Interference - Engine Noise

[drock2]

If I use my CB while driving I seem to pick up engine noise through the speaker. Both the radio and antenna are grounded. The CB isn't wired directly to the battery, which I've heard could be a problem. I've also seen filters. What would be my best bet for fixing the problem?

[va3hub]

Originally Posted by drock2

If I use my CB while driving I seem to pick up engine noise through the speaker. Both the radio and antenna are grounded. The CB isn't wired directly to the battery, which I've heard could be a problem. I've also seen filters. What would be my best bet for fixing the problem?

The solution is to put a "Choke Filter" in line on the positive power feed.

I was able to get information on the WWW about this filter.......The NF-20 is one of the best DC power line filters on the market today. Better than the filters offered by the big chain stores. Handles up to 10 amps at 16 VDC maximum.

Tech Tip: If you plan to use this filter with a CB radio, you should test to make sure that the noise is actually coming through the power line. Simply disconnect the coax from the radio. If the noise disappears, the noise is coming from your antenna and a power line noise filter will not help you. If the noise remains after disconnecting the antenna from the radio, the NF20 should work for you.

I hope this helps.

[drock2]

Thanks for the help. I'll have to try it out with the antenna disconnected.

[va3hub]

Originally Posted by drock2

Thanks for the help. I'll have to try it out with the antenna disconnected.

Right on dude !.......just be careful not to key the mic with your antenna disconnected

[klogd]

if you find the noise is coming thru the antenna, then take a look at k0bg.com site for tips on grounding (bonding) etc, to reduce your noise.

[gewecke]

Opinions will vary on this,but another option would be to supply power to the radio direct from the battery using shielded cable such as a length of rg58. the center conductor to pos. and shield to ground of course.
I don't suggest using your vehicle's fuse block,because that can introduce the noise you're hearing. Although a filter as mentioned could be used too,good shielding often cures or reduces the problem.
N9ZAS.

[va3hub]

Originally Posted by gewecke

Opinions will vary on this,but another option would be to supply power to the radio direct from the battery using shielded cable such as a length of rg58. the center conductor to pos. and shield to ground of course.
I don't suggest using your vehicle's fuse block,because that can introduce the noise you're hearing. Although a filter as mentioned could be used too,good shielding often cures or reduces the problem.
N9ZAS.

Holy Cow !...no rope and use it as a boat anchor reply to fix his noise problem ? lol, just kidding

[nickcarr]

If it is noise from your alternator, then here's a good filter: NS1535: Antenex (Laird Technologies) Blackhawk Noise Suppressor 35 Volt 15 Amp

[BNSFrailfan]

You should post.....
DO NOT push the PTT Mike when the Antenna cable is disconnected from the Radio. That is a no no. You could severely damage your Antenna transmitter and the Radio. I found out the hard way.

[drock2]

Just finished rewiring the radio. It was getting power from the cigarette lighter so I wired it directly to the battery. What a world of difference! Thanks for all the pointers. That k0bg.com website is great too.

[kb2vxa]

Now the question is how to get rid of all that noise with the antenna connected? (;->)

[va3hub]

Originally Posted by kb2vxa

Now the question is how to get rid of all that noise with the antenna connected? (;->)

Are you talking about the SQ noise ? If so, all you have to do is turn the knob to the left till it goes away :0)

[JayMojave]

Hello Drock2:

Look up the ARRL RFI Book, it covers many RFI and EMI Interference issues. Its at:
ARRLWeb: ARRL Product Catalog

Most good radios will have a NB (Noise Blanker) on the radio that does a good job reducing some pulse type noises. Wiring the radio to the Battery is a good call. Both polarities.

Hope this helps
.

Jay in the Mojave

Originally Posted by drock2

If I use my CB while driving I seem to pick up engine noise through the speaker. Both the radio and antenna are grounded. The CB isn't wired directly to the battery, which I've heard could be a problem. I've also seen filters. What would be my best bet for fixing the problem?