Hy-gain DIS-72 Discoverer 7-2 40 Meter 2 Element HF Beam Instruction Manual
- June 2, 2024
- Hy-Gain
Table of Contents
Hy-gain DIS-72 Discoverer 7-2 40 Meter 2 Element HF Beam
Specifications
- Product Name : DIS-72 Discoverer
- Model : 7-2
- Frequency Band : 40 Meters
- Number of Elements : 2
- Optimum Spacing
- Linear-loading design for lower loss and greater radiation efficiency
- Stainless steel hardware and clamps
Product Usage Instructions
Chapter 1 – General Description
This section provides an overview of the product and its key features.
Chapter 2 – Pre-Assembly Information
Prepare for the assembly process by organizing the components and tools needed for setup.
Chapter 3 – Assembly
- Assemble the Boom-to-Mast Brackets and Boom.
- Attach the Element-to-Boom Brackets.
- Install the Driven Element and Reflector Element.
- Connect the Driven Element and Reflector Linear-Loading Wire Assembly.
- Complete the Beta Match Assembly.
Chapter 4 – Installation
Follow the instructions to install the beam, either on a crank-up tower or other suitable structure. Ensure proper attachment and alignment.
Chapter 5 – Service/Parts List
Refer to the provided service information and parts list for maintenance and troubleshooting.
FAQ
- Q: What is the frequency band of the DIS-72 Discoverer?
- A : The DIS-72 Discoverer operates on the 40-meter Amateur band.
- Q: What type of hardware is used in the construction of the Discoverer 7-2?
- A : The Discoverer 7-2 features stainless steel hardware and clamps on all electrical and most mechanical connections for durability.
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.
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 loading 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 degrees @ 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.
CHAPTER 2 -PRE-ASSEMBLY
Preparation for Assembly
FOR OUR OVERSEAS CUSTOMERS:
The United States uses American units of measurement. If you use the Metric System, see “Converting 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 ‘easy assembly of the Discoverer 7-2.
TYPE OF TOOL
- Tape Measure, 12 foot ……
- Adjustable Wrench, 8 inch
- Nut Driver, 7/16 inch …….
- Nut Driver, 3/8
- Nut Driver, 5/16 in Standard Hand
NOTE : When unpacking your antenna, check the 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.
All tubing supplied with the Discoverer 7-2 telescopes together. Make all measurements 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
Corrosion Precautions
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 antioxidant within element tubing assemblies. This prevents aluminum oxide from forming on the aluminum surfaces, especially in coastal environments.
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 clothing
Before assembling the tubing sections, abrade the mating surfaces with a wire brush or sandpaper. Apply the anti-oxidant to both surfaces, then assemble the joint. Wipe off any excess material.
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 !
Penetrox@ is a registered trademark of Burndy Corporation
Cycolac@ is a registered trademark of Borg-Warner
CHAPTER 3
Assembly of the Boom-To-Mast Brackets and Boom
Refer to Figure 1 and begin as Attach the remaining boom sections (Item No. 50
) and secure with the two (2) 1/4″ – 20 x 21/2″ bolts, internal lock washers
and nuts (Item Nos. 53, 32 & 34). Tighten all hardware securely.
Select the boom-to-bracket clamp and casting to-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 lock washers and nuts (Item Nos. 25, 27 and 26
and the four (4) 1/4″ – 20 x 3/4″ bolts, internal lock washers and nuts (Item
Nos 30, 32 and 34).
Element-To-Boom
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.
Assembly of the Driven Element
Select the parts, as listed in Figure 3, and assemble 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 up 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.
Installation of Tubing
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 information. 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 entitled CW, MID, and
PHONE. The CW set 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 lengths shown in Table 1.
Assembly of the Reflector Element
Select the parts listed in Figure 8 and assemble them as shown. Before tightening the hardware, make sure that:
- R1 (Item No. 10) is inserted completely into the element-to-boom brackets.
- R1 (Item No. 10) is positioned with the small holes up and down.
- R1 (Item No. 10) is positioned so that the element will be horizontal when installed on the mast.
- Tighten the anchor bolts (Item No. 28) last. This will ensure that the element will not slip on the boom.
- Refer to Figure 4 for tubing clamp assembly information. Tighten these clamps securely after setting Item Nos 6 & 7 to their proper length.
- Set the length of the RS section (“B”) to one of the lengths in Table 2. The reflector and driven element must both be adjusted to the same setting for proper operation.
DRIVEN ELEMENT
Driven Element and Reflector Linear- loading Wire Assembly
Select the parts listed in Figure 10. Refer to Figures 10, 11, and 12 for assistance in assembling and identification of the linear-loading wire assembly. Start assembling the linear-loading wire section (LLW) to the elements, beginning at the 40-meter insulator.
The 7/8″ tubing clamp (Item 42) as shown in Detail A of Figure 11 should be
positioned as close as possible to the 40 meter insulator. Other clamps and
wire positions will depend upon the final assembly of the linear loading
wires.
Repeat this instruction for each half of the driven and reflector element.
Tighten all bolts securely!
Figure 11 Attachment of Linear-Loading Wire Assembly Near Insulator
Beta Match Assembly
Select the parts listed in Figure 13 and Detail A and assemble them as shown. The beta shorting clamp should be flush with the ends of the beta rods. After attaching your coax cable to the feed point, tighten all hardware securely.
Lightning
For proper lightning protection, you must ground your antenna supporting structure. Grounding will ensure noise-free operation and low SWR. A proper ground consists of a 1/2″ x 8′ copper-clad steel ground rod driven into the ground ap-proximately 12 inches away from the concrete tower base. Connect the tower to the ground rod using #8 copper wire and commercial noncorrosive ground clamps.
Attachment of
Strip your coaxial cable (maximum 7 inches) and install solder lugs (not
supplied) and connect to the driven element as shown in Figure 13. An RF choke
made from 12 turns of RG-213/u coax in a 14 inch diameter circle is
recommended with a split coax feed.
An alternative is to use a Hy-Gain BN-86 or BN-4000 50 ohm balun for easy
connection to your coax cable. “Pigtail” leads of #10 gauge stranded wire 7
inches long should be used from the balun to the tubing clamps.
Use a good quality 50 ohm coaxial transmission lines such as Belden 8214 (foam) or Belden 8237, 8267 or 9251 (solid). Take extra care when soldering connectors to foam dielectric coaxial cable. Weather-proof all connectors, which will be exposed to rain of ice, with Coax-Seal© or another similar substance.
Boom Support Assembly
Select the 2-inch ID boom support clamps (Item No. 62) and the boom support
straps (Item No. 61) and assemble on the boom 100 inches from the center of
the boom-to-mast clamp as shown in Figure 14. Tighten the bolts securely.
Select the 20-foot boom support cable and cut into two equal lengths with a
large pair of wire cutters. Attach one end of each cable to the boom support
straps using the thimbles (Item No. 59) provided. See Figure 14. Attach the
turnbuckles (Item No. 57) to the opposite ends of the cable as shown.
Measure the length of the assembled support cable and turnbuckle as shown. Install the 3/8″ x 2″ bolt, lock washer and nut in each half so that they will be available after the antenna has been hoisted to the top of the tower. Also, tighten the turnbuckles so they will not vibrate loose. Route both cables along the boom and tape near the boom-to-mast bracket so they can be reached after the antenna has been mounted on the tower.
Attach the transmission line to the feed point and tighten the hardware securely. Tape the coax to the boom and mast to ensure good strain relief.
Coax-Seal® is a registered trademark of Universal Electronics, Inc.
CHAPTER 4 – INSTALLATION
Installation
Make sure all tubing clamps and anchor screws are securely tightened. Also, make sure all beta-match hardware is tightened securely and free of corrosion.
IMPORTANT: The Discoverer 7-2 is a fairly large and heavy antenna and
requires some consideration as to how you are going to get it to the top of
the tower. Thoroughly read this section before beginning to install your
antenna.
Installation on a Crank-Up Tower
Crank the tower down completely or as low as it will go, and block all
sections from moving by using a 2″ x 4″ piece of wood or a solid iron bar for
heavier towers. The block should be inserte$ through the lattice structure
before the tower is completely down, then the tower can be cranked down until
the block takes the weight off the winch.
Use a ladder to reach the top of the tower. Never climb the lattice structure
of any Crank-up Tower! Attach the mast to the tower and rotator.(The cast
aluminum boom-to-mast bracket should be installed on the mast as shown in
Figure 15.) Attach a gin pole to the tower to assist in lifting the Discoverer
7-2.
Attach the lifting rope to the balance point of the antenna. The lifting rope should be fed through the gin pole or other pulley arrangement attached to the tower. The other end should be at ground level, available to the ground crew for lifting. Guide ropes may be loosely looped over the boom ends and used by the ground crew to guide the antenna away from the tower and ladder. The guide rope’s two loose ends should be held by the ground crew so that the guide rope can be retrieved.
Attaching the Antenna to the Mast
Assemble the two cast aluminum brackets (Item No. l) on the mast at the
desired height above your tower. Secure the two brackets together using the
two (2) 5/16″-18 x 3″ bolts, lock washers, and nuts (Item Nos. 24, 27, & 26).
You may wish to drill a 5/16″ hole through the cast brackets’ center hole and
through the mast and secure using a 5/16″-18 x 4″ bolt, lock washer, and nut
(Item Nos. 66, 27, & 26). This bolt will prevent the antenna from twisting on
the mast in high winds. See Figure 1.
When the antenna reaches the mast bracket, the four (4) 5″ bolts should be
inserted through the holes in the mast bracket and secured using 5/16″ – 18
lock washers and nuts (Item Nos. 23, 27 and 26). Tighten all bolts securely.
You may wish to use a deep-well socket set to tighten these bolts.
The boom support cables may now be untaped from the boom and attached to the mast. Loosen the turnbuckles and slide the entire assembly up the mast until the boom support wires are straight. Tighten the 3/8″ – 16 bolts securely. Take up any slack in each wire with the turnbuckles, until the boom is level. When taut, tie off the turnbuckles. See Figure 14.
Other Types of
When installing the Discoverer 7-2 on a guyed tower, you may wish to use a different guide system. If you have insulators on your guy wires, you will need to keep the antenna away from the guy wires as well as the tower. You may wish to use two ropes attached to the ground about 15 feet apart. These two ropes can then be used to slide the antenna on as it is also being lifted. The two ropes will need to be far enough from the tower base to allow some sag and still support the antenna away from the guy wires.
This completes your installation. Happy Dx’ing!
WARNING
Installation of this product near power lines is dangerous. For your safety follow the in-structions.
CHAPTER 5 SERVICE /PARTS LIST
Service Information
If you are encounter technical problems and need assistance, you should
contact Hy-Gain Customer Service Department.
All requests, inquires, warranty claims, or for ordering replacement parts, contact:
Hy-Gain
308 Industrial Park Road Starkville, Mississippi 39759 USA
Phone : 662-323-9538
FAX : 662-323-6551
NOTE : Item Numbers may not necessarily be in numerical sequence and may appear more than one time, depending on how often a part is used or identical parts being placed in different parts packs.
Parts List Continued
Converting American Measurements to Metric
Use this scale to identify lengths of bolts, diameters of tubes, etc. The American inch (“) and foot (‘) can be converted to centimeters in this way.
- 1 inch (1″) = 2.54 cm
- 1 foot (1′) = 30.48 cm
- Example : 42″ x 2.54 = 106.7 cm
hy-gain® LIMITED
hy gain Warrants to the original owner of this product, if manufactured by hy gain and purchased from an authorized dealer or directly from hy gain to be free from defects in material and workmanship for a period of 12 months for rotator products and 24 months for antenna products from date of purchase provided the following terms of this warranty are satisfied.
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The purchaser must retain the dated proof-of-purchase (bill of sale, canceled check, credit card or money order receipt, etc.) describing the product to establish the validity of the warranty claim and submit the original or machine reproduction of such proofof-
purchase to hy-gain at the time of warranty service hy-gain shall have the discretion to deny warranty without dated proof-of-purchase. Any evidence of alteration, erasure, or forgery shall be cause to void any and all warranty terms immediately. -
hygain agrees to repair or replace at by gain’s option without charge to the original owner any defective product under warranty, provided the product is returned postage prepaid to hygain with a personal check, cashiers check, or money order for $8.00 covering postage and handling.
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Under no circumstances is hygain liable for consequential damages to person or property by the use of any hygain products.
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Out-of-warranty Service: hygain will repair any out-of-warranty product provided the unit is shipped prepaid. All repaired units will be shipped COD to the owner. Repair charges will be added to the COD fee unless other arrangements are made.
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This warranty is given in lieu of any other warranty expressed or
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hygain reserves the right to make changes or improvements in design or manufacture without incurring any obligation to install such changes upon any of the products previously manufactured.
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All hy-gain products to be serviced in-warranty or out-of-warranty should addressed to hygain, 308 Industrial Park Road, Mississippi 39759, USA and must be accompanied by a letter describing the problem in detail along with a copy of your dated proof-of-purchase.
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This warranty gives you specific rights, and you may also have other rights which vary from state to state.