Radio Interference

[Piratenorm]

Good morning. I installed solar panels in my Catalina 30 last season and have experienced severe interference on my AM/FM radio ever since. On the radio only, if I use the CD or my iPad everything is perfect. My Catalina's nav station is directly over the batteries, directly under the circuit panels and the drawer houses the radio, meter for battery condition (never caused a problem) and now the meter showing charge status of the solar panel. The charge controller is installed about a yard away on a tray in the aft berth area.
Moving the radio is not really an option. I have a controller allowing the VHF antenna to act as my radio antenna which is also in this same area. It's all pretty tight but before I installed the solar panel meter and controller everything was fine.
The installation was correctly made. I disconnected the antenna and ran an auxiliary one away from the radio to check but that made no difference.
Any suggestions?

 

[Chief RA]

Norm: I'm surprised that the solar system causes interference since its DC. Try wrapping the controller with tinfoil for a quickie shield and see if that stops it. Chief

PS: Will install my new DC, .7 avg draw 2.3cf reefer this week!

 

[jrowan]

Not sure why solar panels would create radio interference, unless the wiring connections are too close to your radio, which may not be adequately shielded. Have you checked something as simple as a loose connection at the back of the radio antenna junction, which may have gotten bumped loose when you installed the panel wiring? Everything is pretty close together at the electrical panel. I will say that my FM radio is far from my electrical panel, & still does not get a very good reception. You would think that out giant mast would create a naturally good reception, but there's so much metal on the boat that can create reception interference.

 

[Don S/V ILLusion]

I disconnected the antenna and ran an auxiliary one away from the radio to check but that made no difference.
Any suggestions?

Wrapping anything in aluminum foil serves only to mitigate radiated noise. From the description above, it's pretty clear this is conducted noise. The difference being the former is radiated through the ambient space; the latter transmitted through wires.

The only effective way to minimize conducted noise is to install ferrite beads or collars on the wiring. If that isn't totally effective, you can add small .01 uF capacitors on (i.e., between) the neutral wires to ground.

 

[Chief RA]

Don, I know all that stuff but its worth an initial try. We might both learn something about these controllers with regard to possible freq. radiation. Yes, filter caps might work but if they do it would not seem a solar system would be the cause of the problem. I am sure Norm will let us know. Chief

 

[Forrest15112]

Normally, ytou would try to isolate where the interference is coming from. We know it's almost certainly teh solar controller, but I am referring to whether it's on the DC supply, or RF generated. You indicated that the CD player and your iPad both sound fine. I'm assuming the stereo has a built in CD player and some type of audio hookup for the iPad. If it were on the DC, you would probably have the noise on those devices too. That leaves RF generated noise, probably from a microprocessor controlled solar charge controller. It should be reduced when you disconnect the antenna. Wrapping in foil might help some, but could lock heat in on a device that may need to dissipate some heat. If the housing for the controller is metal, try grounding the chassis. Try grounding the chassis of the stereo too. You could try to shield the controller with a grounded metal box or panel. You should also contact the manufacturer of the controller and explain your situation. You could have a faulty controller, or they may have a fix available already. Have you tried eliminating the antenna filter? Is the noise on the VHF also?

Good grounding can reduce or eliminate noise in many cases. Grounding everything to the same potential is important and would include the controller, the stereo, the VHF, and the antenna filter/switch.

 

[Chief RA]

Lots of boats do not have ground systems Forrest. We shall see. Chief

 

[Piratenorm]

All good advice. I knew all along it would be trouble shooting and mostly that's fun but time is less avail. and I thought I'd ask. Wanted to upgrade the stereo to one more modern that can charge my iPhone whole listening to the music stored there but not till I track down this problem. The housing for the solar controller is a hard plastic and it does create heat and dissipates it through a heat sink. And it is grounded. Oddly I bought a small length of antenna, unclipped the radio from the mast antenna and plugged that in and the further I went from the radio the better it worked, as long as I was holding on to it with my hand...which means I was the antenna. Put it down and the interference returned, though better than before. I'll get to the bottom and will let you all know. Thanks.

 

[Forrest15112]

The FCC regulates RFI from electrical devices, but I've heard solar power equipment is exempt from those regulations. It's best to try to reduce the interference at the source rather than at your radio if possible. Unfortunately, you will likely have to employ several different methods. You can do the following:
1. move the controller as far away as possible
2. twist the positive and negative wires together - input and output - not all together, but just the pos & neg of the input and then pos and neg of output. The idea is that where the wires cross each other, the induction will cancel the noise signal. The wires could be acting as an antenna transmitting the clock pulse or harmonics of it.
3. Add ferrites to all wires in and out. Installed close to the controller.
4. Mount the controller in a metal box that would help contain the RFI.
5. Try contacting the manufacturer. Chances are, it was made in China and reaching out to them is not really possible, but you can reach out to the supplier. This is a common problem in the solar power industry and they may be able to swap out yours for a "quiet" model. There may be some adjustments that can be done. For example, I have seen a manufacturer of a device that was causing severe RFI tweak the clock pulse to their microprocessor. They claimed the noise was eliminated, but it was just shifted to someone else's bandwidth. Maybe there's some easy adjustment to shift the noise around on yours. Not likely though.
6 Run a new antenna as far away from the controller as possible.

Good luck eliminating the problem. Curious, Is it only on the FM radio, or AM as well? Does it affect a portable radio in similar proximity?

 

[Piratenorm]

The FCC regulates RFI from electrical devices, but I've heard solar power equipment is exempt from those regulations. It's best to try to reduce the interference at the source rather than at your radio if possible. Unfortunately, you will likely have to employ several different methods. You can do the following:
1. move the controller as far away as possible
2. twist the positive and negative wires together - input and output - not all together, but just the pos & neg of the input and then pos and neg of output. The idea is that where the wires cross each other, the induction will cancel the noise signal. The wires could be acting as an antenna transmitting the clock pulse or harmonics of it.
3. Add ferrites to all wires in and out. Installed close to the controller.
4. Mount the controller in a metal box that would help contain the RFI.
5. Try contacting the manufacturer. Chances are, it was made in China and reaching out to them is not really possible, but you can reach out to the supplier. This is a common problem in the solar power industry and they may be able to swap out yours for a "quiet" model. There may be some adjustments that can be done. For example, I have seen a manufacturer of a device that was causing severe RFI tweak the clock pulse to their microprocessor. They claimed the noise was eliminated, but it was just shifted to someone else's bandwidth. Maybe there's some easy adjustment to shift the noise around on yours. Not likely though.
6 Run a new antenna as far away from the controller as possible.

Good luck eliminating the problem. Curious, Is it only on the FM radio, or AM as well? Does it affect a portable radio in similar proximity?

Now There's a Good Suggestion! I'll take a small portable radio I have and check to see if that experiences interference and if it goes up the closer it gets to the solar controller.
I have never heard of ferrites to put on the wires. Can anyone explain what they are and where I could get them? Is it something The Source (Radio Shop) would carry?
As always, Thanks. Chief, good luck with your reefer install.

 

[Chief RA]

Radio shack should have the ferrites as well as the filter capacitors if you need them. They isolate or smooth out/shunt to ground or common, any voltage variations or intruding frequencies. Yes, I like Forrests idea of using an independant portable radio for testing as well. He also provides you with the capacitor size in above comments.
Will start the reefer install probably today. Must get it up into boat while on trailer!
Chief

 

[Forrest15112]

http://www.gacopper.com/CopperMesh.html

The link above is for copper screen. You could assemble a shield/box if you get to that point. It would allow airflow. Also a good source for other grounding supplies.

 

[bawlmer]

I agree with Forrest. The controller sounds like the culprit. There are a lot of "best practices" to use to mitigate RFI. If you employ enough of them and have just a little luck it will go away.
Use ferrite beads. They really work. use them on all wires. Even (especially)control wires.
Shield the controller with copper screen or even aluminium foil as temporary fix. Attach it to ONE grounding point on the DC system. As stated previously most boats do not have a "chassis" ground but it needs to be at the low potential.
Also if possible consider moving the controller away from the AM/FM radio. That can make a big difference.
If the panels are mounted to a stainless steel structure (rails, etc) try connecting the structure to the DC ground.
Remove, burnish and reinstall all of your electrical connections in the area of your stereo.
Best of luck!

 

[Piratenorm]

Well, Ferrites are a new one on me. BTW, the culprit was the solar controller, proved it with the portable radio. But Radio Shack (The Source) here in Ontario doesn't sell them (should'a seen the look on the guys face when I asked for some) but eBay has many sizes of clip-on styles. Has anyone any experience with these? I'll order a pack and start whacking them on everywhere if they work, just want to make sure these aren't like magic pyramids or triangles or some other such hooey.
As for moving the controller, all the wires are cut to length, replacing them with new ones to reposition the controller would be a large cost I'd rather not incur. Besides, a 30 Catalina only has so much space. Thx.

 

[Chief RA]

Norm: Did you try shielding it with tinfoil? Something that simple can tell you if shielding will work.
Finishing all projects and running the correct rigging. Should have her in the water by end of month! Chief