Troubleshooting Electrical Noise

papageoff · June 7, 2017

He's got a President McKinley. It's bone stock, but is a very nice radio overall. Something interesting is that on SSB, I have to use the clarifier to get him sounding good, but I'm dead center on his clarifier. I don't think that really means anything significant, but we suspect his is a bit off tune.

We came to the same conclusion as you about most of our distance-contact issues being antenna related. He's in a Taco and has been using a 2' on the back of the bed mounted to the cargo rail system they have (jealous). This last test we did he used a 3' in the same location. I've been using a 3' mounted to the back of the toolbox. It's more centered, so I should have a more even radiation pattern than his. I would think his is radiating heavily forward which works against our test.

As for SWRs, I haven't been able to get 1:1, but I'm getting 1.4-1.6 on my 3' firestick. Somewhere just short of half of it is above my cab. His SWRs are 1.8 on either end. He gets about the same clearance over his cab. I know neither of them are great, but we're short on open fields to test in. So, it's hard to get it dialed in perfectly.

sdeeter19555 · June 8, 2017

He's got a President McKinley. It's bone stock, but is a very nice radio overall. Something interesting is that on SSB, I have to use the clarifier to get him sounding good, but I'm dead center on his clarifier. I don't think that really means anything significant, but we suspect his is a bit off tune.

We came to the same conclusion as you about most of our distance-contact issues being antenna related. He's in a Taco and has been using a 2' on the back of the bed mounted to the cargo rail system they have (jealous). This last test we did he used a 3' in the same location. I've been using a 3' mounted to the back of the toolbox. It's more centered, so I should have a more even radiation pattern than his. I would think his is radiating heavily forward which works against our test.

As for SWRs, I haven't been able to get 1:1, but I'm getting 1.4-1.6 on my 3' firestick. Somewhere just short of half of it is above my cab. His SWRs are 1.8 on either end. He gets about the same clearance over his cab. I know neither of them are great, but we're short on open fields to test in. So, it's hard to get it dialed in perfectly.

I would do three things if it was me...1) have the radio aligned and tuned, 2) upgrade coax, 3) swap out the firestick for a stainless 102" whip and 6" spacer or spring (need 108" total).

I ran a 102" whip in the location you describe, ran almost 1000 watts through it...1:1 SWR. Had excellent receive and transmit, even barefoot...shot a lot of barefoot SSB skip crosscountry too.

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Jeremy01 · June 8, 2017

Long time ago I had this problem with one vehicle and the radio come to find out it was a spark plugs wires that were not insulated properly the yellow high-performance spark plug wire does not block electrical interference I found this out because I was doing a tune-up did not have this problem before it so I would suggest trying to put an insulator on your wires if you have stock wires

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sdeeter19555 · June 8, 2017

Long time ago I had this problem with one vehicle and the radio come to find out it was a spark plugs wires that were not insulated properly the yellow high-performance spark plug wire does not block electrical interference I found this out because I was doing a tune-up did not have this problem before it so I would suggest trying to put an insulator on your wires if you have stock wires

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Mine seems to be alternator whine, not ignition.

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papageoff · June 8, 2017

I don't want a tall whip. As for the tuning I've found couple places online that I might send the radio to. I'd be worried anyone local is a hack. From everything I've read/watched on youtube, this radio isn't very friendly to tuning and it's easy to make it really bad.

I've been toying with the coax idea, but I just don't want to go through the hassle of replacing it ~~if I can avoid it~~ if I'm not certain it will make a difference.

Last night we repeated that test. I could hear some noise from the truck. It's not a lot, but it's there. It does seem intermittent, though. I didn't have a lot of time to play with it, but I'd swear it was in time with the injectors and I heard it more when it went into v4 mode and on SSB. I'm probably imagining the v4 part, but it's definitely a rhythmic click.

I am going to try to retune the antenna to see if I can improve that. Something interesting about that... I bought an SWR meter when I got the radio. If I use the built-in one, I have even and reasonable swr. If I plug in that meter, the number immediately shoots to over 3 on one end. I don't know if the meter/cable is bad or if the antenna length is just that sensitive. The short cable meters out properly between ground-center, center-center, and ground-ground.

I've spent a lot of weekends on this project and my wife is getting impatient. So, I may have to live with it like this for a while.

Jeremy01 · June 8, 2017

All I can say at this point is get out there on the radio and start talking to the local people that are on the radio see if you can hook up with a radio Tech the main thing is to get your SWR as slow as possible especially when you go to add extra juice to it and if your radio has not been tweaked get it done where I am at there is no radio shops anymore like there used to be so this is the only way you're going to get your situation taken care of but I still say you are getting your interference from your plug wires

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Jeremy01 · June 8, 2017

And the length of your coax is divided by 3 feet exactly so your main coax to the antenna should be 18 feet and your jumper between your box should be 3 ft or 6 ft depending on where you put it in your vehicle and a lot of your Fire Sticks are adjustable at the top long time ago the old one did not have that knob to adjust them the newer ones do get your SWR down as low as you can

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papageoff · June 9, 2017

I would do three things if it was me...1) have the radio aligned and tuned, 2) upgrade coax, 3) swap out the firestick for a stainless 102" whip and 6" spacer or spring (need 108" total).

I ran a 102" whip in the location you describe, ran almost 1000 watts through it...1:1 SWR. Had excellent receive and transmit, even barefoot...shot a lot of barefoot SSB skip crosscountry too.

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Out of curiousity, what would be your coax recommendation?

sdeeter19555 · June 9, 2017

I believe RG-8 and RG-8x are typically the standard for an mobile install. RG-8x is the thinner and more flexible of the two from what I remember, which makes installs in mobiles easier.

I was running RG-8 in the last truck, this one is whatever a Wilson 5000 roof mount comes with since I'm not running power anymore. I am sort of out of that scene, have a batch of radios and whatnot and only have one installed.

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