Garage Door Opener RFI Kit

Magnetic Long Wire Antenna Matcher (9:1) for SWL, 100 KHz-30 MHz

SKU MLB-2
$79.95
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Magnetic Long Wire Antenna Matcher (9:1) for SWL, 100 KHz-30 MHz
Product Details
MPN: MLB-2

Palomar Engineers Magnetic long wire antenna matche has been redesigned for shortwave listeners who listen to a broad frequency range from VLF to HF and others needing to match a long wire antenna to 50/75 ohm coax feed line cable.

Specifications: Frequency: 100 KHz – 30 MHz. Input: 50/75 ohms for coaxial cable. Output: High impedance. Connector: SO-239 (for cable), wingnut/solder lug wire lead (for antenna). Mounting: Stainless steel eyebolt. Size: 2.5” diameter. Case: White PVC sealed weatherproof. External ground bolt with wing nut for external counterpoise or separate ground.

The long wire antenna often has a high impedance in the 500-1000 ohm range and the MLB-2 transforms this high impedance close to efficiently couple the received signal to the receiver. A long wire antenna with a matching balun such as the MLB-2 often has a 12 db (2 “S” units) better signal than a long wire without a matching balun.

Typical Installation Diagram

MLB 2 Installation Diagram - Garage Door Opener RFI Kit

MLB-1/MLB-2 Typical installation diagram

For best results we recommend that the coax feed line be at least 1/4 wavelength on the lowest operating frequency since the coax braid is used as a counterpoise if you don’t use the external counterpoise terminal on the matching unit. We also recommend a feed line choke at the end of the coax feed line near the radio to prevent RFI common mode current (from neighbor noise sources) from interfering with the radio – check out the info below on feed line chokes.

Also available as a complete ready to hang SWL antenna. (see related products).

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.  Suitable snap on beads are FSB31-1/2 for the 1-250 MHz range.

We have also had reported wireless HDTV boxes, and FOSCAM and AMCREST security camera systems causing RFI to garage door remote openers. Use our Garage Door Opener RFI kit to suppress the interference to the opener (VICTIM) – you need one kit for each opener.  Maximize the distance from the camera to the openers may also help.  Additionally shield cable to the garage door sensors may be needed depending on severity of the camera RFI.

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.