Need help with CB

[Craig]

1064517

I've just installed my new Cobra CB into my jeep and am having problems with it. First of all, I have a good tuneable antenna, I've hooked up an SWR meter to it and for some reason I get a high reading on all channels...adjusting the top of the antenna doesn't help. I've tried it with the ground for the antenna both on and off and nothing. All readings are over 3 on the SWR. My second problem is when I transmit, for some reason my stereo is picking it up. I have a seperate power wire running straight off the battery and the ground is good. The wireing for the CB is completly seperated from the stereo. Would a noise suppressor eliminate this problem or is it common to all CB's? [addsig]

 

[bigTlilODD]

1064522

A noise suppressor should work. So should some type of ferrite bead, or torroid. These are those things that you see wrapped around your keyboard, monitor game controller cable. This helps reduce frequency noise.[addsig]

 

[MudderChuck]

1064579

If you are getting high SWR´s the first thing to check is the cable, simple continuity check from the center of the connector to the center of the connector, then again from the grounded out side of the connector to the grounded outside of the connector. Check the ground from the antenna to the body and the ground at the radio. Sometimes a radio just doesn´t like a certain antenna. You didn´t mention which type antenna you have, but if it´s a fiber glass type, check from the tip to the base for continuity. Excess cable wound in a loop will mess with SWR´s, as will testing to close to a building or a chain link fence. Opening and closing the doors will often change your SWR´s as will someone standing to close to the antenna. A ground plain antenna is disigned to be mounted on a metal roof and will often not work well mounted on a fneder, bumper or fiberglass top. Lastly, get another meter and cross check the results, I´ve seen two different meters give wildly different readings. If you have a built in watt meter, lower wattage output is an indicator of good SWR´s and high wattage output is an indicator of poor antenna matching. K-40 antennas seem to work well, and I´ve yet to break one off.

edited by: MudderChuck, Apr 17, 2003 - 04:57 AM[addsig]

 

[ROade]

1064590

Ive also seen that happen with a bad antenna.
Actually just last week.
If your running like a 4 foot fiberglass , I'd suggest a Wilson Silver Load or the FireStick with tuneable tip.


edited by: ROade, Apr 17, 2003 - 03:57 AM[addsig]

 

[jps4jeep]

1064610

What are some good mounting areas for a CB. Mines under the dash but I do not like how it is hanging there, pulling on the dash, and I don't want a tuffy overhead console cause I know my CB and linear amp will not fit. Any one tried under the rear seat?
Johnny[addsig]

 

[jprtroy]

1064629

The "bleeding" over your stereo is caused by A: too much power (the linear) and or B: the high SWR. Linears are typically "broadbanded" to work on the CB frequencies and the as such, are not filtered very well. Your stereo speaker wires are such that there length's are close to the resonant freuency length of wire for the CB band. (I.E. CB antena) Effectivly, becomming another antenna. After you get your SWR down to close to flat, the bleedover will diminish, but may not go away. Espiecally if you run the power.
Adding the torriod coil's will help remove the bleedover from your stereo, but you may find the speaker wires too short after winding them through the torriod's. The noise filters mentioned above, are meant for the power lines (12vdc pos & neg) and can help with ignition noise. They wont help at all with the stereo bleedover. That problem is totally CB antenna related.
Good luck.


[addsig]

 

[Craig]

1064706

Ok, I've got rid of a lot of the noise coming through the stereo by relocating the coax cable to my antenna. It was running alongside my speaker wires. It still comes through my stereo but not as loud and no more screeching sounds when I transmit. Now I've noticed that I get noise on the CB when I turn on my wipers or heater. The noise gets louder if I turn my heater fan up higher. I'm assuming that a noise suppressor will help out with this. What should I look for in a noise suppressor? Are there any certain brands that work better than others? Are they expensive? Thanks.[addsig]