Chamberlain garage opener causes RFI
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| Jan 25th 2020, 14:46 | |
K0NXMTotal Topics: 0 Total Posts: 0 |
I have a Chamberlain garage opener that was installed several years ago, to replace an older one. It causes RFI that is evident on AM BC and up to 80m. It has been suggested before that the LED bulbs in it may make interference, but the noise persists even with no bulbs. I have found the noise disappears when both the opener switch and the IR safety sensors (at bottom of door) are disconnected - the noise originates inside the unit, and is radiated along the control lines. So far, I've tried clip-on ferrites, LC low-pass filters, and toroidal inductors in series with the lines, to no avail. Maybe I need more inductance? Has someone else solved this issue successfully? Thanks, |
| Jan 25th 2020, 16:24 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
Just a turn or two is normally insufficient on 80M. You typically want 10 to 15 turns through a toroid. If the wires are thin it is more effective and cheaper to run several wires through a large toroid. I use FT-240-43 or FT-240-31 toroids--the latter is more expensive but a little more effective at low frequencies. Zak W1VT ARRL Senior Lab Engineer |
| Jan 25th 2020, 19:09 | |
K0NXMTotal Topics: 0 Total Posts: 0 |
Developing... I used a couple commercially wound toroids (about 20 bifilar turns each), in series with the lines from the sensors and the remote switch - no help. I have now also detected the same interference on some power circuits in the house, maybe it's coupling to the front garage lights that are in close proximity to the sensors. I think I'll try using shielded twin-conductor cable next, as I think I have it on hand. I never realized there was this problem until trying to get on 160... |
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