Since it is raining cats and dogs, I decided to work on the noise generated by the JK that I hear on my Yaesu FT-100.
I dug thru my parts box and found a ferrite donut tht would fit over the Alternator output. Not sure of the mix, but the size was right. After removing the battery connections, the wire was easy to remove safely. Will see if there is any improvement tomorrow.
Next I looked into the spark plug wires. After a careful inspection of the crimp connection at the coil, I could see that it is a carbon type. as a side note, I pulled the plugs. They were clean, but after 30k miles, the 0.50" gap had opened up a bit. I reset and reinstalled. Finally found a replacement set of plug wires at magnecor dot com.

I contacted them via email about trying a KV85 CN25 8.5 mm set. Will report any findings here.

N4XGI

 

Definitely let us know of your findings....

 

For sure !! Good luck..

 

First the Ferrite on the alternator lead. I could not tell much difference with the noise blanker on. With the NB off, there is still noise that rises and falls with engine rpm that sounds like spark plugs or possibly fuel injectors. Since this is the most prominient noise and could be masking other noise, this has to be cleared up first.

So on the Magnecor. I got a email reply today.

Our best suppressed cable is our "CN series" 8.5mm cable, which will reduce the noise from the wires as much as possible (but will not reduce noise from other sources) while still giving you a metallic wire that in normal circumstances should never have to be replaced.

The price for a CN series set for a 2007 3.8 V6 Wrangler is $138.00 (part no. is 63294); shipping cost is $8.00 extra.

I am going to order a set in the morning.

N4XGI

 

I have not dug into my noise problems at all because of time and weather, or lack of good weather I should say.....

I did notice that my 102" is picking up just about all if not all the noise, with the coax removed from the back of the 2970DX noise level drops to about zero...Being the 102" is mounted on the rear tire carrier of the Fab Fours bumper I'm wondering if the 102" is picking up fuel pump noise....

Thats where I'll start looking first is fuel pump...

 

I have received the red 8.5 mm Magnecor CN wires and installed them yesterday before leaving for the Georgia QSO party. These are a excellent quality product. The drivers side is easy, but the passenger side turns into a job getting them routed around the back of the engine. The factory wire looms will no longer work on the larger diameter wires. I will go to the parts store next week and see what I can find.

Now for the results. There is still noise on my reciever with the engine running. But it is different, so the wires have reduced some of it. My JK has 30k miles on it so the factory ones may have started breaking down.

But I think there is more work to be done.

I do not hear any noise with the ignition in the ACC position, and a short burst when turning the key to ON. (fuel pump?) With the engine running, there is a poping noise that varies with engine rpm with Noise Blanker (NB) off. Could this be fuel injectors? The noise is more pronounced on 40M and reduces as I tune up the band. The NB now does a better job, so this means to me the level of noise has gone down.

The hunt continues.....

N4XGI

 

Ya.....I was gonna say as well, those big filter caps can do wonders somtimes.

A few things.....

Well it's good to see that the plug wires made a difference...........but damn they are spendy. But I know......quality comes at a price. Hard to believe that at only 30k miles the originals were already breaking down. Not surprising tho......as these car comps. are always cutting costs to make it afforable for us to buy the damn things....!!!

Have you run any ferrites on the power lead to the radio itself?

Fuel pumps have always been notorious for causing noise. THAT would definitely be a good bet as "some", if not all, of the problem.

As far as the popping noise........what do they use for coils in these rigs nowadays? I just remember the old style coils used to make popping noises.
I haven't a clue as to the injectors...I know very little about them.

Again.....in the old days, we used to pull the alternator wire, but I've heard that doing that these days can "possibily" mess up your alt. I don't know if this will, or how it can, but it's what I've "heard"........so do that at your own risk.

And yet again (in the old days...lol) we used to have the rig running and just start pulling fuses.......sometimes it would work like a dream to find the culprit. But I don't know how problematic it may be to try and do this on the JK. I would imagine there again, might be the chance on screwing something up.

I haven't installed an HF rig in the JK yet.......but I do know that when I do, and if we can't figure out the problem/s, I WILL be bringing it to a friends "Auto Electric" shop we have up here. Do you have something like that in your area? I would think they would be able to find a noise pretty easy....???

Good luck and keep us updated....
73 & Thanks......

 

Keep the ideas coming. I think working on the quality of the installation is part of being a ham. If we were to get a few sunspots on a regular basis I think we would be discussing QSo's, etc.

Dont get me wrong here - the noise is not a deal breaker for working HF. I have made nearly 100 HF contacts on 40, 20, 15M with only 100W while mobile since the first of 2009(Stateside and DX). I just want to reduce it to a minimum. The plug wires allowed me to reduce the NB setting from 9 to 7 (full scale is 16) before the poping noise is present. I can hear the engine noise from another passing car.

I may be rapidly nearing the point of dimishing utility.

The coil is 6 coils in one package.

There is no continous noise with the key on and engine not running. I am not sure that pulling fuses is a good idea.

I do have a ferrite on the power, several of them.

The sound of an alternator is more of a "whine" that increases in pitch with rpm, as apposed to a poping noise. I do not want to run it without a load. I would take the belt off first.


N4XGI

 

WOW.....still 7 S units of noise.......that still sucks big time. I only say that because during quiet conditions, many times I have worked stations that don't even read an S unit.....audio only. And many times just atmospheric noise can be S5 or more.....not including static crashes from lightning. So yes......you want to get it to a minimum, if you want to hear signals (with the jeep running) under S7.

BTW......There is no S unit over S9. From 1-9 is the basic report scale. What the "16" on your radio means is decibels OVER S9. That's what it means when you hear somebody say "your 5, or 10, or 20, over". What you would say if somebody peaked your meter, would be.....you pegged me at 16 over S9.

As far as hearing noise from other vehicles, you know there's nothing you can do about that....right? Because that's noise that your antenna is picking up from their rig.

No, it may not be a good idea to pull a fuse in these newer vehicles. I only said that because it never used to hurt anything on the old rigs.

Remember, police vehicles have to deal with noise too. Of course most of their stuff is VHF, but cops used to run CBs too. Plus they have to deal with noise from other things...(puters and such) inside the rig. It may be a good idea to try and find out where they take their rigs to install their radios. Those folks may have a good idea of what gear makes noise.

btw......did you find out anything with the fuel pump?

I don't remember or not........before you started adding ferrites, did you start your JK with the antenna unhooked from the radio? Was there much, or any noise then? That tells you for sure if it is noise coming in via the power or ground leads. Then you could work on those one at a time before you hook your antenna and try to isolate the noise that it picks up.

Did you check with Rat Shack yet to see if they still sell those big filter caps you could hook up to the alternator? I know I still have one somewhere, I'll try and find a part number for you.

Carry on my friend and good luck......

 

That 1-16 NB adjustment scale is not in S units. Just a reference to NB level. Even with the RF gain at 100%, my JK engine noise does not even indicate on the S meter, but I can hear it. As far as weak signal go, I am one. I like to listen for other weak signals. If I can hear them, I can usally work them.

I have asked for detailed signal reports and never has anyone commented that they hear anything but my audio.

N4XGI