| 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”.
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