CB Problems

[Tank33]

Hello all, I am new here so first off let me just say hello to everybody!

I am currently driving a 1999 Freightliner FLD120 and recently made some changes to my CB system and ever since I have had nothing but a fight with it.

When I first got into this truck, the antenna's were mounted on a 2 inch long 1 inch wide bracket (I assume it is steel, did not look to close but there is some rust on it) This bracket was bolted on through the use of the bolt on the top, outside mirror bracket. I am a fan of tilting the antenna's forward, I like how it looks, so that was the first thing I did. I purchased 2 aluminum antenna mounts that clamp onto the mirror bracket itself and mounted my antenna's tilted forward.

In the process of doing this, when I was removing the coax the first time, one of the coax cables broke free of its connector, and I had no time to pick up and run new coax, so I left it. The radio stopped working well from here on in, and so today I decided to fix it.

I picked up new coax. Now, it IS cheaper stuff, it is the black stuff from Peterbilt. I ran a coax to each antenna, and it feeds into a Y adapter on the back of my CB, which is a Cobra 29 LTD ST. So coax on both antennas is brand new, radio is about 5 years old I guess, but was working great before I moved the antenna's. I also purchased a new microphone today as the wires pulled out of the 4 pin connector on my old one. My new microphone is a Cobra M75 Power microphone.

Even after I turned the radio on and tried again, I could hear others talking, but they had to be fairly close (500 feet or so??) I tried many times to get a radio check, and no answer, even though plenty of people were talking. Yes, there is a battery in the microphone.

My question is. Am I doing something wrong? All I want is like, 5 miles of range, and clear crisp receiving and transmitting, does not have to be the world's best, I just want it good and understandable. One thing I did not do, I had a good amount of excess Coax, I DID NOT, fold it end to end and cable tie it up, I simply pushed it all into my headliner to hide it, nothing is bundled up.

So to sum it up my equipment is:

Aluminum antenna mounts, mounted on aluminum mirror brackets.
Peterbilt 4 FT fibreglass antenna's.
Peterbilt 9 FT coax on each side, fed into a Y adapter.
Cobra 29 LTD ST Radio.
Cobra M75 Power Microphone.

Am I doing anything wrong, how can I make this a good reliable working CB system with what I have??

Also, what is the difference between a powered microphone and a non-powered microphone?? I picked this one off the wall in a fair hurry, and when I opened the packaging was shocked to see a battery cover and a hook up for a 9V battery. What is the purpose and advantage (if any) of these microphones??

Thank you!

[Rat]

Ok. The original setup was cophased and when the one end was not hook up it sent the swrs through the roof more then likely. If you are going to run just one antenna then you need one single coax cable of 50 ohms or radio damage will happen. You can not just unhook one antenna and run it that way on a cophased setup.

Another issue could be your mounts. They need to be on a clean rust free surface that offers a good ground. If you have a ohm meter then check for continuity between the bracket and a known good ground. No ground = bad.

Now you are going back to cophased. Are these new coax 75 ohm or 50 ohm. You need 75 ohm for a cophased setup and not 50 ohm. 50 ohm is for a single setup only.

As far as bullhorning your antennas. Anymore then 10 degrees hurt performance. Don't bull horn them unless they need to be. If they are flexing back while going down the road and getting to close to the stacks or other metal objects then the swrs will go up. Then bull horn them a little bit. But being these are the shorter Rami (peterbilt) antennas then I don't see this being a problem. Them antennas are junk for the most part. I have 5 sets here that are bad. the main wire is broken in all of them and they are not that old.

Your best bet is to go to a truck stop and get a cophased coax setup. They are not that expensive to start with. I perfer the hgiher quality Belden coax but that is me.

Give that a try.

I see you are running a cobra 29. It has an swr meter function. Although it is not the best it still can get you close enough for what you are running. If your SWRs are more then 2 when you key up on channel 20 then you may need to look at the setup better. The cobra manual tells you how to check the SWRs.

[Brickhauler]

One other thing, you might have hurt the radio if you talked a lot when the old coax was disconnected on one side. Your new mic is amplified and your 29 also has an adjustable mic gain knob. If you turn them both up all the way, you might be over modulating when you talk and real hard to understand. It will talk some experimenting to find out how much is enough but not too much.

[Rat]

I agree with the above. Not a big fan of powered mics personally. I think they ruin the audio and would rather hear someone on a nice noise cancelling mic such as the Astatic 636 or the Road King 56.

[Tank33]

Well, I guess I should have researched this a bit more first, that was $55 wasted!

I will have to check the coax next time I go to the truck, I am unsure as to what it is, it was wrapped hanging on the shelf, had no packaging or anything, so unless it says it on the cable itself, I am unsure.

Is it possible to use the power mic. I have without a battery in it, would it function like a normal mic. with no battery?? I could always turn the mic down, not? It has a dial on it.

Are there any kits available with good antenna's, and good coax, something that takes all the guess work out and all that needs to be done is installation?? The only kits I ever see have the shorter "ant" style antenna's on them.

Reason I am running those antenna's is this is a company truck and I am short on money at the moment, I do not want to put $150 worth of antenna onto a truck I do not own and could be switched out of at any time.

EDIT: I forgot to mention, my mirror brackets are on my doors on this truck, not on the body of the truck itself, so every time the door is shut I am sure it puts great stress on the antenna as it is whipping around in all directions. I am guessing chances are good these cheap antenna's are shot as well?

[Tank33]

Also

If anyone could please tell me, what are some nice good antenna's?? I am kind of unsure as to what is good, or worth buying.

Thanks.

[25(2)+2]

Rg6 and rg59 are 75 ohm cables, rg8 and rg58 are 50-52 ohm cables.

If you are going co-phased, buy the ready made assembly unless you know exactly what you are doing.

[25(2)+2]

Originally Posted by Tank33

Also

If anyone could please tell me, what are some nice good antenna's?? I am kind of unsure as to what is good, or worth buying.

Thanks.

I have a Wilson Silverload, a 5/8 wave antenna. Running with a legal CB they work pretty well, and I only run a single.

[Rat]

Many people run Francis Antennas with very good luck. They are extremely inexpensive and usually don't require any type of tuning.

Diesel has some dual "kits" I have used them and just upgraded to better antennas later.

At current I am running Wilson 5 ft fiberglass antennas. They have been working just fine lately. I had gotten a couple bad ones and had to repair them but now they are working fine.

Oh if you are running duals (cophased) then get them as far apart as you can. Some people have been able to get them to work when they are closer together but most can't and need to get them as far from each other as possible. So get them out to the ends of the mirrors.

[Tank33]

OK, to update.

I went and picked up some new antenna's this afternoon. They are 4 1/2 foot Francis antenna's. I also picked up 2 antenna springs, I am sure some people will say they are cheesy, and a waste of money, but I liked the look of them and I thought they might help when slamming the door, that way the spring takes most of the shock and swinging, and not the antenna.

I checked my coax, it is RG 59, so if I am understanding what I have been told correctly, this is the right stuff for a cophased setup. Everything in this entire CB system is brand new, except for the radio. New coax, new mounts, new antenna's, new CB mic, and I STILL cannot get it to work. I get the static and all that, and I can barely hear others talking, and not very many people, just a few, everytime I try to transmit, the white needle in the gauge on the radio spikes to about 80% of the right side, just over where the red starts.

Not to sure what I am doing wrong here, maybe the radio is shot too??

Where the coax feeds into the Y adapter coming off the back of the radio, I could not get the right side coax cable to push into there all the way. It is about 80% of the way in, and in there tight, but it is not in there all the way, would this be an issue?

Also, is it possible to use a powered microphone without a battery??


I appreciate all the help folks, hopefully I can get this figured out!