MFJ 1798 - Page 3

MFJ-1798 Vertical Antenna Instructions
2
A small adjustable "T" section near the bottom allows adjustment of the resonant frequency of
the full size radiating element on 20 meters.
A three section loading coil with capacitance hats for 30, 40, and 80 meters is mounted next to
the 20 meter "T" adjustment near the lower end of the antenna.
The base section contains the air core high power choke balun. This balun uses Teflon insulated
coaxial cable. The base section normally mounts on masts below 1-1/2" diameter, but additional
holes are provided to accept masts up to 2" diameter with user supplied clamps.
10 1500 2500 1250 2.0MHz
6 300 750 300 2.4MHz
2 200 200 200 7MHz
CHOOSING A LOCATION FOR THE ANTENNA
WARNING: Improper installation and assembly can be hazardous! Read these instructions
thoroughly before attempting to assemble, install or operate this product! High power
transmitting devices produce voltages that can cause severe burns or other injuries.
For the best performance on receiving and transmitting, mount this antenna in a clear location at
least a few feet above or 70 feet away from buildings, towers, feedlines, utility wires, and other
antennas. While your own ingenuity and particular circumstances will determine the final
mounting method, we will pass along few rules that can not be neglected.
Never
mount this antenna in a location that will permit unsuspecting people to come in contact
with the loading spokes or any other part of the antenna.
The power rating of this antenna varies from band to band. The PEP ratings are primarily
determined by the voltage breakdown of the components, while the CW ratings are generally
determined by component heating.
The following chart lists the power rating and the 2:1 VSWR bandwidth of this antenna:
Band Power Bandwidth
CW SSB RTTY
80 1000 1500 750 35KHz
40 1250 1500 1000 25KHz
30 1500 1500 1500 370KHz
20 1500 2500 1500 700KHz
17 1500 2500 1500 680KHz
15 1500 2500 1500 800KHz
12 1500 2500 1250 750KHz