small crackle in UHF

Submitted: Thursday, Feb 17, 2005 at 17:35
ThreadID: 20540 Views:3346 Replies:13 FollowUps:18
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Hi All
I have installed my new GME 3400 UHF, but there is a very small crackle in it when driving. It is not present when just the engine is running, but when I am driving. I have hooked up the unit straight from the battery through a relay that is activated by the ignition be turned on. I have it earthed on a bolt inside the cabin on the firewall.
I just added the relay to try and see if that would make any difference, I first had it set up just hooked into the ignition circuit and noticed the crackle, so i ran the wire straight from the battery.
Any Ideas.

ta
Crazie
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Reply By: Patrolman Pat - Thursday, Feb 17, 2005 at 17:40

Thursday, Feb 17, 2005 at 17:40
If it's only there when driving it sound like it could be a loose connection.
Does it crackle when you rev the engine? Does it crackle through the speaker? Is it there when you transmit? or receive? or all the time?
AnswerID: 98849

Follow Up By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 17:45

Thursday, Feb 17, 2005 at 17:45
checked all the connection, not loose. It is only when driving along. Seems to be only there when recieving.

Could it be a bad earth??
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FollowupID: 357247

Follow Up By: Patrolman Pat - Thursday, Feb 17, 2005 at 17:52

Thursday, Feb 17, 2005 at 17:52
It can't harm to recheck the earth. try and get good contact to shiny metal. I'd also looka t the antenna, connections as well. If it receives OK stationery it sound like something could be vibrating and giving poor contact.
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FollowupID: 357248

Follow Up By: Bonz (Vic) - Thursday, Feb 17, 2005 at 17:53

Thursday, Feb 17, 2005 at 17:53
I as going to say that Pat, I ran mine back to the battery, prolly its the Jack crackle and pop!
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FollowupID: 357249

Follow Up By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 18:05

Thursday, Feb 17, 2005 at 18:05
thanks fruit loop..... lol
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FollowupID: 357255

Follow Up By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 18:42

Thursday, Feb 17, 2005 at 18:42
Earth to battery, still small crackle...
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FollowupID: 357266

Follow Up By: Glenn (VIC) - Friday, Feb 18, 2005 at 12:02

Friday, Feb 18, 2005 at 12:02
Hi Crazie,

Just check your soldering at both the the aerial end and the connection to the unit end. A bad connection there can cause annoying noises.

Cheers

Glenn
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FollowupID: 357356

Reply By: Member - Bradley- Thursday, Feb 17, 2005 at 17:52

Thursday, Feb 17, 2005 at 17:52
Try shifting the earth point, or return the earth to the batt. but more info please, ie does the crackle frequency rise and fall with engine revs while mobile? or rise with road speed? or is it constant.

You could try jiggling all the connectors on the coax while it is running to see if its a bad / loose connector.
AnswerID: 98852

Follow Up By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 18:01

Thursday, Feb 17, 2005 at 18:01
Hey Brad
I will try shifting the earth. It only crackles when moving, not rising and falling with acceleration, constant small crackle. Does not do it when sitting still and reving the engine. The coax seems to be ok, comes straight from the aerial to the unit, all tight.

ta mate
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FollowupID: 357253

Follow Up By: Member - Bradley- Thursday, Feb 17, 2005 at 18:09

Thursday, Feb 17, 2005 at 18:09
ok so its not a alt / spark issue, could be something silly like a slightly dry connection on one of the body /chassis / battery cables which is playing up due to the vibration and body movement while driving.
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FollowupID: 357256

Reply By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 18:28

Thursday, Feb 17, 2005 at 18:28
OK I have change the earth to the battery, still crackle on receiving. Could it me the movement of the aerial?? I have a 4.5db aerail on my bull bar, gme bracket, gme spring then the metal rod and then the aerial.?????
AnswerID: 98856

Follow Up By: BenSpoon - Thursday, Feb 17, 2005 at 21:39

Thursday, Feb 17, 2005 at 21:39
Where is your aerial placed on the roobar? Try and get it to the extreme side of the car.
I have installed a number of sub/amp sets, and have noticed that running cabling down the centre line of the car, or earthing off the centre of the car can cause interference when the drive train is spinning.
I moved the earths off the centre and fixed to the side of the vehicle and interference cut down significantly; its a similar situation with the cable runs if running over transmission tunnels etc.
Try and also make as few passes across the width of the car as possible.
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FollowupID: 357281

Follow Up By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 23:06

Thursday, Feb 17, 2005 at 23:06
The aerial is on the passenger side of the bar, I have the power and the earth crossing over the centre of the car once as the unit is mounted on the passenger side, the aerial goes straight from the passenger side.

thanks for your help

Crazie
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FollowupID: 357293

Reply By: DeanoNSW - Thursday, Feb 17, 2005 at 19:04

Thursday, Feb 17, 2005 at 19:04
Try earthing both the radio chassis and the antenna base. Just use the flex from some spare coax.

From there you can try getting a RF choke from Jaycar/Dick Smith electronics. This is placed around the positve lead.

If all this fails, try and isolate the source of the RF interference. I am not sure of what sort of vehicle your are running. Could it been an electric motor, perhaps the fan (either engine or heater/airconditionor).

Cheers
AnswerID: 98857

Follow Up By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 23:08

Thursday, Feb 17, 2005 at 23:08
I will try to earth the aerial base
cheers
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FollowupID: 357295

Reply By: Utemad - Thursday, Feb 17, 2005 at 19:08

Thursday, Feb 17, 2005 at 19:08
Does it taste like chocolate?

Try unplugging the antenna. If the noise is there with the antenna plugged in and gone with it unplugged then it is antenna related. If it is still there without the antenna then it is obviously not the antenna.

I used to get park plug noise through my speaker in my Tx4400. Tried all sorts of things to get rid of it but to no avail. After a while though I realised the noise was gone and it never came back. Never did find out what was wrong but I'm happy now.
AnswerID: 98858

Follow Up By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 23:09

Thursday, Feb 17, 2005 at 23:09
Just like a chocolcate milkshake lol...

I will try and see if it is the aerial or the power/earth supply

thank you
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FollowupID: 357296

Reply By: D-Jack - Thursday, Feb 17, 2005 at 22:12

Thursday, Feb 17, 2005 at 22:12
Crazie,

I got that too with my Uniden. Try driving out of the city - where there are no telegraph poles, underground or above ground electricity. It seems the telegraph wires and the sorts create this for me - that is why I was stationary no crackle, only when driving in city. Country a different matter. Try it you may be surprised. May be a way to eliminate the crackle in the city but I don't really care because don't use it in the city, only on trips.

Hope this helps

D-Jack
AnswerID: 98879

Follow Up By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 23:10

Thursday, Feb 17, 2005 at 23:10
Ta D-Jack
I will get out of town and give it a whirl
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FollowupID: 357297

Reply By: Eric Experience. - Thursday, Feb 17, 2005 at 22:38

Thursday, Feb 17, 2005 at 22:38
Crazie.
To find the sauce run your cb from a spare battery on the cabin floor, and then run a tempory coax from the bull bar over the top of the bonnet and through the passenger window, If you are running a seperate speaker from the main box make sure the wires to the speaker are twisted to cancell out any signals. Eric.
AnswerID: 98883

Follow Up By: Member - Crazie (VIC) - Thursday, Feb 17, 2005 at 23:11

Thursday, Feb 17, 2005 at 23:11
Thanks Eric

I will hook up a spare battery in the morning, then try a spare aerial
cheers
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FollowupID: 357298

Reply By: DukeAtty - Friday, Feb 18, 2005 at 07:51

Friday, Feb 18, 2005 at 07:51
Adam... I had the same hassles... I moved the antenna to the roof on the drivers side and the problem was fixed....
It only used to crackle when the car was in motion... Use to drive me batty...
There is also a simple rule with UHF... "the higher the antenna the better"....
AnswerID: 98925

Follow Up By: Member - Banjo (SA) - Friday, Feb 18, 2005 at 21:28

Friday, Feb 18, 2005 at 21:28
Indeed - I'm researching a the purchase of an UHF to replace the TX3000 - looking at the Icom 400 Pro - in all cases, dealers are telling me that getting the antenna up high is half the battle in gaining a good signal. Reckon I will get it mid roof (again) but with a fold down fitting (wil probably use an elevated feed jobbie, with 3db / 6db screw ons).
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FollowupID: 357402

Reply By: Member - Mozza (NSW) - Friday, Feb 18, 2005 at 08:29

Friday, Feb 18, 2005 at 08:29
the higher the better?... not neccesarily true dukeatty. i'd personally re-check the soldered connection of the coax to the input at the back of the unit.
AnswerID: 98927

Follow Up By: Member - Crazie (VIC) - Saturday, Feb 19, 2005 at 09:16

Saturday, Feb 19, 2005 at 09:16
Cheers Mozza
Just redone the soldering on the connection, hope this will fix it..
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FollowupID: 357422

Reply By: Member - Banjo (SA) - Friday, Feb 18, 2005 at 11:00

Friday, Feb 18, 2005 at 11:00
I get a bit of that in my Jack at times on HF radios - I put it down to a circuit running in the computer - have noticed that when all else is off, there is a current drain still running - I'm no techo, but the computer is digi in operation and so is the UHF radio ... might be something getting out - re HF (another story) - have found the Jack to be an interference factory.... all but given up on that issue. I do know that my TX3000 UHF hangs up on channel 35 when scanning because the Barrett HF remote head is too close ! So digi signals come out of that I guess. Whatever - I can only use bush logic !
AnswerID: 98948

Follow Up By: Member - Bradley- Friday, Feb 18, 2005 at 13:34

Friday, Feb 18, 2005 at 13:34
Interference with am and hf radio ? yep welcome to the world of the 3.0td jack. The prob is that the catterpillar computer in the engine bay runs with an alternating current signal internally, and causes heaps of interference. We used to have one guy bring his in for service, he had extra bonding leads on the bonnet, all antenna bases grounded, even had some nice fine copper mesh wrapped around the ecu and grounded to act as a farraday cage to try and stop it, but he still had some interference.
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FollowupID: 357366

Reply By: signman - Friday, Feb 18, 2005 at 15:00

Friday, Feb 18, 2005 at 15:00
G'day Crazie,
Was it you who wanted information on antenna separation??

On you current noise problem...have you got the mute/squelch set correctly??
If so..the symtoms appear to be antenna/ connection related.
Also, there has beenissues with the co-ax inside the earth tube- thats the tube the antenna whip screws onto.

Hope you can fix it
Signman
AnswerID: 98978

Follow Up By: Member - Crazie (VIC) - Saturday, Feb 19, 2005 at 09:21

Saturday, Feb 19, 2005 at 09:21
Hi signman
Yep it was me. I haven't pulled the aerial end appart that was already made up, so i might pull that apart and check it.
I hope i can fix it too lol...
thanks mate
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FollowupID: 357423

Reply By: muzzimbidgie - Friday, Feb 18, 2005 at 19:55

Friday, Feb 18, 2005 at 19:55
My UHF does this as well, only when the vehicle is in motion, and only when the radio is picking up a signal. To me it sounds different the faster the vehicle is traveling, and I put it down to interference from the ABS brake system, or something in the ECU that requires information on the vehicles speed.

I drive an auto 3.0 GU.

Cheers,

Muzz
AnswerID: 99014

Reply By: AdrianLR - Friday, Feb 18, 2005 at 21:38

Friday, Feb 18, 2005 at 21:38
A mate who's a Ham fanatic bought an Audi A6 diesel so that there wasn't any ignition noise but found that there was a whine on particular frequencies. Started pulling fuses and found that it was the self-levelling air suspension. Perhaps you could follow a similar route - at least if you can isolate the circuit/sensor that causes the noise then you might be able to re-route cables to get as far away as possible.

Good luck

Adrian
AnswerID: 99024

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