and vehicle roof or cutter to earth out the Sports Bar.

As I am able to put out a lot more power then 5watts (50watts on VHF and 35watts on UHF), I use a Copper Earth Strap from my “Radio Mounting Bracket” to a good earth connection inside the car, this being one of the Rear Car Seat Mounting bolts. This provides a good Earth Connection for the Radio Unit itself.

Even thou I have no earth contact with the Rhino Sports Bar, the coax still provide’s a good earth connection to my Antenna. I am still able to key into Amateur UHF Repeaters some 60Klm’s away (line of sight) on 10watts with a 5db antenna and have had no issues in the past 5 years with the two radios that I have operated on this setup.

So in short, ensure the radio unit itself has a good earth connection at its mounting point and like “millsy” has stated, check the resistance of your Coax Cable to ensure it is not bad, it should have a Resistance of ~50ohm’s.

Antenna mounting position also plays a big part. Antenna’s mounted on a Bull Bar sends most of your Signal back over the Vehicle’s Roof in a Rear wards direction, but you still should get out 2 or 3 Klm’s to the front of the vehicle on flat ground.

 

[DazzaMTD]

yes I've got it working
Thanks for those images rodw they were very helpful, all i needed to do was re-do the soldering job on the plug

Works a treat now, picking up signals from everywhere.

I love listening to truckies talking to each other it great, thus i don't listen to music anymore, i just leave it on scan mode for my entertainment!!!