Hy-Gain DIS-72 User manual

DIS-72 Discoverer
7-2 40-Meter 2-Element
HF Beam
Instruction Manual
Hy-gain
308 Industrial Park Road
Starkville, MS 39759

Please record the following information for your records: Date
of Purchase:
Purchased From Price Paid
Please retain your copy of the Bill-of-Sale for Warranty
claims.

TABLE OF
CHAPTER 1- GENERAL DESCRIPTION......................................................................................
1-1 General Description
.............................................................................................................................. 1-1
CHAPTER 2 - PRE-ASSEMBLY
INFORMATION........................................................................ 2-1 Pre
p
aration for Assembl
y
CHAPTER 3 - ASSEMBLY
.................................................................................................................. 3-1 Assembly of the
Boom-to-Mast Brackets and Boom........................................................................ 3-1 Element-to-
Boom Brackets.................................................................................................................. 3-2
Assembly of the Driven
Element......................................................................................................... 3-2 Tubing
Clamps........................................................................................................................................ 3-4
Assembly of the Reflector Element
.................................................................................................... 3-5 Driven Element and Reflector
Linear-Loading Wire Assembly.....................................................3-8 Beta Match Assembly
......................................................................................................................... 3-11 Lightning
CHAPTER 4 - INSTALLATION
..........................................................................................................4-1
Installation.........................................................................................................................................
.......4-1 Installation on a Crank-Up
Tower 4-1 Attaching the
CHAPTER 5 - SERVICE/PARTS
LIST.............................................................................................. 5-1 Service Information
................................................................................................................................5-1 Parts
List 5

LIST OF
Figure Pag
e
1 Assembly of Boom Tubes to Casting-to-Boom Bracket
and Boom-to-Bracket
Clamp........................................................................................ 3-1 2 Element-to-
Boom Brackets ............................................................................................. 3-2 3
Assembly of the Driven Element
.................................................................................... 3-3
4 Tubing Clamps
................................................................................................................... 3-4
5VSWR
Charts..................................................................................................................... 3-4
6 Front-to-Back Charts
........................................................................................................ 3-5

CHAPTER I - GENERAL INFORMATION
General Description
The Hy-Gain Discoverer 7-2 is an optimum spaced,
two element beam for the 40 Meter Amateur band.
The Discoverer 7-2 incorporates the principles of
linear-loading which results in lower loss and
greater radiation efficiency than is possible with
loadin
g
coils.
The Discoverer 7-2 features stainless steel
hardware and clamps on all electrical and most
mechanical connections.
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 injury.
SPECIFICATIONS
Mechanical
Total Number of
Elements........................................................................................................................2
Maximum Element Length ...................................................................................44.8 ft. (13.7 m)
Boom Length..........................................................................................................22.6 ft. (6.9 m)
Boom Diameter.........................................................................................................2 in. (51 mm)
Turning Radius ........................................................................................................25.0 ft (7.6 m)
Accepts Mast ............................................................................. ..........1.625 - 2.5 in. (41-64 mm)
Maximum Wind Survival ...... ......................................................................80 mph (128.7 kmph)
Wind Surface Area.......................................................................................6.0 sq. ft. (0.56 sq. m)
Effective Moment*............................. ......................................................1412 ft.-lb. (192 kg-m)
Wind Load at 80 mph ..........................................................................................................154
Hardware.............................................................................................stainless steel hardware
and clam
Suitable Rotors.....................................................................................................Hy
-
Gain Ham
Electrical
Maximum Gain.......... ............................................................................f)J dBi (4.3 dBd)
Front-to-BackRatio(maximum)…………...............................................................................15 dB
Number of Settings................................................................................................................... 3
Band Width
10 dB Front-to-Back..............................................................................................70 - 90 KHz 3:1
VSWR...............................................................................................................275 KHz @ 60 ft.
2:1 VSWR..........................................................................................................187 KHz @ 60 ft.
VSWR at Resonance ..............................................................................................less than 1.2
Nominal Impedance...................................................................................................50 ohms
Lightning Protection.......................................................................................... DC ground -3 dB
Beam Width ........................................................................77 de
g
rees @ maximum Front-to-
*Effective Moment is defined as the product of the weight of the antenna and the turning radius.
This figure should be used when selecting, an appropriate rotator.
1
-
1/1
-
2Blank

CHAPTER 2
-
PRE
-
ASSEMBLY
Pre
p
aration for Assembl
y
Corrosion Precautions
FOR OUR OVERSEAS CUSTOMERS:
The United States uses American units of
measurement. If you use the Metric System, see
"Convertin
g
American Measurements to Metric"
Choose a large clear area to assemble your
antenna. The area must be at least 23' x 45' (7m x
14m). If you assemble this antenna over a grassy
area, precaution should be taken so that
hardware is not accidentally lost during
assembly. A concrete driveway is an excellent
area for assembly.
TOOLS: The following tools are required for
'eas
y
assembl
y
of the Discoverer 7-2.
The Discoverer 7-2 antenna is designed to be
relatively maintenance free for most
environments. All hardware is made of passivated
stainless steel, typically grade 304. The internal
tooth-type lockwashers used in this antenna are
grade 410 stainless steel, and are slightly
magnetic. The element tubing clamps are grade
304 stainless steel. Most other metallic parts are
aluminum. All insulators exposed to sunlight are
made from U.V resistant black polyethylene or
black Cycolac®.
We have supplied a 3 oz. tube of Penetrox®A-3
from Burndy Corporation for use as an anti-
oxidant within element tubing assemblies. This
prevents aluminum oxide from forming on the
aluminum surfaces, especially in coastal
environments.
TYPE OF TOOL
Tape Measure, 12 foot ......
Ad
j
ustable Wrench
,
8 inch
Nut Driver, 7/16 inch .......
Nut Driver, 3/8
Nut Driver, 5/16 in
Standard Hand
Cut the cap off the tube of Penetrox®A-3. Have
some rags available to clean off excess from
tubing and hands. Be careful not to get this on
your clothin
g
.
Before assembling the tubing sections, abrade
the mating surfaces with a wire brush or
sandpaper. Apply the anti-oxidant to both
surfaces, then assemble joint. Wipe off any excess
material.
NOTE: When unpacking your antenna,
check inside of all tubing for parts
(smaller tubing etc.). To conserve
space these smaller articles are
sometimes put inside larger pieces.
Check all parts against the Parts List to
make sure no parts are missing.
A light amount of clear lacquer or an acrylic spray
may be used to coat the exterior surface of the
element assemblies if this antenna is to be
installed near a sea coast. Tighten all joints
securely before coating !
All tubing supplied with the Discoverer 7-2 tele-
scopes together. Make all measurement to the
given dimensions, plus or minus (+/-), no more
than 1/8 inch! The assembly of this antenna will
be easier if you read this manual completely
through at least twice before beginning
assembly. Allow at least 6 hours for assembly.
Double and triple check ALL dimensions after
assembly. Penetrox@ is a registered trademark of Burndy Corporation
Cycolac@ is a registered trademark of Borg-Warner
2
-
1/2
-
2Blank

C
HAPTER
3
-
Assembly of the Boom-To-Mast Brackets
and Boom
Refer to Fi
g
ure 1 and be
g
in as
Attach the remaining boom sections (Item No.
50 ) and secure with the two (2) 1/4" - 20 x
21/2" bolts, internal lockwashers and nuts (Item
Nos. 53, 32 & 34). Tighten all hardware
securely.
Select the boom-to-bracket clamp and castingto-boom
bracket (Item Nos. 2 and 3) and loosely assemble them on
the boom sections (Item No. 51) with the two 5/16"-18 x
2 3/4" bolts, split lockwashers and nuts (Item Nos. 25, 27
and 26 and the four (4) 1/4" - 20 x 3/4" bolts, internal
lockwashers and nuts (Item Nos 30, 32 and 34).
Item
Item
No. Description No. Description
2Bracket
,
Castin
g
-to-Boom 32 Lockwasher
,
internal
,
1/4" - 20
3Clam
p,
Boom-to-Bracket 34 Nut
,
hex
,
1/4" - 20
25. Bolt, hex head, 5/16"-18 x 2 3/4" 50 Tube, Boom, 2" x 83" 83"
26 Nut
,
hex
,
5/16" -18 51 Tube
,
Boom
,
2" x 54 3/4"
,
27 Lockwasher, split, 5/16" 53 Bolt, hex head, 1/4" - 20 x 21/2"
30 Bolt
,
hex head
,
1/4!' - 20 x 3/4"
Figure 1 Assembly of Boom Tubes to Casting-to-
Boom Bracket and Boom-to-Bracket Clamp

Element
-
To
-
Boom
Assembl
y
of the Driven Element
To save time, loosely assemble both of the ele-
ment-to-boom brackets and their appropriate
hardware before beginning further
installation of the antenna. See Figure 2. The
different sized brackets can be identified by a
number stamped into the surface of each
bracket half. DO NOT tighten the bolts until
instructed to do so.
Slide each assembled bracket over each boom
end. Position the center of each bracket 3
inches from the boom ends. DO NOT tighten
at this time.
Select the parts, as listed in Figure 3, and as-
semble them as shown. Before tightening the
hardware
,
make sure that:
DE1(Item No. 10) is inserted completely
into the driven element insulator.
DE1 (Item No. 10) is positioned with the
small holes u
p
and down.
DE1(Item No. 10) is positioned at 90
degrees from the boom-to-mast bracket, so
that the element will be horizontal when
installed on the mast.
NOTE: ASSEMBLY HARDWARE FOR THE
DRIVEN ELEMENT BRACKET IS THE SAME AS
USED ON THE REFLECTOR BRACKET.
AO
-
372S
-
B
-
007
DRIVEN ELEMENT DETAIL
REFLECTOR DETAIL
Item
No.
4 17
28
30
32
33
34
48
Description
Bracket, Element-to-Boom, #14 "
Insulator, Element, DE1
Bolt, hex head, 1/4"--20 x
3/8" Bolt, hex head, 1/4"--20
x 3/4" Lockwasher, internal,
1/4"-20 Nut, square, 1/4"--
20
Nut, hex, 1/4"--20
Figure 2 Element-to-
Boom Brackets
3-2

Tighten the anchor bolts on the element-to-
boom bracket (Item No. 28) last. This will en-
sure that the element will not slip on the
boom.
AO
-
372S
-
B
-
4
Item
No. Description
7 Tube, Element, DE4 and R4, 5/8" x 26"
8 Tube, Element, DE3 and R3, 7/8" x 55"
9 Tube, Element, DE2 and R2,1" and 51"
10 Tube, Element, DE1 and R1, 11/4" x 83"
16 Insulator, Element, 40 Meter
17 Insulator, Element, DEl
29 Bolt, hex head, 1/4!'- 20 x 11/2"
32 Lockwasher, internal, 1/4" - 20
34 Nut, hex, 1/4" - 20
35 Bolt, hex head, #10 - 24 x 2"
38 Nut, hex, #10 - 24
40 Lockwasher, internal, #10
43 Tubing Clamp
45 Caplug, black, 2"
46 Caplug, black, 7/16"
49 Tube, Element, DE5, 7/16" x 58"
50 Tube, Boom, 2" x 83"
1
5
0
1
"A" Dimension One Half DE I-ngth*
Setting (Inches) (mm) (Inches) (m)
Cw 47 1194 258 6.553
MID 44 1118 255 6.478
PHONE [phone]
*Measured from boom edge to element tip.
Figure 3 Assembly of the
Driven Element
29
-
32
-
3
-

Installation of Tubin
g
Select the #6 tubing clamp as shown in the
chart. When installing the clamp, place the
clamp near the tube end with the top of the
clamp over the slot in the tube as shown in
Figure 4.
After adjustment of the tubing lengths, tighten
the clamp with a 5/16 inch nut driver, socket,
or open end wrench until the tubing will not
twist or telescope.
Refer to Figure 4 for tubing clamp assembly in-
formation. Tighten these clamps securely after
setting Item Nos. 7 and 49 to their proper
length.
The Discoverer 7-2 is supplied with dimensions
for three (3) settings within the 40 Meter
Amateur band. The three (3) settings are en-
titled CW, MID, and PHONE. The CW setting
is optimized for operation from 7.00-7.15 MHz.
The MID setting is optimized for operation
from 7.05-7.25 MHz and the PHONE setting is
optimized for operation from 7.15-7.30 MHz.
The VSWR, Front-to-Back Ratio, and Gain
curves are shown in Figures 5, 6, and 7. From
this information, choose one of the three
settings to use.
Set the length of the DE5 section A to one of the
len
g
ths shown in Table 1.