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Discussion Starter #1
ok so i installed my new CB that i was given for x-mas and when the truck is turned off i get great clairity (reception). but when i start it up and amm driving, i have to turn the squelch more to the max side because of what sounds like engine noise coming through. Is my antenna just picking this up or what? andy help would be great.
 

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yeah.... you should really filter your power before it goes into the radio. where did you pull your power from anyways?
 

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pull power directly from the battery. you must have great grounds as well, thsoe are jsut as important. has your antenna been tuned for your vehicle?

you might think of adding a noise suppresor
 

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X2 on the filter and ground. A filter will help some. You can get a in-line filter from Radio Shack for around $10. Most importantly however is to make sure you are grounded to the body of the truck. I had tons of problems with my cb for a long time. I finally made a REALLY GOOD ground to the body and not only did the noise go away, but my reception was better. I never knew how important the ground was for CB's until I did a ton of research.
 

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jimmyray said:
ok so i installed my new CB that i was given for x-mas and when the truck is turned off i get great clairity (reception). but when i start it up and amm driving, i have to turn the squelch more to the max side because of what sounds like engine noise coming through. Is my antenna just picking this up or what? andy help would be great.
I agree with Jimbo.....extend the CB wires and run both directly to the battery....but first remove the battery cables and clean them with a wire brush to ensure superior contact......you might be amazed how quiet it will be after that.
 

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If you use a low pass filter or band pass filter as they are called in amature radio terms, you will loose about 1 S-unit on your transmit side of your transciever.. Your problem, although you didn't mention how you gave your radio power, sounds like your running off a cig adapter which will give ya alot of engine noise.. I will agree with others on running direct to battery, I would also ground your radio inside the cab also, make sure your antenna ground is clean.. use an ohm meter and check resistance.. good luck..
 

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Discussion Starter #7
ok so i am grounded to the battery and draw my power from it also. I have an in line filter. antenna is tuned. How do i ground the thing inside the cab? take it off the battery and just go inside the cab somewere?
 

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Discussion Starter #8
i have a basic 40ch cobra. a magnet mount metal ant.
 

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a magnet mount antenna doenst help, they dont allow the antenna to properly ground, they are called a no ground plane antenna, sure they will work, but they are not properly grounded like a solid mount antenna. also make sure the body is grounded well to the frame, this may actually includ some ground straps, yes the frame is bolted to teh body through body mounts, but this isnt enough
 

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jimmyray said:
ok so i am grounded to the battery and draw my power from it also. I have an in line filter. antenna is tuned. How do i ground the thing inside the cab? take it off the battery and just go inside the cab somewere?
If your still getting motor noise, your ground wire is picking up EMF inside your engine compartment and that maybe fixable with better plug wires or maybe not , you could run the shortest possible ground from your radio power plug take the black wire and run it to the chassis under the dash.

I always ground my radio seperately also.. just run a wire from one of the screws on the back of the radio, there should be a single one in the center by itself, my Uniden Grant XL and Cobra 148GTL have those xtra ground screws.

a mag mount will work fine as long as your not running power.. not that I am advocating a linear amplifier in the 11 meter band aka CB.. if your running a few hundred xtra watts it will have a negative effect on your ground plane!!!
 

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Discussion Starter #11
so in short ground the physical radio to somthing, not just the gound wire coming outa the back. and maybe find a better ground then the battery for the actual ground wire. do u think that getting a fixed antenna and grounding it will help also?
 

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jimmyray said:
so in short ground the physical radio to somthing, not just the gound wire coming outa the back. and maybe find a better ground then the battery for the actual ground wire. do u think that getting a fixed antenna and grounding it will help also?
It all depends on what your using it for! If your just talking to your buddies truck to truck, you should be fine with a mag mount.. I am also a FCC licensed Amature Radio operator, so I tend to use the largest amount of overkill I can.. it all depends on what you want to achieve..

did your motor noise decrease to a tolerable level??? If so, take out the filter and see if it makes a difference or not!! If not, loose it, Those filters take away some of your transmit signal and your recieve also.. Every extra connector you add to your feed line will take away 2 db. from your transmit and rx. also keep your coax as far away from your stereo speaker wire...
 

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If your still having problems, check your feed line (coax) and look for any nic's in the shielding.. it may have a loose solder joint at the base of the antenna you cannot see also... I don't know what kind of antenna your using, but the cheaper ones can be a problem...
 

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jimmyray said:
when i start it up and am driving, i have to turn the squelch more to the max side because of what sounds like engine noise coming through.
i hate to tell you this but it's very likely ignition noise, and most likely from the ignitor and the 6 COP assemblies. the only solution is a pile of clamp on ferrites. see the attached pics for a head start. the mass amount of ferrites i employed dropped my ignition noise level by at least 30-40dB (that's a metric crapload, btw). but first read on...

jimmyray said:
Is my antenna just picking this up or what?
start the truck.
turn squelch to about midway.
disconnect the antenna from the back of the radio.
did the amount of noise on the radio decrease?
if so, the antenna is picking up the noise and you will have to shield/ferrite the ignition system and/or the alternator system.
if not, the noise is coming in through the DC power and you will have to filter the DC power as close to the radio as possible. note that it does no good to put the filter in the engine compartment -- all of the wiring "downstream" of the filter is just picking up more noise.

jim aka the wrooster
and aka N2MPT







 

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Wow, Jim...

I didn't have to do ANY of that to my truck.

Do you guys have noise blankers and automatic noise limiters in your radios?

I have an RCI 2950 and a super cheapo Cobra 19. I swap them out depending on what I'm doing at the moment. I've never had a noise issue at all.

That's wierd.
 

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jimbo74 said:
a magnet mount antenna doenst help, they dont allow the antenna to properly ground, they are called a no ground plane antenna, sure they will work, but they are not properly grounded like a solid mount antenna. also make sure the body is grounded well to the frame, this may actually includ some ground straps, yes the frame is bolted to teh body through body mounts, but this isnt enough
Not true.

You are confusing an RF ground and a DC ground. They are NOT the same thing. (Clue: You cannot measure RF with your ohm meter)

A magnet mount does in fact use the body of the truck for a ground plane.

A magnet mount is capable of producing a perfectly workable ground right through the paint and can be tuned to minimal SWR because THE MAGNETIC FIELD OF THE MAGNETS IS CONDUCTIVE TO RF.

A No ground plane antenna does not require a car body to work. That's why they call it a no-ground plane antenna and it can be installed on a fiberglass car or whatever.

A magnet mount antenna cannot work on a fiberglass car. You could duct tape it on there, but it will not tune because it needs the ground plane provided by the metal truck body.
 

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Rock-N-Ruin said:
It all depends on what your using it for! If your just talking to your buddies truck to truck, you should be fine with a mag mount.. I am also a FCC licensed Amature Radio operator, so I tend to use the largest amount of overkill I can.. it all depends on what you want to achieve..

QUOTE]

That's not fair at all. I use a Wilson 1000 mag mount for all my 10/11 meter radio needs in my truck. (I'm KC5WDP)



On the trail, it's a little too tall and it smacks every tree I get close to.

It's been knocked off a time or two, but it works well for talking truck to truck.

At other times, I remove the little Cobra and install my RCI and the amplifier.

On 10m sideband, I have made mobile contacts world wide. I have QSO'ed with people in Russia, Germany, Japan, England, Norway,Hawaii, and more other places than I can't remember right now.

I do all this with the wilson.

Don't discount magnetic antennas. Properly installed and tuned, they can "Drop That Mall" with the best of them!
 

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I'm running a perm. roof mount wilson 1000 and a cheapie cobra 40chan.... It's been wonderful, I get noise from my radio though. I'm powered through switched power behind the dash, and grounded to the dash frame.... When my stereo is on I have to squelch up, if it's loud, you can see the meter on the cb bouncing to the music.... WHen I take the antenna off the roof, the signal shows ABSOLUTE zero even with the stereo blaring.... It doesnt bother me, and my range is more than sufficiant so I'm not messing with it.
 

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Keep you ground wire as short as possible... Another trick i learned from installing CB's is to temporarily wire the cb Don,t hide any of your wires. Test the Cb if all is good permanently wire is with the wires in the same location... If you get lots of static then try rerouting your wires until you find a good location... I found sometimes just moving the antenna wire or the power wire to the other side of the cab clears everything up with out having to buy extra filters and such... My Cb was picking up noises from the fuel pump... moved the wires to teh other side of the cab and everything was good...
 

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fast frank said:
Not true.

You are confusing an RF ground and a DC ground. They are NOT the same thing. (Clue: You cannot measure RF with your ohm meter)

A magnet mount does in fact use the body of the truck for a ground plane.

A magnet mount is capable of producing a perfectly workable ground right through the paint and can be tuned to minimal SWR because THE MAGNETIC FIELD OF THE MAGNETS IS CONDUCTIVE TO RF.

A No ground plane antenna does not require a car body to work. That's why they call it a no-ground plane antenna and it can be installed on a fiberglass car or whatever.

A magnet mount antenna cannot work on a fiberglass car. You could duct tape it on there, but it will not tune because it needs the ground plane provided by the metal truck body.

Agreed!!! I have used a wilson mag mount, both the wilson 1k and 5k and they work just as well as any hard mount antenna... I too have tlked all over the world on mine before I drilled a hole, just for a more durabable mount...

I'll pm ya my call sign ..73's bud!!! Jeff
 
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