Antennacraft ST4 - Manual (Page 2)

ASSEMBLING THE ANTENNA
1. Install the two mount brackets on the support tube us-
ing one 8-32 x 1 /
2
-inch screw, one #8 lockwasher and
one 8-32 nut for each bracket. Do not fully tighten it
yet.
2. Position one bracket at the midpoint of the tube. Posi-
tion the other bracket at the bottom of the tube.
3. Slide one end of the RG-58 coaxial cable with PL-259
connectors through the support tube. Connect the PL-
259 connector to the SO-239 terminal on the apex
assembly.
4. Install the apex assembly into the end of the support
tube and secure it with three 4-40 x
3
/ 16 screws and
lockwashers.
5. Screw one 8-32 nut onto the threaded end of each of
the eight disc element rods.
6. Screw each disc element rod into the holes around
the upper disc of the apex assembly, and hand tight-
en each rod. Rotate each 8-32 nut until it fits snugly
against the disc. Then use a 5 / 16 -inch wrench to tight-
en each nut against the disc surface to secure each
rod.
7. Screw one 8-32 nut onto the threaded end of each of
the eight cone assembly rods.
8. Screw each cone assembly rod into the base of the
cone section of the apex assembly, and hand tight-
en each rod. Next, use a wrench to tighten each nut
against the cone surface to secure each rod.
9. Insert the whip assembly into the top of the coil as-
sembly.
10. Note: Never use a wrench on the black plastic insula-
tor part of the apex assembly.
11. To secure the whip assembly, use the (supplied) allen
wrench to tighten the set screw.
12. Place the two mounting brackets against the chosen
section of the antenna mast, and secure each bracket
with a U-bolt, two ½-inch split lockwashers, and two
1 /
4
-20 hex nuts. When each bracket is in the correct
position, tighten the nuts fully.
13. Use the appropriate mast mounting hardware (not
supplied) to secure the coaxial cable to the antenna
mast, leaving some slack in the cable. Mount the mast
section to your chosen mount, following and instruc-
tions that come with the mount.
14. Route the rest of the cable to your receiver or trans-
mitter. Attach the supplied yellow Danger Label to the
mast at eye level, as a safety reminder.
TUNING THE ANTENNA
1. To ensure your antenna works with a minimum stand-
ing wave ration (SWR) on all channels in the 6-meter
amateur radio band, we allowed extra whip length for
proper tuning.
2. To properly tune your antenna, you need a SWR me-
ter, available at your local electronics store.
3. Connect the SWR meter between the transceiver
and the antenna cable, as described in the meter’s
instructions.
4. Measure the SWR on the lowest and highest chan-
nels.
5. If the SWR reading on the lowest channel is high-
er than that specified in the meter’s instructions,
lengthen the antenna by loosening the set screw
and pulling the whip out of the coil about
1
/ 8 -inch.
If the SWR reading on the highest channel is higher
than that specified in the meter’s instructions, remove
the whip from the coil and cut 1 /
8
-inch from its lower
end. You can cut the whip with a hacksaw or large
wire cutters. You can also use a file to make a small
groove around the whip and then break off the piece.
6. Measure the SWR again and repeat the adjustment, if
necessary. Cut off only 1 /
8
-inch at a time, checking the
s/WR each time.
FREQUENCY CURVES
Mount Bracket
Support Tube
Nut
Lockwasher
Screw
Whip Assembly
Allen Wrench
2
3
Cone Assembly
Rod
Nut
Apex Coil
Assembly
U-Bolt
Support Tube
Nut
Lockwasher
Bracket
Mast
Rod
Support Tube
Apex
Assembly
Nut
Lockwasher
Screw
PL-259 Connector
(not supplied)
SO-239
Terminal