The MFJ-1778M antenna is a multi-band center-fed dipole antenna capable of 1500 Watts. It consists of 52 feet flat-top fed with 17 feet of 450 Ohm matching section ending in an SO-239 coax connector.

This antenna generally requires the use of a suitable matching network (antenna tuner) since the SWR of the G5RV JR. is almost certainly not 1:1 on any band. The use of a tuner will guarantee maximum performance from solid-state exciters.

MFJ-1778M is a balanced antenna that is fed by an unbalanced coaxial line. This feed system causes unwanted parallel RF currents to appear on the shield of the coaxial feedline.

A choke type balun such as the MFJ-915 should be used with this antenna to eliminate or reduce the undesirable parallel feed line currents. Failure to use a choke balun may result in RFI, RF feedback, or other symptoms of RF "in the
shack".