Noise from truck refrigerator

[Cg30sailor]

Having a problem with noise from truck refrigerator. Nothing when it is off. Tried 3 different radios. Definitely stops when you kill the fridge. Any suggestions?

[231]

Having a problem with noise from truck refrigerator. Nothing when it is off. Tried 3 different radios. Definitely stops when you kill the fridge. Any suggestions?

First off welcome to the forum. If you can't filter the noise via the radio, then you have little choice but to go after the device causing the RFI in the first place. Are you switching trailers regularly or is this a refer you use all the time?

Chances are the noise is getting in through the antennas so there isn't much you'll be able to do for that. It's not hard to confirm this by simply unplugging the coax and see if the noise goes away (or at least most of it). I'm not familiar with the motors the use on the compressors but if they are DC motors (which I'd guess) they are inherently noisy to begin with. No way around that other than throwing ground straps on them and adding torroids (ferrite beads) to the power and/or control leads to the motor. That might help allot. BUT...if you are changing trailers all the time then you are sunk.

I was sitting here wondering if maybe a noise phaser might help? What a noise phaser does is uses a separate antenna and allows you to phase at least some of the noise out. I run one in the shack because of all the neighborhood noise I get. But they aren't cheap. You could install it inline right after the radio. They are rated at a couple hundred watts, but no reason you need to put it after an amp, it can go before it.

I run the Time Wave ANC-4, but MFJ makes one too. I ran a long wire out as the receive antenna for it. In your case you could run another mobile antenna perhaps or a short 2m dipole, etc. The problem with them is you don't know if it'll be effective until you try it. And to drop $200 (or whatever they are running nowadays) on a "maybe" is sort of an expensive gamble. They do work though...just not on all noises. The don't work on plasma TV's I can tell you for sure. LOL! But something to consider. I would NOT buy a used one unless the person lets you try it first. Trust me, some guys overload them (usually put them after the amplifier, but not always), then try to fix them, then say they are working when they really aren't. Had a friend of mine do that and I opted for a new one instead. His didn't do anything but the new one worked like a champ (and helped allot!). I've been running mine for about 5 years now.

In any event, with a little more info' perhaps we can help narrow down your options. I think if you are changing refers all the time though, you'll have little choice but to consider a noise phase device.

231

[MDYoungblood]

Hello Cg30sailor,
Welcome to the forum. I do know what you are talking about, they are inherently noisy to begin with. 231 gave you a couple of things to try, older trailers though you might be out of luck. If it is a newer trailer try contacting the manufacturer, tell them it is interfering with your cell phone, you will get more of a response from that than if you say your CB radio. You could try googling the brand of refrigerator to see if there are any retrofit (RF) noise kits is being made for it. The only other thing I can come up with is to check out some of the trucker forums, this question has had to of been asked before.
I have one more idea, thought about it as I was writing, does the starter switch for the refer run inside the cab, if so, if you can unhook it on the outside, see if the noise goes away, if it does than put a couple ferrite beads on it. Just a thought.

3's

Greg

[Slyguy]

Having a problem with noise from truck refrigerator. Nothing when it is off. Tried 3 different radios. Definitely stops when you kill the fridge. Any suggestions?

Question. Are you talking about a "refer" or a small refrigerator in the truck itself? If you're talking about something in the truck itself, does it run off an inverter?

[Cg30sailor]

It's an installed in the truck refrigerator that came with the truck for peterbilt. You turn it off and you get no noise

[Cg30sailor]

It doesn't matter what type trailer. Reefer or van. Truck itself is only 1 month old. Frustrating. Thank you all for the replies

[231]

Ah, okay it's actually in the cab. There are several things you can do. That's actually allot easier to deal with than what I was thinking. And I would NOT look for any support from the factory...especially whomever built the truck (albeit they've probably had complaints on it already but didn't know how to deal with it). I would say though that if it's running off an inverter the inverter is likely part of the problem and certainly the place to start. I cannot tell you how many big rigs I've driven passed that were running inverters, and even on my Icom IC-7000 (which has some of the best filtering available) cannot filter it all out. I can sometimes begin hearing it 1/4 mile behind them, and doesn't stop until I'm 1/4 mile past them (and worse the closer I get). How they can listen to the CB I'll never know...because on my Icom it's something like 40 over s-9 when I go past them.

That being said, if the fridge is running on 12vdc from the truck you can add snap on ferrite cores to the power leads in. I would get the good quality ferrite cores from DX Engineering (google them). If needed, one of us can PM you the link for their snap on ferrite beads. But you'll need to add several, not just one or two. You may need to extend the input wiring to accommodate for that and wrap them around the ferrite beads as many turns as you can get. It may even be necessary to add a capacitor to help snub out the RFI. Hopefully that'll get the majority of it.

With RFI, you have to take it a step at a time and see what helps. I replaced the fuel pump in my pick up (Cummins diesel) a year or two ago with a Fass performance fuel pump. It's all that's available for it actually. It generated so much noise I had to basically do what I suggested above. It solved the problem 100%. What's worse is when I called the manufacturer they were dumbfounded that anyone would complain about such a thing. But the fact is it's cheap (no doubt import) motors they were using. The pump has worked great but like most OEM's, they play the odds. It's not a hard fix but necessary to go after the culprit, not filter the radio if possible.

Good luck.
231

---

December 24 2013

It doesn't matter what type trailer. Reefer or van. Truck itself is only 1 month old. Frustrating. Thank you all for the replies

It wouldn't matter if it's new or not, most manufacturers don't have the forethought to consider such matters. After all, the purchasers go with whomever has the best price for like items. Ask me how I know. They can care less about the customer having unintended problems with it as their job is done. So no sense in getting frustrated...if you are happy with the rest of the truck this may only be a minor hurdle.

231

[MDYoungblood]

Sorry Cg30sailor,
I was under the impression that it was a trailer causing the problem. Post the brand of frig so I can look it up and see what can be done to help with the problem. If it is running off an inverter like 231 said it is a 110v model. Good catch Sly, I'm too old and none of the tractors I drove had a frig inside much less a place to sleep.

3's

Greg

[Cg30sailor]

Yeah 231, peterbilt wouldn't really care Lol. The 3 other identical trucks don't have the issue. Thanks again guys!

[rayray1963]

The refrigerator in the new Peterbilt suck. They are cheaply built and are prone to issue's. Pull the unit from the cabinet and run a flat ground strap from the chassis of the refrigerator to a better ground on the truck like the frame.

[Slyguy]

The refrigerator in the new Peterbilt suck. They are cheaply built and are prone to issue's. Pull the unit from the cabinet and run a flat ground strap from the chassis of the refrigerator to a better ground on the truck like the frame.

Good idea!