CB noise from pusher pump

[MHammer]

I have got a loud screech on cb from the pusher pump. I tried a filter on the power of the radio and that did nothing. I ran the ground for the pump up to the battery and that help a bit. I read to put a . 01 micro farad capacitor on the pump wires as close as possible, so I put a disk capacitor across both terminals of the pump and that helped some more put I still have noise on it. Does anyone else have some idea's for me to try? I'm sure someone else has dealt with this same problem.



Thanks

 

[bmoeller]

Is the radio adjusted properly? Squelch and RF gain? That can help, too.



Maybe try a relay on the power side of the pump? That way the pump will get clean power from the battery, and still be switchable power.



Is the radio getting power from the fuse block, or battery?



May need to add some ground straps from the body to chassis, engine to body, or clean the battery ground connections on the engine.



May need to add a ground wire from the alternator case to the battery.



Getting a good ground on the antenna mount(s)?



That is all that comes to mind at the moment.

 

[ToolManTimTaylor]

Sounds like the CB anntenna wire (Coax cable if you will) is wound into a loop or circle. Figure eight it or make a big ol ball so it does not become an RF trap.

 

[p-Bar]

Have you checked the "match" of the antenna? In my days of doing installs for a living that was a big cause. Not sure about tool man's idea since the cable is shielded. What kind of antenna are you using??

 

[MHammer]

The pump is wired with a relay from the battery and the radio is wired off of a painless wiring fuse panel under the dash that I installed. I can turn the squelch up enough to get rid of the noise but that is at about half up. If I just try the radio on without the pump running I can run it quite abit lower and not pickup noise. Everything seems to be grounded good but I will check if over good. There are no loops in the cable.



I tuned the antenna when I installed it, It is a 2 ft firestick with the adjustable tip. I know this is not the most ideal height antenna but it worked good before I put in the pump. It is tuned down to an swr of about 2. 2 I believe, kind of high.



Maybe I'm just going to have be live with it and turn the squelch up but then I cant reach as far either.

 

[p-Bar]

2. 2 is a little high that could be causing part of your problem. Another thought on the 12v side is to disconnect the 12v from the truck and hook it up to a 12 volt battery seperate from the truck and see if the noise is still there, that would tell you if it was coming thru the 12v or the antenna. Also check grounding on the antenna at the base of the antenna. Your 2. 2 is thru ch 1-40? how much is it changing?

 

[Gary - K7GLD]

High SWR might reduce antenna efficiency, but will NOT cause any significantly greater sensitivity to vehicle generated interference - nor will tuning the antenna make them go away!



The LP's in our trucks already have noise filters built into them - and unless the pump motor is defective, it usually does the job quite well. Is the noise you refer to steady in pitch and intensity? Will it vary with engine speed? Are there other motors running that might be creating the problem - heater A/C motor, some added pusher pump or a fan motor?



My added Carter pusher generated hash in my mobile ham radio setup, and a simple . 01 bypass capacitor totally eliminated it. The alternator on my '91 Dodge created some pretty heavy alternator whine, which I eliminated ny shielding the underhood wiring with aluminum foil that was well bonded to ground at various points along it's length.

 

[MHammer]

It is a carter pusher pump, 4600 I believe the 7psi one, which is generating the noise. The cb was quiet until I put on the pusher. I have a . 01 micro-farad capacitor on it but it didnt completely quiet it down, it did help though. The capacitor is a disk type could that be my problem??



The cb runs 2. 2 on channel 1 and 40, I was told to tune it so that on both 1 and 40 the swr was the same. Am I correct in this? I know it is a little high but that is from the short antenna being close to the cab.

 

[Gary - K7GLD]

It is a carter pusher pump, 4600 I believe the 7psi one, which is generating the noise. The cb was quiet until I put on the pusher. I have a . 01 micro-farad capacitor on it but it didnt completely quiet it down, it did help though. The capacitor is a disk type could that be my problem??



The cb runs 2. 2 on channel 1 and 40, I was told to tune it so that on both 1 and 40 the swr was the same. Am I correct in this? I know it is a little high but that is from the short antenna being close to the cab.

A disc ceramic cap should do the job quite well - on my Carter 4600, I put it directly across the power terminals - my truck is dead-quiet as far as vehicle generated noise is concerned - absolutely no difference in receiver noise with engine on or off. On mine, I also use a ferrite toroid in the positive power lead - not sure how much it helps, but it sure doesn't hurt!



Here's a pic of mine - the toroid is partly seen at the far right, the green bypass cap is seen at the base of the pump at the power leads:



#ad




Your 2. 2:1 SWR is OK - lower is always better, especially with some rigs that will start reducing output as SWR gets excessive - but that is usually above 3:1 or so

 

[Woodenhead]

I was getting some interference on my CB that was variable with engine speed (kind of a whining sound). The +wire is hooked direct to the battery and the -wire is connected to a ground under the dash. I figured the interference was coming from the alternator since on a 12Valve that's about the only electrical apparatus spinning in circles with the motor. Anyway, I ended up getting a little box to wire into the supply power that eliminated interference from dirty power. I think it had 3 wires, one +in, +out and a ground. Worked great and I don't have anymore interference.



Mike

 

[n7gxz]

MHammer.



Do you get the noise with the key in the on position but with the engine off or just when the pump is running? I was having a noise problem on my ham radio and it turned out to the the VA box. I see that you have a comp box, my comp box will also generate noise when I turn it on as well. Try unpluging or turning off you comp box and see if the noise goes away. If so you need to put a ferrite core on the cable coming out of the comp box. I can get you the part number of the ones I used when I get home this afternoon.



Here is a link to the ferrite cores that I put on my VA box.



Kevin