• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
  • Click here to find out how to win free radios from Retevis!

dx99v engine noise

wilson04

Member
Nov 29, 2009
31
4
18
Can anybody help me out? I have a dx99v that is getting engine or alt. noise. I have grounded everything I can and I still have it. It even has a mild hum when the engine is off and acc. is on. I've unhooked the ant. and it is still there so I dont believe its that. The thing is, I only have it with this dx99v. My other radio's don't do it. Any advice would be appreciated. Thank you.
 

Wecome to the forum, Wilson04!

1) Run the radio power directly to the battery; this way you won't need to turn the key on.

2) The alternator brushes and bearings may need to be replaced. Or buy a new/rebuilt alternator if it just too old and worn.

3) Spark plug wires should be replaced if they are old, dried out, and brittle. They can generate RF due to micro cracks/spark gaps inside the cable itself - unseen to the human eye.

4) Turn the key to the 'accessory' position. Go to the vehicle's fuse panel and remove one fuse at a time until you find the offending circuit. Then use you vehicle's owners manual to find out what is on that circuit. That should speed up the process in finding the guilty party a bit.

5) Build or buy a noise filter/suppressor and hook it up between the battery and the radio. They are pretty cheap to buy and even cheaper/better to build your own from scratch...

6) Remove and clean the ground strap between the engine and the frame. Replace it if it looks dicey.

I'm sure I left something out, so others will chime in as well.
Hope this helps some...
 
Last edited:
Thanks for your advise. I'll try #1, #4, and #5. The vehicle is a KW W900L. The alternator is fairly new and I just did the new ground strap to the frame. Any Idea why it only does it with this radio? I'v had a couple of cobra 29's and a 959 hooked up and they don't produce any noise. Could there be any weak caps in the radio or anything like that?
 
My DX 99V has a very sensitive receive - probably better than the Cobras for sure.
I have an '08 Honda CR-V that I get absolutely no noise from - whatsoever. Never hear any static from my car. I would continue to look for problems from the vehicle itself. Probably you just have to find the offending circuit - IMO...

When I do pick up noise, it is when I am driving about.
It can change as you move closer to businesses or noisy power poles.
You environment around the car can change noise vastly.
If the car is near the house when this happens, the refrigerator, plasma TV's, or any number of appliances can add to what you are hearing in your receive.
 
Last edited:
Thank you again. I will stay focused on the semi now. I'm gonna try the options you mentioned earlier. Thanks again for the help.
 
If you have noise with the key just in the "run" position, but with the engine off, the first place to look is the fuel pump. You can pull the fuse for that first to see if that's the offender.

Some radios have better Noise Blanker and noise rejection circuits than others. To be honest, a lot of the export radios are just horrible at picking up all kinds of noise. There are some threads on this site from a few years ago that described the problem of how they have too much gain in the first RX stage, along with other issues.
 
  • Like
Reactions: Slowmover
I checked everthing over and ended up putting an inline noise fiter on. That eliminated all of the noise. Thank you for all the help.
 
  • Like
Reactions: Slowmover
If you have noise with the key just in the "run" position, but with the engine off, the first place to look is the fuel pump. You can pull the fuse for that first to see if that's the offender.

Some radios have better Noise Blanker and noise rejection circuits than others. To be honest, a lot of the export radios are just horrible at picking up all kinds of noise. There are some threads on this site from a few years ago that described the problem of how they have too much gain in the first RX stage, along with other issues.


Too much sensitivity to vehicle-generated noise seems reasonable. It’s worth swapping a few other radios (types) in & out to assess that.

A backup radio is (should be) SOP for a truck driver. And a non-Export type ought to be that choice (Uniden 980, IMO). That’s first.

Try (also) something like a Cobra 29 Classic (as test equipment). A dozen or three at every truck stop every night.

.
 
I checked everthing over and ended up putting an inline noise fiter on. That eliminated all of the noise. Thank you for all the help.


(I know it’s ancient, but . . . . )

Specifics, please, (if you read this.)

1). POS (fused) to BATT, and NEG (unfused) to Frame?

2). Total length of POS/NEG circuit, and AWG-size?

3). Ran wiring from BATT box thru firewall and up to overhead behind panels?

4). Filter brand & amperage rating?

5). Location where installed?

Thx

.
 

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Mark Malcomb:
    Hello BJ. Been a long time since I've been on. You doing well? Mark Malcomb
  • @ Naysayer:
    I’m
  • @ kingmudduck:
    Hello to all I have a cobra 138xlr, Looking for the number display for it. try a 4233 and it did not work