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So, I have recently moved my IC-7000 to my truck, connected to an ICom AH-4 tuner mounted in the bed for HF.? The 2m/70cm antenna is also in the truck bed.? When transmitting VHF, I am getting reports which seems to be ignition noise interference.

At this point, I have some the remote head cable wrapped though some ferrite.? Not sure what else would be recommended...just ferrite everything up as much as possible?? Any other ideas?

Grant? VA6GT

FWIW --

Two thoughts:

(1) Yes, ferrite the spark-plug wires, and the alternator wires, as
well as the remote head cable. You don't say how the signal reports
are on HF, when the truck's engine is running -- are they OK?

(2) I had a lesson on my boat, that may be relevant if you're running
VHF while the truck is moving:

. . . DON'T use audio compression, in a high-noise environment.

"Compression" boosts low-volume sound (from the mic) by quite a few
dB. That's useful to increase average talk power, if the environment
is quiet.

But if the environment is noisy (e.g. a moving vehicle), it destroys
the inter-word gaps in your speech (by filling them with boosted
ambient sound), and you become unintelligible over the air.

Ferrites are cheap, relative to how much good they can do.

On Mon, Apr 15, 2024 at 4:46?PM VA6GT via groups.io
<va6gct@...> wrote:

So, I have recently moved my IC-7000 to my truck, connected to an ICom AH-4 tuner mounted in the bed for HF. The 2m/70cm antenna is also in the truck bed. When transmitting VHF, I am getting reports which seems to be ignition noise interference.

At this point, I have some the remote head cable wrapped though some ferrite. Not sure what else would be recommended...just ferrite everything up as much as possible? Any other ideas?

Grant VA6GT

Alternator whine or ignition buzz? I've never had reports of ignition noise going out over the air. I get plenty when on receive. However, the IC7000 Noise Blanker always seems to do the trick in greatly reducing it. I have had reports of alternator whine when transmitting FM on 2M.? It's usually been much lower than voice so I never tried eliminating it. The cars have all been Ford Taurus or Mercury Sable. I currently drive a VW Passat and no alternator whine. I do get ignition noise but I simply punch the NB and its not a problem.?

Speaking of spark plug wires I have tried both shielding and ferrites and in both cases the car didn't run very well. I don't advise that. I helped another ham with alternator whine by installing a brute force line filter in the DC run to his rig. That made it barely perceptible. He started running the rig from the cigarette lighter and the whine was really bad. Next he ran 12v directly from the battery and the noise wasn't so bad. Adding the line filter nearly eliminated the alternator whine.?

Hope this helps. My IC7000 has been my mobile and portable rig exclusively since I bought it in 2007. I like how I can place the rig under the passenger seat and use my nifty cup holder mount for the control head. Works great.

73, Larry W7DGP

? When transmitting VHF, I am getting reports which seems to be ignition noise interference.

I'd be surprised if it was ignition noise.? Modern ignitions usually have the coils right at the plugs, there's no wire there to shield or put a ferrite on.? If it's popping it could be the DC going to the coils, or more likely, injector noise.? I've never had this on transmit but the fix for that could be as simple as isolating the DC to the radio (ferrites, bypassing, choke).? Where you're getting the power and ground for the radio can also influence the level of any interference that might be present.

Mark K5LXP
Albuquerque, NM

I am announcing a 50amp 12vdc emi filter at Dayton it might be of interest to the group.
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