Adjustable 80mm causing interference w/ ceiling fan remote...

[Zim Hosein]

Okay, I figuring this thread could only belong here, it not let me know.

Here's the problem, I have a Hampton Bay ceiling fan w/ a Hampton Bay wireless remote to control fan speed and turn the lights on & off. The problem is that when I have my Enermax externally adjustable 80mm case fan turned all the way up to its fastest setting, the ceiling fan remote will not work, turn the 80mm case fan down and it works fine

Any idea why this happens?

 

[wacki]

Just to let you know, this isn't a troubleshooting thread, but this is an odd enough problem that I will try and help.

Do you have a window on your computer or a grill over the fan ports? The computer needs to have a metal cage (can be solid or open wire mesh) all around it to prevent RF leakage. Do a google on "Faraday Cage Shielding". Also look at your fan remote, if you see a LED or little window then the remote is IR. If no window, then it's RF. The fan should only be able to interfere with RF remotes, but even then it's unlikely. But I've heard of stranger things.

 

[klaviernista]

yeah, you have some RF leakage in there somewhere. The frequency of the interference will change as the motor speed in your case fan changes. Unlucky for you, the case fan appears to be putting out RF at the exact frequency that your ceiling fan remote uses.

The cheap way to prevent this from being a problem is to go to the store and get some very fine mesh (the finer the better) of aluminum (i.e chicken wire) or other metallic wire (the higher the conductivity of the wire the better, so if you can find copper mesh thats great). The mesh used in conventional sieves would work quite well. You can try putting (i.e. taping or adhering in some way) the mesh over suspect portions of your case (read: places in your case where there is no metallic substance between the interior of the case and your room). The most likely culprit is the place where your case fan exhausts air into the room, but it could be anywhere. Try adhering mesh around the entire case and seeing if that helps. If it doesn't, yopu may need a finer mesh, or you can switch to a metal foil (i.e. aluminum foil) instead of the mesh. ONce you've got the problem fixed, try removing portions of the mesh to narrow down where the leak is coming from. Then you can just shield that area instead of your whole case (and avoid the weird looks you get from people when they see your computer looks like something from a 1960's science fiction movie.

The reason I suggested mesh in the first place (as opposed to foil) is because it is likely the problem is coming from your fans exhaust outlet and you likely do not want to black that outlet with a solid sheet of material. The mesh allows your fan to exhaust air from the case and will most likely block your leak (unless the RF leak is extremely high frequency). The mesh works extremely well so long as the mesh size is finer then 1/4 the wavelength of the RF radiation you seek to block, as most RF will see a mesh having this mesh size as a solid sheet and specularly reflect.

Oh! And you might want to see if your ceiling fan can be prgrammed to use an alternate frequency. Some of the later hunter style fans have multiple frequencies available (this same problem happened to me when I installed a new ceiling fan in my kitchen and my old microwave was prefventing the veiling fan remote from working.

Best of luck

-klav

 

[Safeway]

Very interesting indeed. My Bose RF controller did the exact thing, but I was too late to chime in.

 

[blahblah99]

Most like the fan speed is PWM modulated... if you would just shield the fan wires as much as possible by wrapping aluminum foil around it and grounding it to the case, it would help a tremendously.

Or try orienting the fan wire so that there is metal shielding between the wire and your remote.

It looks like to me the frequency of the PWM modulation (or it's harmonics) is close to the remote's frequency. And at half an amp with a 1 foot wire, that's enough to generate enough radiation to screw things up.

 

[kautilya]

shields are the best way to go. though you may try what software engineers usually do. remove the fan and reinstall it works like a charm sometimes

 

[sao123]

i cannot use my tv remote control when my microwave oven is running...any idea if that is a similar phenomenon?? Theyre not even in the same room, like 20 feet apart.

 

[klaviernista]

Originally posted by: sao123
i cannot use my tv remote control when my microwave oven is running...any idea if that is a similar phenomenon?? Theyre not even in the same room, like 20 feet apart.

If your tv remote is RF, then yes, its the exact same thing. And 20 feet is not much distance when it comes to RF interference. Radar Jammers in the military are basically huge RF emitters and can work on detectors that are positioned many miles away.

I'd be willing to bet your microwave is fairly old if you are having that much interference. Most new microwaves have to pass stringent shielding standards because microwave radiation is known to interact with human cells in unpredictable ways

 

[Zim Hosein]

Now I know why I don't venture into HT too often, most of this stuff is way over my head

Thanks for all the replies so far fellow members, I appreciate it and I'm reading up more on the subject

Again, thanks :beer:

 

[sao123]

actually my microwave and tv are both brand new as of sept 03.

 

[Tiamat]

I remember back in the day when I was driving my R/F car along the street, it would open/close the garage doors of my neighbors. Wasnt a very safe thing.