RFI in my cruiser (1 Viewer)

[jonheld]

I have the exact same issue. When the compressor of the ARB kicks in, my Kenwood radio becomes an outboard motor. I suspect because both are being fed from the same aux fuse block, but I haven't had time to mess around with it. I did not have this problem in my other truck with the same ARB but the power source to the 2 devices was different.

 

[NW Wheeler]

I have the exact same issue. When the compressor of the ARB kicks in, my Kenwood radio becomes an outboard motor. I suspect because both are being fed from the same aux fuse block, but I haven't had time to mess around with it. I did not have this problem in my other truck with the same ARB but the power source to the 2 devices was different.

Outboard motor is a good description of the noise I experience. Is the Kenwood a ham or a AM/FM Stereo? The fact that your problem appeared in the second truck is interesting, as one of the things I am wanting to narrow down is; is the problem simply a non FCC compliant fridge or do I have some simple installation change that will solve the problem.

I did several tests (with the braided wire kit installed, 15" length of 1/4" braid zip tied to some of the wires, purchased as a kit from ARB grounded to the fridge frame):

1. When the interference occurs, remove the antenna connector from the radio, if the noise ceases the interference is coming in through the antenna, the radio is quiet with the antenna disconnected.
2. I removed the antenna coax from the routing along the power wires and had the antenna and coax in free air to see if that helped - did not.
3. The power wires for the radio and the fridge are run together for over one half of the distance. I did plug the fridge into the cigarette lighter figuring that wiring is taking a different route than the dedicated circuit I ran for the fridge - did not reduce noise.
4. Powered the fridge with 115V AC with the 12VDC unplugged, this was interesting as part of the time the radio is quiet but still picks up noise part of the time, when I plugged the 12VDC in while powered with the 115V, the noise comes back most of the time. Appears that the noise is being picked up via the antenna and the power wiring (also shown in item #3).
5. With a Yaesu DC Line Filter LF-1 plugged in at the radio: powered the fridge with 115V AC with the 12VDC unplugged, part of the time the radio is quiet but still picks up noise part of the time, when I plugged the 12VDC in while powered with the 115V, the noise comes back most of the time. Filter had little effect, filter is intended to block ignition noise that I was getting on my CB, but am willing to test anything at this point!
6. Powered the fridge with 115V AC with the 12VDC unplugged, moved the antenna to many locations (coax in free air) on top of the vehicle where the antenna lives the noise is steady, turn the antenna horizontal and the noise is gone, with the antenna two feet outside of the vehicle at the right rear passenger door (open) about five feet from the fridge it will pickup the noise, forward by the right front passenger door (open) it is better. Moving the antenna all over the place showed that the spurious signals are really bad emanating from the fridge.

 

[Fast Eddy]

Do you run a fridge insulating bag? Make a full cover out of surplus anti-static bags and tape and it will kill the problem 100%. It's a cheap, easy test. Then, incorporate the static bags in with your existing or a new insulating bag and you'll be all set.

For extra credit, you could try to find the electronics of the fridge that are causing the problem, and just insulate that compartment with the material from the static bags. It could be tough to insulate it to prevent the RF and still allow it to be properly cooled.

 

[NW Wheeler]

Yes, I bought the fridge bag. Have you seen this solve the RFI problem? As I understand it, RFI and Static Electricity are two different animals. Cooling would be an issue as the vents are around three sides of the electronics/compressor/fan compartment. It would be simpler than a lot of the other possible fixes I have read about. I have been thinking about the bag, it has what appears to be a metallic looking material on inside, of course it doesn't cover the vents.

 

[jonheld]

Outboard motor is a good description of the noise I experience. Is the Kenwood a ham or a AM/FM Stereo? The fact that your problem appeared in the second truck is interesting, as one of the things I am wanting to narrow down is; is the problem simply a non FCC compliant fridge or do I have some simple installation change that will solve the problem.

I did several tests (with the braided wire kit installed, 15" length of 1/4" braid zip tied to some of the wires, purchased as a kit from ARB grounded to the fridge frame):

1. When the interference occurs, remove the antenna connector from the radio, if the noise ceases the interference is coming in through the antenna, the radio is quiet with the antenna disconnected.
2. I removed the antenna coax from the routing along the power wires and had the antenna and coax in free air to see if that helped - did not.
3. The power wires for the radio and the fridge are run together for over one half of the distance. I did plug the fridge into the cigarette lighter figuring that wiring is taking a different route than the dedicated circuit I ran for the fridge - did not reduce noise.
4. Powered the fridge with 115V AC with the 12VDC unplugged, this was interesting as part of the time the radio is quiet but still picks up noise part of the time, when I plugged the 12VDC in while powered with the 115V, the noise comes back most of the time. Appears that the noise is being picked up via the antenna and the power wiring (also shown in item #3).
5. With a Yaesu DC Line Filter LF-1 plugged in at the radio: powered the fridge with 115V AC with the 12VDC unplugged, part of the time the radio is quiet but still picks up noise part of the time, when I plugged the 12VDC in while powered with the 115V, the noise comes back most of the time. Filter had little effect, filter is intended to block ignition noise that I was getting on my CB, but am willing to test anything at this point!
6. Powered the fridge with 115V AC with the 12VDC unplugged, moved the antenna to many locations (coax in free air) on top of the vehicle where the antenna lives the noise is steady, turn the antenna horizontal and the noise is gone, with the antenna two feet outside of the vehicle at the right rear passenger door (open) about five feet from the fridge it will pickup the noise, forward by the right front passenger door (open) it is better. Moving the antenna all over the place showed that the spurious signals are really bad emanating from the fridge.

TM-V71A Kenwood dual band ham. The radio in the other truck is a TM-271A 2 meter. The only difference between the 2 trucks is the way the power is run. Same antenna mounts, same path for the coax, same radio location, same power port location for the fridge.

 

[Fast Eddy]

Static bags work on any RF emissions. Put one on your cell phone and see if you have any bars.

Metallic-looking material and an actual anti-static bag are not the same thing. If the main part of the emissions come out of the vents, however, you may need to get creative. It should be possible to create an RF cover over the vents with stand-offs that would sufficiently stifle the RFI.

 

[land crusher]

Have you seen this solve the RFI problem? As I understand it, RFI and Static Electricity are two different animals.

https://en.wikipedia.org/wiki/Faraday_cage

 

[WB8LBZ]

Has any one with this problem tried using ferrite beads or toroids on the power/antenna wires?

Larry in El Paso

 

[NW Wheeler]

https://en.wikipedia.org/wiki/Faraday_cage

Thanks Fast Eddy and Land Crusher,
Read the Wikipedia link and it makes sense since the anti-static bags are conductive. The fridge mounting location has some room around it and building an offset wall outside of the vents is preferable to running braided wire all over inside. May have some pink anti-static foam that could provide some structure.

Larry, I have verified that most of the RFI is making its way into the radio via the antenna (see post above), I still may be able to use the beads or torrids on the power wire to really clean things up.
Off topic: Read the introduction to your Veterans Highway thread, great idea and thank you vets for your service. I have not served, although our son has been in the Coast Guard for 7 years and our son-in-law in the Army for three years.

 

[NW Wheeler]

This post is equal parts WooHoo! and embarrassment. I had the idea that it was OK to connect the coax to the radio, run the coax out the door and slap the mag mount antenna (tuned) on the roof as I have done this with the CB for several years with no issues. Well not so with the mag mount for the ham, after much testing to figure out how to block the RFI I was hearing on the radio I finally figured out that the coax pinched in the door seal does not work for the ham. I bought another identical mag mount antenna ran the coax out of the window (no pinching) and no interference! The shield had been damaged enough to allow the spurious signals from the fridge to reach the center conductor. No question, I am an Amateur ham radio operator.

 

[Fast Eddy]

That brings up the idea that you could use a hand-held radio as a scanner for RF within the rig.

You would have quickly found that it was not the fridge at all.

 

[NW Wheeler]

That brings up the idea that you could use a hand-held radio as a scanner for RF within the rig.

You would have quickly found that it was not the fridge at all.

You could use a hand-held or when a mag mount antenna is available pass it around the fridge or other equipment to find the source of RFI. In my case it was very clear that the RFI was generated by the fridge. Of course with the smashed coax I was working with it would be difficult to pinpoint the exact location. With the new coax I put the antenna near the fridge and found that the fan is the worst offender of the various electrical and electronic components in the fridge.

 

[alia176]

Bringing this thread back to top vs creating a new one:

I am experiencing some RFI on 146.400 and 146.395 but not on 146.405. At least that's what I can recall from last week's trip CO. This intermittent RFI is breaking my squelch on the permanently mounted mobile radio which is cranked all the way to max. This mobile is a FT-1500 with a hard wired antenna and has a software squelch vs an actual knob.

This RFI issue is new, as of this year and I'm racking my brain to figure out what might've changed in this vehicle. The vehicle is a 2003 4runner V8. I can't seem to locate the source of this RFI in the 4runner by turning on/off various things inside the cabin.

Things I've tried while the RFI noise was occurring:
- turn XM radio on/off - no change
- turn the fridge on/off - no change
- asked convoy friends to turn their radio on/off - no change
- changed antenna - no change
- Turned mobile radio off, turned on Baofeng HT - can't recall what the result was. I think I still had the noise. Will drive the 4runner this week and retry this test.

Again, this isn't a constant RFI, just intermittent. My 80 has a cooling fan in the center dash over the radio but this 4runner doesn't have one. So, something in my 4runner is coming on/off based on some predetermined period but it's not happening predictably.

RFI filters might be a band aid and I'd rather figure out the cause of this RFI. I might borrow a second mobile radio to see if it still occurs.

This is new as of about a year or so.

Might you have some ideas?