-18-
Install the coax feedline as shown. Make a 10 turn
coil of coax 6 in (15.2 cm) in diameter and tape it to the
boom. This takes place of a balun and keeps RF off
of the feedline and tower. Then tape the feedline to
the boom and mast. Be sure that the coax is not free
to swing in the wind, putting stress on the coax
connector!
INSTALLATION NOTES
The antenna may be installed as a unit atop the mast, or it may be installed one element at a time. Be
sure that the 10/15 meter side of each element is on your right as you face it from the tower. Either way
watch out for POWER LINES, guy wires, or other obstructions that may catch the antenna as it is going
up, causing damage, injury, or even death.
If you am using a small rotor, it must either be used with a thrust bearing or be mounted right under the
boom. A long mast above the rotor will result in damage to the rotor and antenna unless a thrust bearing
is used.
Guy wires must either be out of the immediate field of the antenna, nonconductive, or broken up by
compression insulators into non resonant lengths.
Do not hang dipoles below the beam! They will detune it.
The HF5B like any other 20 meter beam, must be AT LEAST 30 FT (9.1 M) above ground and "in the
clear" to work properly. If you do not heed this instruction, do not be surprised if there are tuning
problems.
CONNECTING THE FEED LINE
1.
The HF5Bshould be fed with any good quality 50 ohm coaxial cable terminated in a PL-259 plug.
2. A 1:1 balun (not included) may be used at the
feed point but is not necessary. If you are not
planning to use a balun, construct an RF choke by
winding about 10 turns of the coax feed line in a 6
inch (15.2 cm) diameter coil, tape the coil
together, and hang it from the boom with tape or
wire. This device will help to keep RF off of the
feed line and tower.
3.
Dress the coax along the boom, down and around
the rotor in a loop loose enough to allow 360
degrees of rotation, and along the tower. Avoid
loose, dangling feed lines, as this can cause tuning
problems.
4. Use the small roll of coax sealer (PP) to cover the
junction of the PL-259 and the SO-239. Do not
place the sealer on the opposite side of the SO-
239 where the wire is soldered.
NOTE: THE COAX BRAID WILL BE AT GROUND
POTENTIAL IF THE ANTENNA IS INSTALLED
ON A GROUNDED SUPPORT! BEFORE
CONNECTING THE COAX TO YOUR
EQUIPMENT, DISCONNECT THE EQUIPMENT
FROM THE AC MAINS TO AVOID SHOCK!
FINAL TUNING
The HF5B is an efficient, short, high-Q circuit. As such, bandwidth tends to be a bit narrow on 20
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