
CW Optimizer
Capacity Hat Kit
for the
75/80 and 80/40
Thunderbolt®
Vertical Antennas
DXE-7580-THK
DXE-7580-THK-INS Revision 2
(US Patent No. 7,002,525)
© DX Engineering 2018
1200 Southeast Ave. - Tallmadge, OH 44278 USA
Phone: (800) 777-0703 ∙ Tech Support and International: (330) 572-3200
Fax: (330) 572-3279 ∙ E-mail: DXEngineering@DXEngineering.com

Introduction
This CW Optimizer Capacity Hat add-on kit is especially designed for the DXE-8040VA-1 80/40
Meter Multi-band and the DXE-7580VA-1 75/80 Meter Monoband high performance DX
Engineering Thunderbolt® vertical antenna systems. This add-on kit allows the center of resonance
to be moved down to the low band edge for dedicated CW operation.
Easy to add to or remove from upper antenna mast with two studded element clamps after lowering
antenna.
The DXE-7580-THK CW Optimizer Capacity Hat Kit may be added to most antenna designs,
including homebrew, to lower the resonant frequency or allow a shorter overall length antenna for
the same frequency. Additional DX Engineering Hot Rodz® are available in different lengths and
experimentation is encouraged!
Features - The DXE-7580-THK consists of:
Precision 6061 T6 Aluminum Threaded Hub (US Patent No. 7,002,525)
Stainless Steel Hub Fastening Hardware
Six Rod Fastening Stainless Steel Set Allen Cup Point Screws
One 5/64" Allen Wrench
Six pre cut 48" Stainless Steel Hot Rodz®
Six Plastic Safety Tips
Custom "L" Bracket for mounting on the vertical antenna
Two 1-1/4" Stainless Steel Studded Band Clamps and stainless steel hardware*
* Additional Studded Band Clamps for a wide range of tube diameters and Hot Rodz® of
different lengths are available from DX Engineering for your specific needs.
Tools Required
Medium size flat blade screwdriver or 5/16" nut driver for the studded element clamps
9/16” open end wrench
5/64” Allen Wrench (included in kit)
Tape measure
Manual Updates
Every effort is made to supply the latest manual revision with each product. Occasionally a manual
will be updated between the time your DX Engineering product is shipped and when you receive it.
Please check the DX Engineering web site (www.dxengineering.com) for the latest revision manual.
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Capacity Hat Assembly and Installation
DXE-7580-THK Capacity Hat
Threaded Hub (US Patent No. 7,002,525)
Top Hat “L” Mounting Bracket
3/8" -24 x 1/2” long Stainless Steel Hex Head Bolt
3/8" -24 x 3/4” long Stainless Steel Hex Head Bolt
3/8” Stainless Steel External Tooth Washer
3/8” Stainless Steel Flat Washer
3/8” Stainless Steel Split Washer
#8-32 x 1/8" long Stainless Steel Allen Screw - Cup Point
Stainless Steel Studded Element Clamp, 1-1/4"
#10 Stainless Steel External Tooth Washer
#10 Stainless Steel Flat Washer
#10 Stainless Steel Split Lock Washer
#10-24 Stainless Steel Nut
Hot Rodz® - 0.125" x 48" Stainless Steel
Plastic End Cap, 0.110" x 1" long
Parts List:
Note: JTL-12555 Jet Lube SS-30 Anti-Seize should be used on all clamps, bolts and stainless
steel threaded hardware to prevent galling and to ensure proper tightening.
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The drawing to the right shows the Capacity Hat parts
for reference.
Also included in this kit is one 5/64" Allen Wrench.
1. Locate the two 1-1/4" studded element clamps, the Top Hat "L" Bracket, two #10 stainless steel
star washers, two #10 stainless steel split washers, two #10 stainless steel washers and two #10
stainless steel hex nuts. Assemble the studded element clamps to the "L" bracket as shown
below.
2. Install the 3/8" -24 x 1/2” long Stainless Steel Hex Head Bolt in the top of the threaded hub.
This bolt is used to hold the hub when tightening the lower bolt in place. Assemble hub to the
“L” bracket as shown using the external tooth washer between the hub and the “L” bracket and
the flat, split washers and 3/8”-24 x 3/4” long hex bolt as shown below.
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3. Lower the antenna and install the "L" bracket to the 1.125" OD element, just above the 1.25"
OD element. Tighten the studded element clamps to hold the assembly in place.
When mounted to either the DXE-8040VA-1 80/40 Meter Multi-band or the DXE-7580VA-1 75/80
Meter monoband high performance DX Engineering Thunderbolt® vertical antenna systems, the
capacity hat is located as shown.
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4. Locate six Allen screws (1/8" long) and install them loosely in the hub as shown below using
the included Allen wrench. These are the Allen Screws that will hold the Hot Rodz® in place
after you adjust their lengths. Insert the Hot Rodz® in the hub as shown below. Slide them in the
hub and adjust their length to be 3 feet. Tighten the appropriate Allen screw to hold them in
place. Refer to the pictures below for reference.
5. Locate and install the six plastic end caps on the ends of the Hot Rodz®.
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Tuning
Hot Rodz®, 48 in. Stainless Steel Rods
Hot Rodz®, 36 in. Stainless Steel Rods
Hot Rodz®, 60 in. Stainless Steel Rods
Hot Rodz®, 72 in. Stainless Steel Rods
Adjust the physical position of the Top Hat
on the 1.125" element tube section to
achieve resonance on your target frequency.
Sliding the Top Hat higher will shift the
point of resonance to a lower frequency.
Sliding the Top Hat lower will shift the
point of resonance to a higher frequency.
The position of the Top Hat Kit rods within
the hub will also affect tuning.
Shortening the rods or removing some of
them will shift the resonant frequency
higher.
Lengthening the rods will shift the resonant frequency lower.
Optional Items
Hot Rodz®, - Stainless Steel Rods
One set of six (in the lengths listed below) stainless steel rods, and plastic safety tips.
Six Stainless Steel rods
Twelve Plastic safety tips
For use with the Hot Rodz® Capacity Hat
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Band Clamp with Stud, 0.500 in OD tube, package of 2
Studded Band Clamp - 0.500" OD tube - Package of 2
Studded Band Clamp - 0.625" OD tube - Package of 2
Studded Band Clamp - 0.750" OD tube - Package of 2
Studded Band Clamp - 0.875" OD tube - Package of 2
Studded Band Clamp - 1.000" OD tube - Package of 2
Studded Band Clamp - 1.125" OD tube - Package of 2
Studded Band Clamp - 1.250" OD tube - Package of 2
Studded Band Clamp - 1.500" OD tube - Package of 2
Studded Band Clamp - 1.750" OD tube - Package of 2
Studded Band Clamp - 2.000" OD tube - Package of 2
Studded Band Clamp - 2.250" OD tube - Package of 2
These clamps are great for mounting items or making connections to a tube or pipe with an outside diameter of 0.500"
to 2.250". Each stainless steel element clamp has a 3/4 inch long, 10-24 stud welded to it, which allows attachments
without drilling holes that could weaken element or tower tubing. Stainless steel attachment hardware consisting of flat
and split-ring lock washers and 10-24 nuts are included. Sold as a package of two.
Technical Support
If you have questions about this product, or if you experience difficulties during the installation, contact DX
Engineering at (330) 572-3200. You can also e-mail us at:
DXEngineering@DXEngineering.com
For best service, please take a few minutes to review this manual before you call.
Warranty
All products manufactured by DX Engineering are warranted to be free from defects in material and workmanship for a period of one (1) year from date of shipment. DX
Engineering’s sole obligation under these warranties shall be to issue credit, repair or replace any item or part thereof which is proved to be other than as warranted; no
allowance shall be made for any labor charges of Buyer for replacement of parts, adjustment or repairs, or any other work, unless such charges are authorized in advance by
DX Engineering. If DX Engineering’s products are claimed to be defective in material or workmanship, DX Engineering shall, upon prompt notice thereof, issue shipping
instructions for return to DX Engineering (transportation-charges prepaid by Buyer). Every such claim for breach of these warranties shall be deemed to be waived by
Buyer unless made in writing. The above warranties shall not extend to any products or parts thereof which have been subjected to any misuse or neglect, damaged by
accident, rendered defective by reason of improper installation, damaged from severe weather including floods, or abnormal environmental conditions such as prolonged
exposure to corrosives or power surges, or by the performance of repairs or alterations outside of our plant, and shall not apply to any goods or parts thereof furnished by
Buyer or acquired from others at Buyer’s specifications. In addition, DX Engineering’s warranties do not extend to other equipment and parts manufactured by others
except to the extent of the original manufacturer’s warranty to DX Engineering. The obligations under the foregoing warranties are limited to the precise terms thereof.
These warranties provide exclusive remedies, expressly in lieu of all other remedies including claims for special or consequential damages. SELLER NEITHER MAKES
NOR ASSUMES ANY OTHER WARRANTY WHATSOEVER, WHETHER EXPRESS, STATUTORY, OR IMPLIED, INCLUDING WARRANTIES OF
MERCHANTABILITY AND FITNESS, AND NO PERSON IS AUTHORIZED TO ASSUME FOR DX ENGINEERING ANY OBLIGATION OR LIABILITY NOT
STRICTLY IN ACCORDANCE WITH THE FOREGOING.
©DX Engineering 2018
DX Engineering®, DXE®, DX Engineering, Inc.®, Hot Rodz®, Maxi-Core®, DX Engineering THUNDERBOLT®, DX Engineering Yagi Mechanical®, EZ-BUILD®,
TELREX®, Gorilla Grip® Stainless Steel Boom Clamps, Butternut®, SkyHawk™, SkyLark™, SecureMount™, OMNI-TILT™, RF-PRO-1B®, AFHD-4® are trademarks of
PDS Electronics, Inc. No license to use or reproduce any of these trademarks or other trademarks is given or implied. All other brands and product names are the
trademarks of their respective owners.
Specifications subject to change without notice.
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