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Help with making cb less staticy?

Max Attitude

Max Attitude

Typical White Person
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Location
Alto, MI
Ok, I have the Cobra 29 cb pictured below. I got it from a guy for $20....came out of a semi. I have 2 3' Diesel brand whips that connect with a Y wire to the cb. Ever since I have had it I can't hear crap outta it. It's either way too much static or I never hear anybody loud enough...no matter how I tune it with the nobs. Do I need to bring it somewhere to get tuned better or turned up somehow? Are antennae boosters obtainable? I've heard they are illegal but not sure. I also have the external speaker pictured mounted below....any ideas where I could fit it? I might see if I can get it under the seat. I might not be able to use it...probably made for semi-trucks. I don't want it to stick out.
Also, do I hard wire it to the cig lighter or where?

picture.php


351472914.jpg
 
Ok, as for losing the static, adjust your squelch JUST enough for the static to go away, no more.

There's something called a CB Linear; yeah, they're illegal in some places but they're in every truck you see :)

You could take it to a CB shop to get it 'tuned', sometimes the antenna's and the unit need a SWR meter to tune in correctly... If I'm not mistaken that radio has one built in but, I forgot how to tune them :( Sorry.
 
Well first off, never wire to the cig lighter. You will get alot of feedback through that alone. Have you adjusted your SWRs? They need to be 1.5 or below. I would go ahead and run power wire to the battery and a good ground to the chassis. If you still have alot of noise then you need to look into a filter.

I saw in your album were your antennas were mounted. That is a good spot but not a good length antenna. You will need something much longer if you want to reach out in front of the truck. Radio waves will bounce off of your cab and deflect rearward giving you no frontal coverage. If you stay with that mounting location and duals go with about a 6' or so antenna, or a flexible metal style with magnet mount on the roof for best results. Don't forget to ground your antenna to the chassis if it is not magnet mount.

Make shure you are running a high quallity coax. These diesels have alot of interferance with eletricals since they inject their fuel at 24-26000 psi. That takes alot of electricity.
 
bccorvette said:
Well first off, never wire to the cig lighter. You will get alot of feedback through that alone. Have you adjusted your SWRs? They need to be 1.5 or below. I would go ahead and run power wire to the battery and a good ground to the chassis. If you still have alot of noise then you need to look into a filter.

I saw in your album were your antennas were mounted. That is a good spot but not a good length antenna. You will need something much longer if you want to reach out in front of the truck. Radio waves will bounce off of your cab and deflect rearward giving you no frontal coverage. If you stay with that mounting location and duals go with about a 6' or so antenna, or a flexible metal style with magnet mount on the roof for best results. Don't forget to ground your antenna to the chassis if it is not magnet mount.

Make shure you are running a high quallity coax. These diesels have alot of interferance with eletricals since they inject their fuel at 24-26000 psi. That takes alot of electricity.
Click to expand...

Hmm, well I don't want to go much longer...maybe 4'ers. I think it's more interference that i get than feedback. I think I remember almost hearong the turno through it, haha. Maybe part of that is using the cig lighter like you said. Would a filter help? How much are they, where do they go/look like?

High quality coax for what? The antennas or power for the cb? I bought the antennae wires from a truck stop so they should be good. The power wores for the cb I also got from the truck stop.
 
Jasondt2001 said:
Ok, as for losing the static, adjust your squelch JUST enough for the static to go away, no more.

There's something called a CB Linear; yeah, they're illegal in some places but they're in every truck you see :)

You could take it to a CB shop to get it 'tuned', sometimes the antenna's and the unit need a SWR meter to tune in correctly... If I'm not mistaken that radio has one built in but, I forgot how to tune them :( Sorry.
Click to expand...

Is this what you're talking about? http://cgi.ebay.com/Astatic-1K-Line...4|66:2|65:12|39:1|240:1318|301:1|293:1|294:50

Or like this? http://cgi.ebay.com/CB-LINEAR-AMP_W...4|66:2|65:12|39:1|240:1318|301:1|293:1|294:50

Could I put that in a discrete place and still have it work good? I like the looks of my whips. :D
 
see where you ran your coax cable that will affect it a lot. if you are running it parallel to the trany or anything like that you will get interference. try the squelch that could be the problem as well. you want to squelch it down just until you dont here the static anymore. .
 
Try only running one antennae, thats what I do on the little trucks. Helps a lot so they dont cancel each other out.
 
eng158 said:
see where you ran your coax cable that will affect it a lot. if you are running it parallel to the trany or anything like that you will get interference. try the squelch that could be the problem as well. you want to squelch it down just until you dont here the static anymore. .
Click to expand...


Hmm, I have the wires zip tied to whatever within the frame rails under the truck. How do you run yours? Mine go down between the bed and the cab then up through the firewall.

I tried adjusting everything including squelch and volume...nothing helped.
 
Head on down to Radio Shack and tell them you need an inline capacitance choke (RF Filter, or attenuator) for your power input line.

Run both power AND ground directly to power source (battery or direct line, pref. battery)

You can buy all that at once:
plf-10m.jpg


Make sure that your coax, if it crosses any electrical lines, does so at 90* angle to avoid induction.

Make sure the CB body is well-grounded.

Hope this helps... if not, send a PM to RadioMan... he's a Member here, in the 6.5 section, and he's a certified genius at 2-way and HAM radio stuff...
 
Loose the dual antennas. Duals need to be more than a 1/4 wave apart to work effectively. CB runs in the 11 meter band. Measure the distance between you antennas and do the math - I am sure they are closer than 2.75 meters (~9+ feet)
 
JiFaire said:
Head on down to Radio Shack and tell them you need an inline capacitance choke (RF Filter, or attenuator) for your power input line.

Run both power AND ground directly to power source (battery or direct line, pref. battery)

You can buy all that at once:
plf-10m.jpg


Make sure that your coax, if it crosses any electrical lines, does so at 90* angle to avoid induction.

Make sure the CB body is well-grounded.

Hope this helps... if not, send a PM to RadioMan... he's a Member here, in the 6.5 section, and he's a certified genius at 2-way and HAM radio stuff...
Click to expand...

I was looking on ebay and was just going to ask about this....is the one in the link the same thing? Good or bad price? Thanks
http://cgi.ebay.com/Pyramid-Noise-S...h=item280273787451&_trksid=p4634.c0.m14.l1262
 
minisub said:
Loose the dual antennas. Duals need to be more than a 1/4 wave apart to work effectively. CB runs in the 11 meter band. Measure the distance between you antennas and do the math - I am sure they are closer than 2.75 meters (~9+ feet)
Click to expand...

Well that's dissapointing to hear...I already have the money into this setup. I'm going to try it with the noise filters and stuff....if it still don't work as good as i want I will change it. I'm not looking for real long distance....just clarity for a couple miles.

Thanks everyone for the input.
 
Nope. RF int comes from your power side... clean that up first and you should be OK.
 
If you are going to do anything with your antennas, I would raise the mounting so they stick up a bit more above the cab, or extend the mount to get them out from behind the cab. Make DARN sure you have really good antennae grounding... if your antennae don't have a good ground, they can't establish a good ground plane, and having that reflective component is fully half of your performance.

The purpose of having duals is to increase your fore/aft gain; as long as you can keep them within 9 feet of each other, and give them a clear 'view' of the road, you can get that elliptical field wihout losing too much on your lateral field.. If they are less than 4.5 feet apart, you might as well run a single - in which case I would get it up on top of the roof to maximize the ground plane.

Or... you could put on one of those 108' steel whips on a big spring (just like in the 70's) so you could crease your truck when you were off-roading :)
 
Eh, well the purpose of duals for me is mostly looks. I did think it would help in the beginning but I still really like how they look. :smile5: As for raising the antennas...I was going to get the springs for them so that will help lift them up a little bit.
 
Don't coil up any excess coax; it shouldn't be in a neatly wound circle. You want it balled up with as little coiling as possible; even the best shielded coax will cause interference problems.
 
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