Recently installed a Ham radio in my truck. The noise from the engine on the radio makes it useless while the truck is running. Has anyone successfully filter it out or atleast reduce it to an acceptable level? Have narrowed it down to being picked up by the antenna and not the power source. I believe the injectors are the cause.

Any suggestions?
1999 F350 PS

Mike

 

i hooked mine to the battery on the driver side and it does not make as much noise..

 

Mike,
What bands are you having problems with? I have an IC-7000 in my truck and I get pretty bad injector noise on 40m, but that's about it. It's funny you bring this up because I am finishing my install this weekend and plan on grounding the engine, tail pipe, and truck bed to the frame in multiple places.

I also noticed that I get some trash on 2m when I turn the key on (truck not started yet). That's another issue I hope gets fixed by grounding some of this stuff. If it doesn't help, then I go to plan B, and that's where I start breaking out some ferrite & bypass caps.

On another note... Ron! I didn't know you were an Amateur!

Joe
Amateur Call N3JI

 

up here with all the mountains we need the big radio's to talk long distance..

I have a connex general hill with a +10k..its the same as the galaxy DX33HML
I then had it peaked and tuned and run a Wilson 2000 ant..it did pick up better when the radio was in my bronco..but in my PSD I found it to be a little better going strait to the bat. with the pos. a neg wire..then to get a live fuse in side the cab...I picked up an old fuse box from a junk car..I want to run 30 amps from the bat to the fuse box using a noise resister.(cant seem to find a good one yet).then use fuses to run my radio and other things from that fuse box..

 

Hey Joe,

I've seem to notice the noise on 40m, 30m and really bad when listening on 11m. When on 2m I can hear it but not bad. I have a Yeasu FT-857D. Ordered two ferrite kits from DX Engineering, should get next week. I've grounded the tail pipe, hood and the mount for the hamstick that is mounted across from the stock antenna. Didn't make any noticable difference.

Mike
KI6LNC

 

This is sorta up my alley, ( I work for a two way radio company, doing anything from mobile service and installs (just got back from butler, pa and worked on state police cars all this week) and 911 console work, and tower site work.) You said you have your antenna mounted right accross from the factory stereo antenna? And you also said youve isolated it from the power side? (assuming you used a battery not connected to the car to power the rig?) IF so, I would mount the antenna on the roof towards the rear. Alot of people are scared of leaking etc, mines an 02, had 3 holes in the roof since it was new, just so long as you install it correctly youll be fine. PSD injectors are noisey, they do have 120ish volts going to the injectors. Some have been noticeably noisier then others. We have power line filters that are manufactured by Johnson radio (used to be big, but made a good filter) but they are only rated for 10ish amps IIRC, ill have to check. If you are running a 100 watt rig, your more then likely drawing 20-25 amps on fm and similar at PEP on am. In which case these wouldnt do much help. I would seriously consider a roof mount towards the rear of the vehicle.

 

Did you try grounding the bed to the cab?? Check out this page:
http://www.w8ji.com/rf_noise_powerstroke_diesel.htm

Ron......

If you have some time, I'll tell you why "peaking up" a CB just isn't a very good idea...

I beleive it's the PCM running that causes the trash on 2m. It happens before the truck is started, and no difference at all when it's running. I've run all bands but 30m in my truck with a screwdriver and 500W HF amp (pulls ~90A by itself!!) -- no issues except what I already described. I *will* figure this out, though...

Joe

 

"Grounding the bed" really shouldnt affect him at all. The reason IMO the fella on that site had an improvement is because his antenna was mounted on the bed.

Also, saying all the RF current must travel throught the front of the cab, then frame etc is misleading. The RF current actually flows through the center conductor of the coax. You could mount the antenna off the vehicle, on a platform (a tower for instance) and the only physical attatchment between the antenna and the radio is the coax. And still have perfect SWR, and amazing receive (due to antenna height) and the only noise would be from outside sources IE power lines, etc. Im not saying that the ground braid he put on didnt help him, but I think his explanation was misleading.

Mike
KB3HJI
(yes Im technically a ham, but I got my license for other reasons a looong time ago, before I became a radio tech)

 

Another thing, what is the noise you hear? My bosses 02 has a popping noise, thats rpm related, and its at UHF, but hes too lazy to fix it as its his older truck, whereas my truck does not, but we have two very different electrical systems in our trucks. Do you have a picture of your antenna mount? What kind of coax did you use?

 

Mike, he's talking about the return. Once the RF gets to the antenna, it's using the body of the truck as "the other half" of the antenna, and it capacitively couples to the earth for the rest. When you don't have the outer skin bonded well (in this case, the truck bed & body -- but it could also be hood, doors, truck, etc.), the RF takes alternate paths to get where it wants to be. Just like when you connect to a "real" dipole up in the air, the RF "tries" to be only on the hot side wire, and the wire connected to the shield of the coax (or other half of twin-lead if you use that instead). In the real world, dipoles and in this case, the mobile antenna working against the body of the truck, aren't perfectly balanced. When that happens, the RF doesn't "know" it's only supposed to use the other leg of the antenna or outer skin of the truck -- it just as easily flows down the outside of the coax shield (This is a separate path than what's on the inside of the shield! You have to think of it that way). When that happens, it's now back at your radio (which is how "RF in the shack & "hot mics" happen, BTW), going down the power leads, then to the battery back to the body & frame. It would also use the short lead the rig is grounded to the body with (HOPEFULLY!!) as a return path.

When in a mobile, you can't just think of the antenna as the radiator. Particularly on HF, the whole vehicle becomes part of the antenna system and that's why it's important to have everything bonded well. Especially the bed to the cab, and engine & exhaust pipe to the frame in multiple places. Now add a 500W HF amp to the mix and it *really* gets fun...

Joe