RFI-GDO Garage Door Opener RFI Kit
This RFI-GDO kit is specifically designed to cure most garage door opener systems triggered by Radio Frequency Interference problems. The kit contains ferrite ring toroids (“Donut” shaped ferrites) for the AC power supply protection and “Snap on” ferrite beads for door sensor (2) lines and one manual on/off opener switch.
The ferrites kits are selected to eliminate RFI from in one of two ranges, Either Low Frequency (150 KHZ-10 MHZ) and part# RFI-GDO-LF or High Frequency (1-300 MHZ) with part# RFI-GDO-HF. The ferrites are easy to use, don’t require modification of the protected equipment and work in almost all cases.
What causes RFI?
Strong signals from nearby amateur radio, CB, military, AM/FM and other “transmitters” (such as microwave ovens, cell phones, computers, wireless phones, HDTV systems, home automation systems/light dimmers, variable speed motors, etc) that are picked up by long wires (“antennas”) running through the house electric power wiring or device sensor wires. These “antennas” feed the interfering signals into garage door opener causing it to halt operation or act intermittently.Note: Some of the new Garage door controls use DC motors and a Pulse Width Modulation (PWM) speed controller which can generate RFI into other electronics nearby. Use the RFI kits below to help suppress RECEIVED RFI and RFI TRANSMITTED by your garage door opener.
How to cure RFI
RFI can be stopped by suppressing the signal from the radio “transmitter” or suppressing the signal on the receiving “antenna” feeding the affected device or eliminating the RFI path between the source and victim devices. With the RFI-GDO kit, you run the wires entering the opener through ferrite cores right next to (or inside) the controller box. Ferrites do not affect the signals going through the wires but they resist the passage of common mode RFI keeping the RFI signals out of the opener and stopping the RFI from falsely triggering the opener. Some sensor lines may require multiple ferrite toroids to be most effective. Also the more turns around the toroid, the more effective the RFI filter.
Sometimes you may also have to change frequencies of your GDO to avoid interfering frequencies. Many Chamberland(Whisper Drive, etc)/Craftsman/Liftmaster GDO’s use 280-390 MHz or 315 MHz which may be be close to interfering transmitters. The RFI kit will help to suppress the interference common to all lines including AC and DC driven motors.LED lights or LED light dimmers interfering with Garage door opener: Some brands of LED bulb circuitry operates from 30 – 300 MHz and may cause RFI to the opener. Best bet is to try different LED light brands or remove LED lights from garage and surrounding area. (read: problem is not with the LED lights but the LED circuitry within the LED bulb)Wireless/wired Security Camera Systems can cause RFI - use the RFI-GDO kit to suppress AC induced RFI into the opener.
If the RFI is severe, you may also try placing an aluminum foil “tent” around the sides of the GDO (leaving the “front toward the door open so the antenna can still receive your remote signal).
What is included in the kit?
The RFI-GDO kit is meant to be used with an AC powered (possibly through an AC wall wart or inline dc power supply battery backup) alarm system with up to 3 input/output signal lines and a single power supply line coming into the device. Note: a standard 3 prong AC power plug will go thru the ring ferrite 3-4 times as the ring has an inner ID of 1.4"
TECH NOTE: We also stock RFI kits to protect effected devices such as garage door openers, computers (laptops, desktops), dsl/cable routers, ethernet hubs and many more devices. Remember there is always a “transmitter” and a “receiver” of RFI and the quest is to find and choke the “path” the RFI has selected – you need to add ferrites to both the transmitting side and the receiving side to eliminate RFI problems.
The RFI kits on this page only helps suppress RFI on the receiving side.Christmas lights or yard lights with switching DC power supplies are often the RFI source and a clamp on ferrite bead on the AC AND the DC side feeding the lights is needed to help suppress the switching power supply RFI noise. We have also had reported wireless HDTV boxes causing RFI to garage door remote openers.
Snap on ferrites on the power cord supply and/or switching the coax cable interfaces to CAT5 cable may also help solve the problem. Obvious Tech Note: make sure your remote batteries have enough energy to activate the GDO or the signal they transmit may not be large enough to over ride the RFI signal, but a fresh battery may be able to overcome the weak RFI source and allow the GDO to operate correctly.
$38.95
For RFI common mode suppression use, mix 31 is effective from 1-300 Mhz, mix 43 works from 25-300 Mhz, Mix 61 is for 200-2000 Mhz, and mix 77 favors .1-50 MHz. These frequencies are those of the interfering signal to be eliminated, not the operating frequencies of the equipment to be protected. See Mix Selection for other applications.
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Bead dimensions are shown in the picture below and in the table as A, B, C
Ferrite Bead Dimensions
Application Note: Use impedances for each bead at your desired frequency to select number of beads needed for desired Z. For example if you have a 50 ohm RG-8 coax cable and want a choking impedance of 500 ohms at 10 Mhz, you can check the FB102 column (since FB102 will pass RG-8 through its center ID) at 10Mhz and find that Mix 31 has a Z of 108 ohms/bead and Mix 43 has a Z of 91 ohms/bead. For 500 ohms we would need 5 mix 31 beads or 6 mix 43 beads to have greater than 500 ohms. Mix 31 has better response below 10 Mhz but above 10 Mhz mix 31 and mix 43 are very close. If you need more Z, just use more beads in series on the cable or use more windings thru a larger ID bead (e.g. USE FB102-31 for 4 turns of RG-8X for 16X increase in Z per bead – see pictures below for examples). Use Mix 61 for VHF and above for RFI/EMI suppression and below 30 Mhz for multi-ratio impedance transformers (baluns/ununs). See Mix Selection for other applications.
For extra large cables use the FB400-31 which has an inside diameter of 3 inches (76mm).
Frequency Range Comparison Chart
(FB56-xx size)
Multi-turn Common Mode Choking Impedance Increase Example (FB56-43)
Ferrite Bead relative size comparison
Left to right sizes: FB56 (ID = .25″), FB102 (ID=.505″), FB103 (ID=.77″)
SLIP ON Sizes for Heliax and Coax Cable
Cascaded Common Mode Chokes/Line Isolators/1:1 Baluns
 RG58 4 turns on 2 FB102-31 for 2000 ohms choking impedance |
 RG58 12 turns on FT240-43 for 4000-6000 ohms choking impedance |
Handy Wire Size reference for ferrite bead sizes needed
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Connector already on cable? See Snap On Ferrite Beads for convenient installation on cables with connector already installed.