MFJ MFJ-1770 User manual

MFJ PORTABLE FOLDED DIPOLE ANTENNA
MODEL NO. BAND COVERAGE
MFJ-1770 15 Meter
MFJ-1771 17 Meter
MFJ-1772 20 Meter
MFJ-1773 30 Meter
MFJ-1774 40 Meter
MFJ-1776 6 Meter
GENERAL DESCRIPTION
The antenna is a no-compromise full-size folded dipole antenna designed to give your QRP
station real on-air "punch". Fabricated almost entirely from tough 300-Ohm twinlead, this
antenna is lightweight, easy to transport, and simple to erect. Best of all, you'll never need an
antenna tuner; a 50 Ohm matching network is built right into the antenna's feed system. A
random length of 50 Ohm coax from your rig to the end of the antenna feed can be added if you
need more feedline.
INSTALLATION
This antenna is very light in weight; inexpensive nylon "sash" cord is all you need to support it.
Simply tie your end-lines through the end-holes provided in the antenna's twinlead insulation.
Do not use conductive wire for end-lines this will detune the antenna.
For best results, find supports that are high and in the clear. If you have a choice, run your end-
line over the crown of a tree rather than attaching it to a low branch. If you have only one high
support, set the antenna up as a sloper or inverted "V".
Run the feedline at a right angle to the antenna for at least 30'. Avoid running the balanced
portion of your feedline (the 300-Ohm flat line) next to your tower or other metal structures. This
may detune the antenna and degrade efficiency. Use coax for feedline runs inside your house.
Although designed for QRP rigs, the antenna will handle full RF output from a 100-Watt
transceiver (do not exceed 100 Watts).
WARNING:Constructing or erecting amateur radio antennas in locations where they may come
into contact with electrical power may result in accidental injury or death.

BAND LENGTH A LENGTH B LENGTH C LENGTH D Cs
6 Meter 9' 1" 7' 7.25" 11.5" 7' 7.5" 22pF
15 Meter 22' 0.5" 18' 6.50" 2' 3.5" 26' 8.5" 51pF
17 Meter 25' 10" 21' 8.75" 2' 8.5" 26' 3.5" 60pF
20 Meter 33' 0.0" 27' 9.25" 3' 5.5" 25' 6.5" 75pF
30 Meter 46' 2.5" 38' 10.5" 4' 10" 24' 2.0" 107pF
40 Meter 65' 5.5" 55' 0.5" 6' 10" 22' 2.0" 151pF