MFJ-2912 Instruction Manual
Wall-Mount Balun
3
MFJ-2912 Wall-Mount Balun
Introduction
The MFJ-2912 is a wall-mounted 1:1 balun that keeps RF current
traveling on the outside surface of coax cables away from station
equipment and internal house wiring. It also prevents electrical
noise generated in the building from migrating up to the antenna
feedpoint and raising the receiver noise floor. The wall-mount
packaging provides a convenient disconnect point for lightning
protection. Disconnecting the antenna from the building is the
most effective method for preventing equipment damage from on-
site lightning strikes. Bottom-mounted SO-238 connectors keep
rain away from coax connections and all-stainless hardware
ensure maximum durability plus long product life.
The MFJ-2912 mounts on the exterior wall of your building to keep
RF out of the shack and away from internal house wiring. It also
prevents electrical noise generated in the building from migrating
up to the antenna feedpoint and raising your receiver’s noise floor.
The toroid-style transmission-line choke is rated for maximum
legal power on SSB and CW, and it delivers an impressive 30+ dB
of through-transmission (S21) common-mode isolation on 80-10
meters. The exterior wall-mount package also provides a
convenient disconnect point for lightning protection. The MFJ-
2912 uses premium-grade SO-238 connectors that are mounted
on the bottom surface of the enclosure to keep rain away from
coax connections. All-stainless hardware and rugged components
ensure maximum durability plus long product life.
