Hy-Gain 18AVT/WB-S User manual

INSTRUCTION
MANUAL ORDER NO. 386S
Model 18 AVT/WB-S Vertical
Radiator, Amateur Antenna
WARNING
Installation of this product near power lines is
dangerous. For your safety, follow the installation
directions.
General
Descri
p
tion The Hy-Gain 18AVT/WB-S is an omnidirectional, self-supporting, vertical
radiator that operates in the 10, 15, 20, 40, and 80 meter amateur bands. The
system will work against earth ground or a resonant radial system when
mounted above ground. You make your own radial system following the
manual, or
y
ou can use the H
y
-Gain 14RMO radial s
y
stem kit.
Performance of the antenna can be optimized for either phone or CW with
either a ground or roof mount. Regardless of the optimization, the VSWR
bandwidths of the antenna are broad enough for the antenna to operate at a
VSWR of 2:1 or less from 10 to 40 meters. The bandwidth for 80 meters is
shar
p
er
,
because the antenna is to
p
loaded.
The 18AVT/WB-S now features stainless steel hardware for all electrical and
most mechanical connections.
Heavy-duty "Hy-Q Traps" give automatic band selection. The Hy-Q traps are
parallel resonant circuits which isolate the various sections of the antenna.
This provides true 1/4-wavelength resonance on all bands. The top hat and
80 meter resonator extend coveraqe to 80 meters by top loadinq.
Electrical
Frequency . ........……....... 80, 40, 20, 15, and 10 meter amateur bands
Input Impedance ..............………………………..............................50 ohms
SWR at Resonance .......……………………............................... less than 2:1
Power Capabilities.............…………………................................ 2 kW PEP'
Lightning Protection ...........…………………............................... DC ground
Input Connector .............. . . . . . . . . . . . . . . . . . . . . . . . : . . . . . . . . . . SO-239
Specifications
Theory of
Operation

Mechanical
Overall Height ..... ..........................………………......... 25' (7.62 m) nominal
Mast ..... : ................... ........……………......... accepts up to 1 5/8" (4.1 cm)
Wind Survival .......……………………............................... 80 mph (129 kmph)
'Maximum
p
ower on 80 meters is 1 kW PEP
NOTE: If the terminals of the input connector are checked with an ohmmeter,
they will show a direct short. This is normal! The matching coil in the antenna
base puts the entire system at DC ground, but presents a perfect 50 ohm
im
p
edance to RF ener
gy
.
A good ground is imperative for any vertical antenna system.
The 18AVT/WB-S can be mounted on the ground, on a rooftop or on a mast.
When mounting the antenna above ground, remember that you must also
install a ground plane radial system. When the antenna-is ground-mounted, a
radial system is usually not needed. But in some areas, where soil surface
conductivity is poor and a good ground cannot be made using the method
shown in Figure 4, you will need to lay out ground radials to improve the
efficiency of your antenna.
If you mount your antenna on a roof and find the roof space is too small for a
radial system, you can droop the radials over the edge of the roof at almost
any angle without seriously changing the performance of the antenna. The
radial system must be insulated from the roof and connected to a good
g
round for li
g
htnin
g
p
rotection.
Read through the manual before beginning assembly. Also, acquaint yourself
with the illustrations by checking the parts as you take them from the carton.
Decide where you will mount your antenna (rooftop or ground) and what mode
of transmission you will use (phone or CW). Take special notice of the
dimensions in Figure 1. The antenna parts must be set to the exact
dimensions given, or it will not operate at peak efficiency. The VSWR charts
will help you decide which dimensions to choose.
WARNING
Isolate the antenna from the reach of children or pets. The antenna
radials are hot with RF proportional to the operating power.
CAUTION
The antenna dimensions must be set either for CW operation on all bands
or phone operation on all bands. It is not possible to mix phone and CW
dimensions to allow operation of some bands on CW and some bands on
phone.
Choosing a Site
Assembly
and
Installation

NOTE: The compression clamps used with this antenna are-used in many
varied applications, so the screw head may or may not contact the
lockwasher or clamp body. Once it is tight, do not force the screw by
tightening it further. To do so may damage both the clamp and tubes. Do not
tighten any of the compression clamps until instructed to do so.
Refer to Figure 1 to assemble the main portion of the
antenna.
Install a 1 1/4" compression clamp (Item No. 16), untightened, over the M1
section (Item No. 9) (the base is attached to it already). Slip the M2 section, 1
1/8" x 26", (Item No. 4) into the top of the M1 and set the M2 at dimension "A",
as shown. Slip the clamp into place around the top of the M1 and tighten it
j
ust enou
g
h to kee
p
the M2 from sli
pp
in
g
.
Install an untightened 1 1/8” compression clamp (Item No. 17) over the M2.
Then slip the 10-meter trap (Item No. 10) bottom-first into the M2 butting it
against the top of the M2. (The top of this trap has a plastic cap on it.)
Slide the clamp into place around the top of the M2 and tighten it just enough
to kee
p
the tra
p
from sli
pp
in
g
.
There are two M3 sections supplied-one for ground mounting, 1 1/8" x 5 7/8"
(Item No. 2) and one for roof mount, 1 1/8" x 9", (item No. 5). Choose the
correct one for your installation and slide it onto the end of the 10-meter trap.
Place a 1 1/8" compression clamp (Item No. 17) around the lower end of the
M3. Then set the M3 at dimension "B" and tighten the clamp just enough to
keep the M3 from slipping.
NOTE: There is a drainage hole in the side of the tube above the trap. Align
this hole with the slot in the M3 to allow
p
ro
p
er draina
g
e.
Install a second, untightened 1 1/8" compression clamp over the M3. Slip the
15meter trap (Item No. 7) into the M3. Set it at dimension "D" and tighten the
clamp just enough to keep it from slipping.
There are two M4 sections supplied-one for ground mount, 11/8" x 14" (Item
No. 36), and one for roof mount, 1 y8" x 12" (Item 37). Choose the correct one
for your installation and slide it onto the end of the 15-meter trap. Place a 1
1/8"compression clamp around the lower end of the M4. Set the M4 at
dimension "E" and tighten the clamp just enough to keep it from slipping.
NOTE: There is a drainage hole in the side of the tube above the trap. Align
this hole with the slot in the M4 to allow
p
ro
p
er draina
g
e.
M4 Section
Assembly
M3
Section
Assembly
M2
Section
Assembly
M1
Section
Assembly

Figure 1 Antenna Assembly
Dimensions

Install a second, untightened 1 1/8" compression clamp (Item No. 17) over
the M4. Slip the 20-meter trap (Item No. 12) bottom-first into the M4. (The top
of this trap is tapered.) Set the trap at dimension "G" slide the clamp into
p
lace, and ti
g
hten it
j
ust enou
g
h to kee
p
the tra
p
from sli
pp
in
g
.
Slide the M5 section, 1 1/8" x 20'/2" (Item No. 1), swaged end up, onto the
end of the 20-meter trap. Place a 1 1/8" compression clamp around the lower
end of the M5. Butt the M5 against the top of the trap and tighten the clamp
just enough to keep the M5 from slipping.
NOTE: There is a drainage hole in the side of the tube above the trap. Align
this hole with the slot in the M5 to allow
p
ro
p
er draina
g
e.
Assemble a 1" compression clamp (Item No. 15) over the swaged end of the
M5. Slide the M6 section, 7/8" x 22 1/2" (Item No. 6), into the M5. Set the M6
at dimension "H" and tighten the compression clamp just enough to keep the
M6 from slipping.
Slide the M7 section, 5/8" x 31" (Item No. 8), insert end up, into the swaged
end of the M6. Drop an untightened 3/4" compression clamp down over the
M7. Set the M7 at dimension "J", slide the clamp around the swaged end of
the M6, and tighten it just enough to keep the M7 from slipping.
Recheck all dimensions and ti
g
hten all the clam
p
s securel
y
in
p
lace.
This com
p
letes this
p
ortion of the antenna. Set it aside to be com
p
leted later.
Refer to Figure 2, Top Assembly Details and Figure 3 in connection with the
following steps:
Push a 1/8" ca
p
lu
g
(
Item No. 20
)
on the end of each to
p
radial
(
Item No.
Attach the four radials to the top plate (Item No. 18) as shown. Set the
radial assembl
y
aside to be used later.
Determine the proper length for your whip rod as indicated in the cutting
chart, Figure 3.
File a deep notch around the rod with a file and snap off as shown in the
detail in Figure 3.
Insert two (2) #8 setscrews (part of Item 11) in the top of the whip fitting
and insert the whip rod 1 inch into the whip fitting and tighten.
Screw a 3/8" - 24 nut
(
Item No. 35
)
onto the bottom of the whi
p
M5 Section
Assembly
M6
Section
Assembly
M7 Section
Assembly
Top Section
Assembly

ROOF MOUNTED BASE DETAILS
. WARNING
When Installing your system, take extreme care to
avoid any accidental contact with power lines or
overhead obstructions. Failure to exercise this care
could result In serious or fatal Inury.

Screw the completed whip assembly into the top -of the white 80-meter
resonator (Item No. 13), as shown in Figure 2. The lower end of the
resonator has a draina
g
e hole. in the side. -
Screw the nut down snu
g
a
g
ainst the resonator.
Thread a 3/8" - 24 x 1" stud (Item No. 25) 3/8" into the insert in the M7
section (Item No. 8). Place radial assembly over the stud as shown in
Figure 2. Install one 3/8" - 24 nut (Item No. 35) on the stud and tighten to
secure radial assembl
y
.
Place 3/8" internal lockwasher (Item No. 34) on 3/8" stud so that the
lockwasher will be between the nut and the 80-meter resonator.
Thread the whip assembly/ resonator (Item Nos. 11 & 13) on the stud and
ti
g
hten hand ti
g
ht.
CAUTION
Figure 3 Cutting Chart for
Whip Rod

Refer to the two mounting details in Figure 2 and Figure 4 to install the
completed antenna.
First mount the completed antenna on your mast (not supplied) as shown in
Figure 2. Use the two (2) 5/16” x 1 5/8" x 2 ¼” U-bolts (Item No. 30). 5/16”
nuts
(
Item No. 32
)
and 5/16" lockwashers
(
Item No. 31
)
.
Use three (3) 1/4" – 20 ¾”bolts, nuts and lockwashers (Item Nos. 26,27 & 28)
to attach the insulator to the u
pp
er end of the mountin
g
bracket.
If you are roof mounting your antenna, use four sets of 1/4”-20 hardware for
the preceding step. Before tightening them, attach two adjacent radials to
each set of hardware as shown in Figures 2 and 4.
NOTE: If your antenna is mounted more than 24" above ground, a radial
system must be added for proper operation. Also, note that the radial system
can serve to
g
u
y
the s
y
stem if insulators are used at the
p
ro
p
er len
g
ths as
.This system must be grounded for lightning protection. Connect a ground wire
to one U-bolt on the antenna base and run it to a buried, 8' ground rod by the
shortest route.
If you are ground mounting your antenna, install it as shown in Figure 2. You
must install an 8'
g
round rod as shown.
AO-0386-A-
40M
Figure 4
Roof Mounting Radials
Installing
the
Antenna

Connect your coax (RG-8/u to the SO-239 connector at the bottom of the
mounting bracket.
Weatherproof all connectors which will be exposed to rain or ice with Coax-
Seal° or another similar substance.
For maximum lightning protection, we recommend the use of a Hy-Gain LA-1
Lightning Arrestor, available from your Hy-Gain dealer.
Your antenna is now read
y
to use.
Figure 5 Completed
Installation
Coax-Seal is a re
g
istered trademark of Universal Electronics
,
Inc.
Hooking Up
the Antenna

Figure 6 Typical VSWR Curves
(
Ground Mount
)
Figure 7
Com
p
ression Clam
p
s
-

1. The antenna operates progressively from 10 through the lowest band
available. Even though you may not be using 10 meters at the present
time, 10 meters must be adjusted, because any adjustment made between
the base and the first trap automatically changes all of the bands at a later
date.
2. Because every antenna installation is influenced by the soil conditions and
the proximity effect of nearby objects, the dimensions in the manual must be
fine tuned to
p
ut the antenna exactl
y
where
y
ou want it on each band.
3. Beginning on 10 meters make a VSWR curve, checking the low end, center
and high end of the band. This will indicate if the antenna favors the low end
or the hi
g
h end as installed.
A. If it favors the low end, shorten the 10-meter adjustment one inch or no
more than 1 ½ inches. Run another VSWR measurement. Now you
will have an indication of how far that distance moved the antenna in
your location. Make what additional adjustments are indicated by the
VSWR curve to put 10 meters exactly on the portion of the band you
desire as
y
our center o
p
eration fre
q
uenc
y
.
B. If the antenna favors the high end, lengthen the dimension
correspondingly to move the antenna to a lower frequency as outlined
above.
4. Next
,
re
p
eat this same
p
rocedure for 15 meters to
p
ut that band on
5. The same procedure is then used to set up the 20-meter band, as well as
the remainin
g
bands available
,
de
p
endin
g
u
p
on the model involved.
6. Most verticals are monopole antennas or half of a dipole. For this reason,
the soil conditions when the antenna is ground mounted are important as it
makes up the other half of the antenna. When you roof mount the antenna,
radials must be used as outlined in the assembly instruction manual to
provide the other half of the antenna.
Convertin
g
En
g
lish Measurements to Metric
Use this scale to identify lengths of bolts, diameters of tubes, etc. The English
inch
(
"
)
and foot
(
'
)
can be converted to centimeters in this wa
y
.
1 inch
(
1"
)
= 2.54 cm
1 foot
(
1 '
)
= 30.48
Example:
Final
Adjustment for
Setting the . _
12AVQ, 14AVQ
and 18AVT

- Parts List
Item
No. Part No. Description Qty
1 170603 Tube, 1 1/8 x 20142" (M5) ...............................………………………. 1
2 170606 Tube, 1 1/8” x 5 7/8” ground mount (M3) .....................…………….. 1
3 170610 Top Radials............................................……………………………….. 4
4 170612 Tube, 1 1/8” x 26"
(
M2
)
...................................……………………….. 1
5 170621 Tube, 1 1/8” x 9", roof mount (M3)..........................………………….. 1
6 170625 Tube, 7/8" x 22 1/2", (M6) ...... ..........................………………………. 1
7 870135 Trap, 15-meter............................................……………………………. 1
8 870136 Top Rod with insert, (M7)................................………………………. 1.
9 870137 Base Assembly, (Ml) ..............................…………………………........ 1
10 870138 Trap, 10-meter.....................................………………………………..... 1
11 878793 Whip Assembly.....................................……………………………….... 1
12 870169 Trap, 20-meter.......................................……………………………..... 1
13 878761 Resonator,80-meter..................................……………………………... 1
872014 Parts Pack 386S,18AVT-S ...........................………………………...... 1
14 165361 Compression Clamp, ¾”. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………………………………... . . . 1
15 168682 Compression Clamp, 1" ............................…………………………...... 1
16 168680 Compression Clamp, 1 ¼”..............................………………………..... 1
17 168681 Compression Clamp, 1 1/8” ...........................…………………………………....... 6
18 170615 Top Plate ........................................…………………………………..... 1
19 351787 Allen Wrench, No. 8............................……………………………........ 1
20 455624 Caplug, 1/8” ", black ............................………………………….......... 4
21 500158 Bolt, hex head, #10-24 x 1/2" ................……………………….............. 5
22 565697 Lockwasher, internal, #10...................………………………….............. 5
23 554071 Nut, hex, #10-24...........................………………………………............. 6
24 555693 Nut, square, #10-24.......................……………………………............... 1.
25 500156 Bolt
,
hex head
,
¼"-20 x 3/8”.. ...............………………………............... 8
26 505266 Bolt, hex head, ¼” – 20 x ¾”………………………..…………………….4
27 562961 Lockwasher, internal, ¼”....................…………………………............... 5
28 554099 Nut, hex, ¼"-20 .........................………………………………................ 4
29 551367 Nut, square, ¼”-20.....................………………………………................ 8
30 543792 U-Bolt
,
5/16” x 1 5/8” x 2 ¼”...............……………………….................. 2
31 564792 Lockwasher, split, 5/16...............…………………………….................. 4
32 555747 Nut, hex, 5/I6"-18...................……………………………....................... 4
33 540037 Stud, 3/8"-24 x 1"................………………………………....... ............... 1
34 565696 Lockwasher, internal, 3/8"...........………………………….. ................... 1
35 552964 Nut, hex, 3/8” -24.. .................…………………………….. .................... 2
36 170271 Tube, 1 1/8”x 14", ground mount (M4) …………………....................... 1
37 170277 Tube, 1 1/8” x.12", roof mount (M4) ....…………………....................... 1