I have a cobra 29lx with a Wilson 2000 mirror mount and after market rg8 coax. So the problem is that when I'm sitting still I have my squelch up about a quarter way, but when I start driving I have to turn it up to almost half why. What would be the best way to fix this problem? This is installed in a peterbilt 367. Power and ground ran direct to the battery, and a ground ran to the mirror mount, I have a 1.5.1 across all channels. Thank for the help in advance.
Does the static change( increase or decrease) with different surfaces, and does it go away when you apply the brakes or when the road is wet or its raining? If yes its probably coming from the steer tires. There have been articles on the net about adding graphite powder to the hub oil or installing a ground strap with metallic in it and let it drag on the road.
No it does no matter what surface I'm on, and it doesn't make a difference if I touch the brakes our if it's raining or dry. The other day it went all day on a quarter way up and never made a static noise, then at the end of my work day it started doing it. I didn't know if adding rf chokes would help me or not.
Could just be atmospheric conditions...Most of the time during the day my noise level is around 2...But one day last week the noise level was almost at 7...Seams like usually when the noise level is high, is when DX is rolling...Usually the noise will die down some after dark. Might see if the noise level is higher when the motor is running...Could be your just picking up interference from the trucks electronics...If that's the case, best thing to do is some RF Grounding with ground straps. I never had much luck using ferrite beads, but I know allot of guys swear by them.
Thanks do you mean ground strapping the fram and cab? It's all the time when I start driving. I had a guy tell me to put loops in the coax, but I had another guy tell me that was to help out with the swrs. I'm new to this. Just trying to find out if it's normal or not. Thanks for the info.
When the band is open, the noise level naturally rises. You have dozens of signals, each contributing to the overall noise floor and only the strongest will be intelligible. Sporadic E propagation (the only regular openings we see this far down in the solar cycle) tends to peak in the late afternoon or early evening here in the northern hemisphere, and normally dies off after dark. That may account for what you ate experiencing.
If it's engine noise, you can run flat ground braid from things like exhaust pipes, cab (unless it's fiberglass, then there's no point) to the frame...Doors can be grounded using short ground braid from the inside of the door, to the door jam or body of the cab...More metal you run ground straps off of to the frame the better chance you have of reducing the noise...Probably won't get all the noise out, but you can get it lower...Important to use the flat ground braid and not round wire. If you have some old coax, that makes good ground braid. Just strip off the outer coating, then pull the center conductor wire out, which will leave you with just the ground braid. You can take that, and flatten it out and use it...What I've done, is once I have my ground strap,I will melt some solder on the ends, then use self tapping screws to attach the wire to the truck...Having the solder on the ends helps keep the screw from just pulling threw the wire when installing. One other note...Try and keep ground straps as short as possible...And make sure your coax from the antenna is not right up next to wires that have power running threw them...
I will try the old coax trick that's one I haven't heard of yet. It's an aluminum cab so it should ground. My antenna is next to the radio antenna do you think that will play into it?
A quick way to tell where your noise is coming from, is to simply remove the coax from the back of the radio. If the noise is still there, its coming in from your power supply. If it goes away, its coming from the antenna side. This just helps to narrow the source down. The coax choke you mentioned, is to help keep cmc (common mode current) off the coax. Simply put, this is when some of your signal is being transmitted from the coax. Adding the ground straps like JJD says, is a crucial part in increasing the effeciency of your antenna system. I second that recomendation...just keep them as short as possible as he said. What type of ground do you have ran to your mirror mount? And where does it run to? If its just a length of random wire, it could be a possible noise source. Also, sometimes it can be beneficial to run your power straight off the battery....sometimes not. Alternator whine and ground loops are common when using the negative battery post as a ground source, unless the radio is the only thing grounded to that post. You might try grounding directly to the chassis..
The power is the only one ran off of the battery right now. I was going to run a ground to it when I go back to work Monday.The ground going to the mount is coming from the frame to the mounting bolt. So if I unhook the coax will I have to adjust the squelch like normal and the see if I have to adjust it when I start moving? I kind of wonder if the coax being feed through the mirror arm that has a temp sensor wire going through it to has anything to do with it. Also it's ran behind the dash and up the door pillar. That was the only way to get the coax in there with out having pinch points.
