DX Engineering THUNDERBOLT DXE-MBVA-1UP User manual

DX Engineering
THUNDERBOLT™
160-10 Meter
Vertical Antenna
DXE-MBVA-1UP
DXE-MBVA-1UP-INS Revision 3
© DX Engineering 2012
P.O. Box 1491 ∙ Akron, OH 44309-1491 USA
Phone: [phone] ∙ Tech Support and International: [phone]
Fax: [phone] ∙ E-mail: [email protected]

- 1 -
Table of Contents
Introduction
2
Features
2
Supplied Installation Items
2
Additional Material Needed, Not Supplied
3
DXE-MBVA-1UP Parts List
4
Manual Updates
4
Suggested Parts Not Included
4
Tools Required
5
Warning
5
Installation
6
Site Selection
6
Radial System
6
Mounting Pipe
7
Assembly
7
Radial Plate to Mounting Pipe
8
Attaching Ground Radial Wires to the Radial Plate
9
Tilt Base to Mounting Pipe
10
Vertical Base Section
11
Base Section to Tilt Base
13
Assembling the Vertical Sections
14
Mating the Vertical Sections to the Tilt Base
18
Raising The Vertical
18
Assembling the UNUN Mounting Bracket
19
Installation of UNUN Assembly to Antenna
20
Feedline Connections
22
Coaxial Cable and 160 Meter Notes
23
Tuning the Vertical
26
Guying a Vertical Antenna System
27
Optional Accessory Items
28
Technical Support and Warranty
31

- 2 -
Introduction
The DX Engineering THUNDERBOLT™ MBVA-1UP is a high performance 160-10 meter
vertical multi-band antenna that is tunable to operate with an SWR of 1.5:1 or less. Designed with
6063 corrosion-resistant aluminum tubing and stainless steel hardware, this antenna is very durable,
attractive, and is an optimized height of only 43 feet!
DX Engineering THUNDERBOLT™ technology has been proven in the hostile, remote
environment of Antarctica’s Peter I Island by the outstanding performance by the 3Y0X DXpedition
with an amazing 5,869 QSOs on 80 meters!
Of course, another key to performance is a good ground radial system. 32 radials, 65 feet long are
recommended. Fewer radials will work, but with diminished results.
The MBVA-1UP 160-10 meter vertical antenna includes the antenna element, mounting plates,
patented Tilt Base, Multi-Band UNUN, patented UNUN Mounting Bracket, stainless steel hardware
and clamps.
Features
Full band coverage on 160-10 meters with an SWR under 1.5:1*
* Customer supplied wide band tuner required.
Power Handling up to 5 kW
Only 43 ft. overall height
Supplied Installation Items:
Tilt Base - Precision laser cut from 3/16 in. 304 Stainless Steel, this patented tilt mounting plate is
virtually indestructible. Mounts to the same mast that you use for the radial plate. Allows for easy
installation, tuning or severe weather lay-down.
DXE-UN-43 - Multi-Band UNUN for Vertical Antenna Systems
The DXE-UN-43 DX Engineering Multi-Band Vertical UNUN built with proven Maxi-Core®
Technology is a matching device specifically designed for application with non-resonant 43
foot tall vertical multi-band antennas.
The DXE-UN-43 assures the best efficiency from your vertical multi-band antenna and
transmission line/tuner installation. Using the DXE-UN-43 results in minimizing the additional
transmission lines losses caused by SWR and allows your antenna to perform to its full
potential. The DXE-UN-43 reduces the stresses on your equipment more efficiently than similar
competitive products.
By allowing your wide-range tuner to more easily match the antenna’s complex impedance, low
frequency performance is improved over other devices currently available.

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DXE-UN-43 Features
Full band coverage on 160-10 meters with an SWR under 1.5:1*
*Customer supplied wide band tuner required.
Impedance: 200 ohms to 50 ohms - optimized for 43 ft. verticals
Ratio: 4:1
Power Handling: 2 KW/5 KW Peak - Handles rated power with minimal energy loss so
there is no thermal related failure.
Silver/Teflon®SO-239 input connector
Two 1/4-20 feedpoint connection studs with Stainless Steel Flat Washers, Split Washers,
Fender Washers & Wing Nuts
High impact plastic, weather sealed NEMA spec case: 2-1/2" x 4" x 4" inches (HxWxL)
Shares the same mounting footprint as other similar competitive products, so it may be
easily substituted in existing installations for superior performance.
DXE-UN-BRKT - Mounting Bracket Kit for the DXE-UN-43 UNUN
Custom patented (US Patent No. D597,086) Mounting Bracket including Custom Stainless Steel 90
degree Studded Element Clamps, Aluminum Spacers and Stainless Steel Hardware for mounting the
DXE-UN-43 to the DXE Multi-Band Vertical Antenna series.
Parts List for the DXE-UN-BRKT
Qty
Description
1
Patented Mounting Bracket for the DXE-UN-43
4
# 6 x 3/4" long Stainless Steel Hex Head Bolts
8
# 6 Flat Washer
4
# 6 Nyloc Nut
2
Custom Stainless Steel 90 degree studded Element Clamp
2
1/8" thick x 5/16" OD Aluminum Spacer for #10 Hardware
2
# 10 Nyloc Nut
DXE-TCB-UNFK - Feed Point Connection Kit
Two 1" wide x 9" long pre-drilled tinned copper braids for feedpoint connection to the vertical
antenna system.
Additional Material Needed but not Supplied:
Antenna Mounting - Steel mounting pipe, up to 2.0″OD, 0.25″wall thickness, 4 feet long.
The standard 1-1/2" galvanized water pipe (with its 1.9" OD) is just fine for this application
and can usually be found at your local home building supply store.
Quik-Set Concrete - Mounting pipe installation (type depends on your landscape)
DXE-P8A - Penetrox™ A - To ensure good connection for aluminum element sections
UMI-81343 - Anti-Seize compound - used on the threads of Stainless Steel Hardware to
prevent galling and aid in proper tightening torque.
Guy Rope and Anchors –DXE-GUY200-KIT contains 4 screw-in earth anchors and two
100 foot rolls of Dacron/polyester rope.

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Parts List for the DXE-MBVA-1UP
Lower Tilt Base Assembly (patented)
Qty
Antenna Assembly:
Qty
Tilt Base, 3/16" Laser Cut Stainless Steel
1
2.00 x 0.125" x 36" Tube. 6063-T632 mat'l.
1
DXE-SSVC-2P Stainless Steel V-Clamp
2
2.125" x 0.058" x 72" Tube. (Slit both ends)
1
Insulated Mast Mount Channel
1
2.00" x 0.058" x 72" Tube. (Slit one end)
1
Mast Mount Backing Plate
1
1.875" x 0.058" x 72" Tube. (Slit one end)
1
1/4-20 x 2" HH Bolt, full thread
4
1.750" x 0.058" x 72" Tube. (Slit one end)
1
1/4" Flat Washer
4
1.625" x 0.058" x 72" Tube. (Slit one end)
1
1/4" Split Washer
4
1.500" x 0.058" x 72" Tube. (Slit one end)
1
1/4" Aluminum Spacer
4
1.500" x 0.058" x 72" Tube. (Slit both ends)
1
1/4-20 Hex nut
4
1.375" x 0.058" x 8" Tube. (Plain)
1
1/4" Fender Washer, 1" OD
4
DXE-ECL-16SS Element Clamp
2
1/4-20 Flanged Nut
2
DXE-ECL-20SS Element Clamp
2
1/4-20 Nyloc nut
4
DXE-ECL-24SS Element Clamp
2
3/8 U-Bolt x 2" ID x 3.25" leg w/ Saddle & Hardware
2
DXE-ECL-28SS Element Clamp
2
Black Vinyl Cap
1
Feedline Connection
Qty
1/4-20 x 1" HH Bolt, full thread.
1
1/4" External Tooth Washer.
2
1/4" Flat Washer.
2
1/4-20 Hex nut.
2
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.
Suggested Parts Not Included
DXE-RADP-3 Radial Plate (patented):
Made from Laser Cut Stainless Steel with 20 Sets of Stainless Steel Radial
Attachment Hardware. The DX Engineering Radial Plate is meant for those of you
having a vertical antenna and want an easy, neat and effective way to connect those
essential radial wires to your antenna system for the highest efficiency and strongest
signals.
DXE-SSVC-2P Stainless Steel V-Clamp:
One required for mounting the optional DXE-RADP-3 Radial Plate to the antenna
mounting pipe of 1" to 2" outside diameter.

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DXE-RADW Radial Wire Kits and Components:
There are optional DX Engineering Radial Wire Kits available. DXE-RADW-500K/BD contains a
500 foot spool of 14 gauge copper stranded wire with black PVC insulation, 20 Terminal Lugs and
100 Steel or Biodegradable Lawn Staples. The DXE-RADW-1000K/BD Radial Wire Kit contains
a 1,000 foot spool of 14 gauge copper stranded wire with black PVC insulation, 40 Terminal Lugs
and 200 Steel or Biodegradable Lawn Staples. RADW-20RT, -32RT or -65RT contain 20 each
radial wires with 1/4" terminal attached. These kits come in 20 Ft, 32 Ft, or 65 Ft lengths.
DXE-GUY-200 Guying Kit for Vertical Antennas:
Some vertical manufacturers indicate their antennas do not need guying. During times
of high winds or ice loading, some of these verticals may sustain damage or fail
altogether. With the small amount of effort needed to install a four point guying system,
the risk hardly seems worth taking. A four-point guying scheme provides the best
mechanical advantage to reduce wind stress, regardless of direction. A four point
guying system is recommended for use with the DX Engineering Tilt Base, because just
one of the guy ropes has to be loosened when you tilt the vertical down. The remaining
guys help stabilize the vertical in three directions when being raised.
Tools Required
Two 7/16”wrenches, (one of them should be open-end)
5/16”, 3/8”, 7/16”, and 1/2”wrenches or
5/16”, 3/8”, 7/16”, and 1/2”sockets and drive
Medium size flat blade screwdriver or 5/16”nut driver for the element clamps
Tape measure
Felt-tip marker
WARNING!
INSTALLATION OF ANY ANTENNA NEAR POWER LINES IS DANGEROUS
Warning:Do not locate the antenna near overhead power lines or other electric light or power
circuits, or where it can come into contact with such circuits. When installing the antenna, take
extreme care not to come into contact with such circuits, because they may cause serious injury or
death.
Overhead Power Line Safety
Before you begin working, check carefully for overhead power lines in the area you will be
working. Don't assume that wires are telephone or cable lines: check with your electric utility for
advice. Although overhead power lines may appear to be insulated, often these coverings are
intended only to protect metal wires from weather conditions and may not protect you from electric
shock

- 6 -
Keep your distance! Remember the 10-foot rule: When carrying and using ladders and other long
tools, keep them at least 10 feet away from all overhead lines - including any lines from the power
pole to your home.
Installation
Site Selection
Select a mounting location clear from power lines, structures and other antennas by a minimum of
55 feet. Consider overhead power lines, utility cables and wires. The vertical should mounted
away from local noise sources or other metallic objects which can re-radiate noise and affect the
tuning, radiation pattern and SWR. Determine the direction you want the antenna to tilt down and
make sure there is adequate clearance (at least 55 feet). There should also be a clear diameter of 65
to 130 feet from the antenna for the guying and radial systems that will extend away from the
antenna.
Radial System
The use of a radial system is a key requirement for a high performance quarter wave vertical
antenna system. With a vertical antenna system, the radials are the second half of the antenna. The
radials contribute to the radiation efficiency of the entire vertical antenna system.
At a minimum, 20 radials, each 32 feet long, should be used with this antenna. Using 32 radials at
65 feet long is preferred and highly recommended. The extra
radials help overcome unknown poor-soil conditions, improve
bandwidth, and ensure the best performance possible from the
vertical antenna. DXE-RADW Radial Wire, a 14 gauge stranded
copper with black relaxed PVC insulation wire is suggested for the
best results.
The wire radials should placed as symmetrically as possible
straight from the feedpoint around the vertical antenna and spaced
evenly, regardless of how many radials are used. Do not cross or
bunch any radial wires as this nullifies their effectiveness. If you
have limited space, put in as many straight radials as you can. The
radials must be connected to the shield of your feedline. The
DXE-RADP-3 Stainless Steel Radial Plate is an ideal optional item which provides an excellent
system for attaching radial wires to your vertical antenna system feedpoint.
Radial wires can be laid on the roots of the grass using DXE-STPL Radial Wire Anchor Pins to
hold them down. Using enough staples will ensure the wires will not be snagged by mowers,
people, or animals. Grass will quickly overgrow the radials and it will be virtually impossible to see
them. An article describing this process is available on the DX Engineering website. Radials can
also be buried just under the surface by using a power edger to make a slit in the soil.

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Mounting Pipe
Use a customer supplied thick-walled galvanized steel mounting pipe at
least 4 feet long. This will allow approximately 2 feet or more to be below
ground and 20 inches above ground. A thick-walled steel pipe 1-3/4" OD
to 2" OD maximum is recommended with a minimum thickness of 1/8"
(1/4" preferred) should be used. The standard 1-1/2" galvanized water
pipe (with its 1.9" OD) is just fine for this application and can usually be
found at your local home building supply store. For permanent mounting,
use a post-hole digger to make the hole deep enough to accommodate at
least 2 feet of pipe and a couple inches of gravel at the bottom for
drainage. Set the mounting pipe on the gravel, use the pre-mix concrete to
fill around the pipe, adding water and mixing as you fill or mix the
concrete first, then pour in the hole (depends on the type of concrete you
purchase). Fill the hole until the concrete is level with the ground around
it. Use a level on the mounting pipe as you fill the hole to be sure is
vertically straight. Allow to set overnight. Your location, landscape and
ground conditions may require different mounting solutions in order to
have the steel mounting pipe and the vertical antenna in a secure position.
Note: Galvanized steel, rather than aluminum, is much more suitable
for mounting in concrete. Aluminum will quickly corrode due to incompatibility with the
materials used to make concrete.
Assembly
The DXE-MBVA-1UP shipping boxes contain the vertical tubing sections, an insulated U-channel,
two 3/8" U-Bolts, saddles with hardware, a backing plate, a Tilt Base, UNUN, UNUN Mounting
Bracket, stainless steel element clamps, a black vinyl cap, and stainless steel hardware.
Carefully un-box the antenna and separate the various parts.
Note: DXE-P8A Penetrox™A Anti-Oxidant should be used between all antenna element
sections. Penetrox™ A is an electrical joint compound to affect a substantial electrical
connection between metal parts such as telescoping aluminum tubing or other antenna
pieces. It ensures high conductivity at all voltage levels by displacing moisture and
preventing corrosion or oxidation.
Note: UMI-81343 Never-Seez® or DXE-NSBT8 Anti-Seize should be used on all clamps,
bolts and stainless steel threaded hardware to prevent galling and to ensure proper
tightening.

- 8 -
Note: The following assembly instructions are based on using a 2" OD Mounting
Pipe, with the optional DXE-RADP-3 Radial Plate.
Radial Plate to Mounting Pipe
Install the optional DXE-RADP-3 Radial Plate on the 2" customer supplied mounting pipe using an
optional DXE-SSVC-2P Stainless Steel V-Clamp as shown in Figure 1. The standard 1-1/2"
galvanized water pipe (with its 1.9" OD) is just fine for this application and can usually be found at
your local home building supply store. Mount the Radial Plate so you have approximately 1" of
space between the bottom of the plate and the ground level. This will allow easy access to install
the radial wire hardware. The DXE-RADP-3 Radial Plate comes with 20 sets of stainless steel
hardware for mounting the radial wires. Mount the plate as shown in relation to how the Tilt Base
is mounted. (For reference, Figure 7 shows the completed installation.)
Figure - 1 - DXE-RADP-3
Radial Plate Installation

- 9 -
Attaching Ground Radial Wires to the Radial Plate
Using the 20 sets of supplied 1/4" stainless steel hardware (Bolt, Flat Washer, Star Washer, Split
Washer, Nut) connect the optional ground radial wires to the DXE-RADP-3 Radial Plate as shown
in Figure 2. Additional hardware kits are available (DXE-RADP-1HWK) that contain 20 sets of
Radial Plate Hardware.
There are optional DX Engineering Radial Wire Kits available. DXE-RADW-500K/BD contains a
500 foot spool of 14 gauge copper stranded wire with black PVC insulation, 20 Terminal Lugs and
100 Steel or Biodegradable Lawn Staples. The DXE-RADW-1000K/BD Radial Wire Kit contains
a 1,000 foot spool of 14 gauge copper stranded wire with black PVC insulation, 40 Terminal Lugs
and 200 Steel or Biodegradable Lawn Staples. RADW-20RT, -32RT or -65RT contain 20 each
radial wires with 1/4" terminal attached. These kits come in 20 Ft, 32 Ft, or 65 Ft lengths.
Depending on the number of radial wires used, space them out evenly around the Radial Plate. The
Radial Plate will accommodate up to 60 radial wires (60 laser drilled holes), or up to 120 radials if
doubled up.
Radial Wire Pattern
Figure - 2 - Radial Wire Hardware Installation

- 10 -
Tilt Base to Mounting Pipe
Install the Tilt Base to the 2" mounting pipe using two DXE-SSVC-2P Stainless Steel V-Clamps
allowing approximately 4-1/2" clearance between the bottom of the tilt base plate, to the top surface
of the DXE-RADP-3 Radial Plate as shown in Figure 3.
Make sure the Tilt Base and optional DXE-RADP-3 Radial Plate are oriented correctly for the
direction you wish to tilt the antenna. See Figure 8 which shows the tilt action.
Tighten the clamps evenly so the length of the exposed threads is approximately equal. Any clamp
should be tightened evenly from side-to-side with an equal amount of thread above each nut.
Figure - 3

- 11 -
Vertical Base Section
The base section is made up of an insulated Extren®mounting channel, a mounting plate with
hardware, two 2" x 3/8" U-Bolt assemblies and the base antenna section which is 2" OD thick wall,
36" long with a hole drilled at bottom end for the feedpoint hardware.
Using Figure 4, attach the aluminum backing plate to the back of the insulated channel. The base
hardware kit contains four 2" hex head bolts, four flat washers, four aluminum spacers, four split
washers and four nuts. From the inside of the channel, insert a 2" hex head bolt with a flat washer
through each of the middle four holes, through the backing plate. Put on the aluminum spacer, a
split washer and a plain hex nut. Tighten firmly, but not enough to crush the insulated channel.
Figure - 4
Using the 36" base section tube, install the feedline 1/4-20 x 1" long bolt through the hole in the
tube from the inside, so the threads stick out.
Put on a 1/4" star washer, 1/4" flat washer, then a 1/4-20 nut. Tighten securely.
Add another 1/4" star washer, 1/4" flat washer and 1/4-20 nut, but do not tighten. The feedline from
the UNUN attaches to this hardware. Figure 5 shows the completed feedpoint assembly.
Figure - 5

- 12 -
Install the lower section to the insulated channel using the two 2" x 3/8" U-Bolts, two saddle
clamps, four 3/8" flat washers, four 3/8" split washers, and four 3/8" hex nuts as shown in Figure 6.
The base section tube should extend 1-3/4" beyond the bottom of the U-bolt clamp.
The feedpoint hardware should be coming out on the left side as you look at the lower section as
shown in Figure 6.
When tightening, observe the split washers. When they fully seat (flatten out), the clamp is tight
enough. Any clamp should be tightened evenly from side-to-side with an equal amount of thread
above each nut.
Figure - 6

- 13 -
Base Section to Tilt Base
Place the Lower Base Section into the holes of the mounted Tilt Base and loosely install the Tilt
Base mounting hardware shown in Figure 7. Leave the flange nuts and Nyloc nuts slightly loose.
Figure - 7
Using a wrench or nut driver, securely tighten the two Nyloc nuts at the bottom of the Tilt Base.
Then loosen them one-half turn each. This will allow proper movement of the Tilt Base while
raising or lowering the antenna. It is not necessary to tighten these nuts more securely unless further
tilt operation is no longer required. They should not be loosened more than one-half turn at any
time.

- 14 -
Test the tilt function to ensure proper clearances. Standing in front of the Tilt Base, lift the antenna
base section, slide it to the right, and let it down slightly until the lower outside bolt is resting in the
pivot point. Then slowly tilt as shown in Figure 8. Make sure when you are tilting the antenna to
lift, slide to the right, and then tilt. Be careful to keep the pivot bolt resting in the pivot point.
Reverse the process when raising the antenna.
It is important to note that the lower, outside bolt becomes the pivot point while raising or lowering
the antenna. This pivot bolt MUST be retained in the pivot point. It seems natural to push the
antenna toward the Tilt Base while raising. Push up while raising, but not toward the base since this
could cause the pivot bolt to lift out of the slot and allow the mechanism to bind up and bend the
lower bolts.
The Tilt Base is not made to support the whole antenna by itself when tilted. When the antenna is
tilted over, ensure you have some sort of table, stand, or saw horse to set the antenna on to aid in
supporting the weight. When the antenna is in the upright position, ensure the mounting hardware
(reference Figure 7) is tightened.
Figure - 8 - Tilt Action
Note: A pair of sawhorses or ladders should be used to support the vertical sections during
assembly with the tilt-base and whenever the vertical is tilted down. Do not allow the
Tilt Base to support the entire weight of the vertical when horizontal.
Assembling the Vertical Sections
Note: DXE-P8A -Penetrox™A Anti-Oxidant should be used between all antenna element
sections. Penetrox™ A is an electrical joint compound to affect a substantial electrical
connection between metal parts such as telescoping aluminum tubing or other antenna
pieces. It ensures high conductivity at all voltage levels by displacing moisture and
preventing corrosion or oxidation

- 15 -
When assembling any telescoping aluminum tubing sections you should take the following steps:
1. Make sure the edges are smooth and not sharp. Deburring may be necessary, since burrs and
shavings can occur on seams as well as edges. All surfaces need to be completely smooth to
allow easy assembly of tubing sections.
Caution
Aluminum tubing edges can be very sharp.
Take precautions to ensure you do not get accidentally cut.
The raised particles and shavings that appear when the aluminum tubing is machined are
referred to as burrs, and the process by which they are removed is known as deburring.
Deburring is a finishing method used in manufacturing. Our aluminum tubing is machine cut on
both ends and machine slit on one end. Although DX Engineering manufactured aluminum
tubing is deburred, you should further assure that there are no ragged edges or protrusions.
Use the DXE-UT-KIT-DBR for this operation.
2. Clean the inside of the aluminum tubing to clear out any dirt or foreign material that would
cause the aluminum tubing sections to bind during assembly. Do not use any type of oil or
general lubricant between the aluminum tubing sections. Oils or general lubricants can cause
poor electrical connections for radio frequencies.
3. Clean the outside of the aluminum tubing to clear any dirt or foreign material that would cause
the clamps to malfunction during assembly.
4. The use of DXE-P8A Penetrox™A is highly recommended. Penetrox™ A is an electrical joint
compound which effects a substantial electrical connection between metal parts such as
telescoping aluminum tubing or other antenna pieces. Using Penetrox™ A assures high
conductivity at all voltage levels by displacing moisture and preventing corrosion or oxidation.
5. When assembling the aluminum tubing sections, ensure the area is clear of grass, dirt or other
foreign material that could cause problems during assembly of the closely fitted telescoping
sections.
Assemble the vertical sections in an area that is flat and has sufficient room for the length of the
antenna during assembly. Lay the tubing out in descending OD sizes. Orient the slits in the tubes
toward the top of the antenna. The bottom 2-1/8" section has slits at both ends. All the sections are
72" long.

- 16 -
Each tubing section is inserted 4" into the next larger tube with the exception of the bottom 2-1/8"
OD tube. Assembly is easier if the overlaps in the tubing sections are pre-marked. A dark color felt-
tip marker works well. Measure and mark 4" from the end of each tube without the slit using a
marker so it will be clearly visible. Mark the 8" long 1-3/8" OD tube at 4" (middle) as well. Mark
the 36" long tube attached to the tilt base section 4" from the top. The next tube should never be
above this mark.
Locate the hardware pack containing the eight element clamps. Refer to
Figure 11 for element clamp sizes and placement. Slide all the clamps
over each section before putting them together. You can lightly tighten
the clamps just below the slits in each section to hold them until needed.
Align the clamp screws on each section to face the same direction. At
final assembly, body of the clamp should be positioned between the slits
in the tubes and 1/8" from the edge of each tube as shown in Figure 9.
Figure - 9
Using Figure 10 and Figure 11 for dimensions, assemble the 1-1/2" sections with slits at both ends
to the 1-1/2" section with slits in one end using the smaller 1-3/8" OD 8" tube. Insert the 8" tube 4"
(as marked) into the slit ends of both top section 1-1/2" tubes and tighten the clamps.
Making sure dirt or grass
does not adhere to the
sections to be joined, insert
the marked end of the 2"
tube into the 2-1/8" bottom
tube until the 4 inch mark on
the 2" tube is even with the
top of the larger tube section.
Position one of the element
clamps at the very end, but
not hanging over the edge.
Make sure the body of the
element clamp is positioned
between the slits and tighten
securely. Repeat the
procedure with the marked
end of the 1-7/8" tube and
the 2" tube using one of the
smaller element clamps.
Continue mating the smaller
tubes inside the larger ones.
Double-check the vertical
sections you have just
assembled.
Figure 10

- 17 -
Figure 11 - MBVA-1UP Section Dimensions

- 18 -
Mating the Vertical Sections to the Tilt Base
CAUTION: Attempting final assembly without proper precaution can be dangerous.
You should have someone help you steady the vertical antenna sections during
mating with the base section.
Note: A pair of sawhorses or ladders should be used to support the vertical sections
during assembly with the Tilt Base and whenever the vertical is tilted down. Do not
allow the tilt-base to support the entire weight of the vertical when horizontal.
When the upper element sections are assembled together install the black vinyl cap in place at the
top of the smallest element section.
Mate the vertical sections to the base tube section by sliding the bottom 2-1/8" OD element of the
vertical over the 2" OD base section element (which was previously mounted to the insulated
channel) to the mark you made on the tube earlier. See Figure 11. The two sections will have a
snug fit, so use a small amount of Penetrox A on the bottom section to make the fit easier. Slide the
band clamp down to the edge of the bottom section, between the slits, and tighten. Overall antenna
length from the top to the feedpoint is 43 feet.
Raising the Vertical
DANGER: Make sure you have not inadvertently located the
antenna underneath power lines.
Residential power lines are often less than 40' high.
Contact With Any Power or Utility Lines Can Be Lethal !
The tilt-base certainly makes it easier however, this antenna can be challenging to put up the first
time or with gusty winds. If you have properly laid out your optional guy system in advance, it will
help keep the vertical stable as you raise it –and stop you from
going beyond vertical at the apex of the lift.
Make sure the optional guy ropes are in the clear before you
begin.
While raising the antenna, keep a constant pulling pressure away
from the Tilt Base. This will ensure that the pivot point bolt will
not jump out of the pivot slot and cause the tilt mechanism to
bind up and bend the bolts.
Starting from the top of the antenna, walk it up slowly using an overhead hand-over-hand motion,
maintaining a slow and steady pace.

- 19 -
The antenna mounting channel must be kept in parallel alignment with the tilt-base plate to prevent
binding until it is positioned in the tilt-base. Once the antenna is vertical, lift and slide the antenna
to the left toward the tilt-base mounting pipe to allow the two parts of the tilt-base to line up and
drop down into the slots. Lightly tighten the top flange nuts on the tilt-base to hold the antenna.
Note: As you raise the antenna to the vertical position, it’s important to
maintain the parallel alignment between the antenna mounting channel
and the Tilt Base backing plate to minimize binding. Make sure the lower
tilt-base bolts are never excessively loose before raising. They should be
first tightened securely and then backed off no more than 1/2 turn
Once the antenna is fully raised, tighten the tilt base hardware (Top: two Nyloc nuts and two flange
nuts, Bottom: two Nyloc nuts.)
Assembling the UNUN Mounting Bracket
Using the #6 hex head bolts, #6 flat washers, and #6 Nyloc nuts, attach the UNUN to the patented
UNUN Bracket with the SO-239 connector facing down. Tighten the Nyloc nuts so they are snug.
Do not over tighten since the mounting tabs on the UNUN are plastic.
Attach the custom stainless steel 90 degree studded element clamps to the UNUN Bracket using the
aluminum spacers and #10 Nyloc nuts as shown in Figure 12. Snug the #10 Nyloc nuts just to the
point that you can still rotate the custom studded element clamps. These Nyloc nuts will be
tightened later.
Figure 12