CHAMELEON ANTENNA DBVHF-UHF Instructions manual

Portable Dual-Band

Vertical/Horizontal Antenna

User Guide

Nevada - USA

WWW.CHAMELEONANTENNA.COM

VERSATILE – DEPENDABLE – STEALTH – BUILT TO LAST

Dual-Band Antenna Page 2

Table of Contents

Introduction .............................................................................................................................................. 3

VHF/UHF Propagation ............................................................................................................................... 3

Portable Dual-Band Vertical/Horizontal Antenna Description ................................................................. 4

Parts of the Portable Dual-Band Vertical/Horizontal Antenna ................................................................. 4

Assembling the Portable Dual-Band Vertical/Horizontal Antenna ........................................................... 5

Troubleshooting ........................................................................................................................................ 7

Specifications ............................................................................................................................................ 7

Warranty ................................................................................................................................................... 8

Accessories ................................................................................................................................................ 9

Chameleon AntennaTM Products .............................................................................................................. 9

References .............................................................................................................................................. 10

WARNING! Never mount this, or any other antenna near power lines or utility wires! Any materials:
ladders, ropes, or feedlines that contact power lines can conduct voltages that kill. Never trust insulation to protect
you. Stay away from all power lines.

WARNING! Never operate this antenna where people could be subjected to high levels of RF exposure,
especially above 10 watts or above 14 MHz. Never use this antenna near RF sensitive medical devices, such as
pacemakers.

All information on this product and the product itself is the property of and is proprietary to Chameleon AntennaTM.
Specifications are subject to change without prior notice.

!

!

Dual-Band Antenna Page 3

Introduction

Thank you for purchasing and using the Chameleon Antenna

TM

Portable Dual-Band Vertical/Horizontal Antenna. This
antenna, shown in plate (1), will enable operation on both the 144 MHz (2m) and 440 MHz (70cm) Amateur Radio
Service bands in both vertical and horizontal polarization configurations. This innovative antenna concept is
designed to be the most versatile and rugged portable Very High Frequency (VHF) / Ultra High Frequency (UHF)
antenna available and will enable the operator to communicate on CW and SSB using horizontal polarization and on
FM simplex and repeaters using vertical polarization with one simple antenna whip change.

Plate 1. Portable Dual-Band VHF/UHF Antenna.

The Chameleon Antenna

TM

Portable Dual-Band
Vertical/Horizontal Antenna is an ideal accessory for
the Modular Portable Antenna System (MPAS) as part
of a total portable communication system. It will
greatly extend communications range when using a
portable VHF/UHF hand-held transceiver (HT) as

compared to the typical flexible whip “rubber duck”

antenna. The Portable Dual-Band Vertical/Horizontal
Antenna also provides horizontally polarized

capability, that is usually forgotten by most
manufacturers of portable VHF/UHF antennas, for
use with transceivers that have CW/SSB modes. It is
especially suitable for use when camping or in a
Recreational Vehicle (RV), apartment, condominium,
HOA, or inside an attic - anywhere you need
portability or have limited space or restrictions
against permanent antennas. It would also be useful
as a backup base station antenna or for EMCOMM.
The Chameleon Antenna

TM

Portable Dual-Band
Vertical/Horizontal Antenna is made from a durable
weather-resistant case and easily attaches to an

antenna mast that has a 3/8” x 24 stud socket, such

as the CHA MIL EXT 2.0 collapsible mast or the CHA
JAW MOUNT (both sold separately).
Antennas and antenna accessories built by
Chameleon Antenna

TM

are versatile, dependable,
stealthy, and built to last. Please read this user guide
so that you may maximize the utility you obtain from
your Chameleon Antenna

TM

Portable Dual-Band

Vertical/Horizontal Antenna.

VHF/UHF Propagation

VHF and UHF radio provides relatively inexpensive and reliable local voice and data communication capability. It is
especially suitable for local areas where normal telecommunications are not available, too costly or scarce, or where
the commercial telecommunications infrastructure has been damaged by a natural disaster or military conflict.

Although VHF/UHF radio is a reasonably reliable method of communication, VHF/UHF radio waves propagate
through a complex and constantly changing environment and are affected greatly by terrain and to a lesser extent,
weather. A detailed explanation of the theory of VHF/UHF radio wave propagation is beyond the scope of this
operator’s manual, but an understanding of the basic principles will help the operator decide what frequency,
communications mode, and polarization will support their communication requirements.

VHF/UHF radio waves propagate from the transmitting antenna to the receiving antenna using two general methods:
line-of-sight and refraction.

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The broad term “line-of-sight” includes actual line-of-sight (when the transmitting station and receiving station have
an unobstructed, direct path between each other) as well as reflections. True line-of-sight range for most portable
VHF/UHF stations is only a few miles, so longer range typically occurs through reflections, caused by intervening
terrain and structures. Signal enhancements and fading are caused by reflections arriving from different directions
and phases (referred to as “multipath”). You have probably noticed this effect, called “picket fencing” by hams,
while operating mobile. A radio signal also travels further than the visual horizon due to a tendency for radio waves
to be refracted slightly groundward when travelling through the atmosphere. This distance is called the radio
horizon and can be estimated by the formula:

𝑑 =√2 × ℎ

Where: d = distance (miles) and h = antenna height (feet). For example, the maximum line-of-sight range for a
portable station using this antenna and communicating with a typical VHF/UHF FM base station would be around 12
miles. Typical communication range using a repeater is around 30 miles and, of course, being on a mountain or hill
top can greatly increase this.

Ducting and troposcatter are both forms of refraction enabling communication beyond the radio horizon. Apart
from the normal refraction described above, severe refraction due to tropospheric temperature inversions cause a
rare phenomenon known as ducting. VHF/UHF signals propagated by ducting can travel for several hundred miles
with little loss. The temperature inversions that causes ducting are associated with climatic conditions like frontal
boundaries.

A more common and reliable propagation technique for over-the-horizon VHF/UHF communication is troposcatter.
Troposcatter is caused by scattering of radio waves by wavelength-sized gradients in the common scattering volume
between two stations. Normally, these transmissions would pass through the layers of the atmosphere and into
space, but due to the gradients, a small part of the transmission is scattered towards the receiving station, and thus
made able to be received. Troposcatter propagation is almost always present, but due to the large path losses,
works best with narrow band modes (e.g. CW and SSB), high power, high gain directional antennas, and most
important, high elevations with no obstructions low to the horizon (like on mountain or hill tops). The calculated
maximum range for troposcatter propagation between a station using this antenna in the horizontal configuration,
SSB mode, and with a power level of 100 Watts, communicating with a typical VHF/UHF base station, is around 160
miles for VHF and 70 miles for UHF.

Portable Dual-Band Vertical/Horizontal Antenna Description

The Chameleon AntennaTM Portable Dual-Band Vertical/Horizontal Antenna is comprised of a weather resistant
base designed to allow mounting of the two included dual-band VHF/UHF whip antennas that can be easily
configured as either a quarter-wave vertical monopole or half-wave horizontal dipole antenna. The Antenna Base
(a) can be installed on any mount that accepts the standard 3/8” x 24 stud, such as the CHA MIL EXT 2.0 collapsible
antenna extension or the CHA JAW MOUNT (both available from Chameleon AntennaTM).

Parts of the Portable Dual-Band Vertical/Horizontal Antenna

The Portable Dual-Band Vertical/Horizontal Antenna is comprised of the following components, see plate (2).

a. Antenna Base. The Antenna Base is the center of the Portable Dual-Band Vertical/Horizontal Antenna

System and has three 3/8” x 24 couplings, used to mount the dual-band whip antennas in either a
horizontal or vertical position.

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b. Dual-Band Whip. The Dual-Band Whip is a quarter wave antenna for the 144 MHz (2m) and 440 MHz

(70cm) Amateur Radio Service bands.

c. Antenna Stud. The Antenna Stud is a standard 3/8” x 24 stub base used to affix the Dual-Band Whip (b)

to the Antenna Base.

Plate 2. Portable Dual-Band Vertical/Horizontal Antenna Components.

Coupling 1 - 3. The three 3/8” x 24 threaded Couplings are used to attach the Dual-Band Whips (c) to the

Antenna Base. Each Coupling is marked with a color during final assembly, usually they are: Blue (1) for
the Vertical Dual-Band Whip, Red (2) for the Horizontal Dual-Band Whip, and Green (3) for the Dual-Band
Whip used as the radial/counterpoise. The labelling in Plate (2) the colored labels on the actual Antenna
Base may not be identical on all units. The purpose of the labelling is to demonstrate the installation of
the Dual-Band Whips in the Vertical and Horizontal configurations.

d. Base Stud. The Base Stud is used to mount the Antenna Base (a) to the mast or mount used to erect the

antenna.

e. UHF Socket. The UHF Socket (SO-239) is used to connect the coaxial cable assembly (not supplied, but

available as an option).

Assembling the Portable Dual-Band Vertical/Horizontal Antenna

Assembly of the Portable Dual-Band Vertical/Horizontal Antenna is very quick and easy – just perform the
following steps.

1. For vertical polarization (used for FM, repeaters, APRS/Packet, and VARA FM), connect one Dual-Band

Whip (b) Antenna Stud (c) to Coupling (1) on top of the Antenna Base(a), as shown in figure (1).

2. For horizontal polarization (used for CW, SSB, and SSB-based data modes, like WSPR, FT-8, or PSK-31),

connect one Dual-Band Whip Antenna Stud to Coupling (2), on the left side of the Antenna Base (when
the UHF Socket is facing you), as shown in figure (1).

3. Connect the Radial/Counterpoise Dual-Band Whip Antenna Stud to Coupling (3), on the right side of the

Antenna Base (when the UHF Socket is facing you), as shown in figure (1).

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Figure 1. Portable Dual-Band Vertical (left) / Horizontal (right) Antenna.

4. Attach the Antenna Base to the mount on the support mast (not supplied, but available as an accessory) by

threading the Base Stud (d) into the mount’s 3/8” x 24 socket.

5. Attach the coaxial cable (not supplied, but available as an accessory) to the UHF Socket (e).

6. Raise the antenna mast.

7. Install non-conducting guy lines (not supplied, but available as an accessory), if needed.
The assembled and erected antenna should look similar to that pictured in plate (3).

8. Perform operational check.

9. To change antenna polarization, perform step 1 or 2, as appropriate.

Plate 3. Assembled and Erected Portable Dual-Band Vertical/Horizontal Antenna.

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Troubleshooting

Most problems experienced when using the Portable Dual-Band Vertical/Horizontal Antenna are likely to be
caused by defects in the coaxial cable assembly. The Dual-Band Whips (b) have been pre-tuned by the
manufacturer and should not require field tuning. Perform the following steps to troubleshoot problems with the
Portable Dual-Band Vertical/Horizontal Antenna.

1. Connect a Standing Wave Ratio (SWR) Power Meter and check SWR.

2. If the SWR is greater than 1.5:1 and less than 5:1, it is likely this is a Dual-Band Whip (b) tuning problem.

Contact Chameleon Antenna for assistance.

3. Ensure the coaxial cable assembly UHF Connector Plug (PL-259) is securely tightened to the UHF Socket (e).

Recheck SWR.

4. If the SWR is still higher than 5:1, inspect and check or replace the coaxial cable. Most problems causing

extremely high SWR are caused by the coaxial cables and connectors. Recheck SWR.

5. If the SWR is still higher than 5:1, disconnect the coaxial cable from the Antenna Base (a). Use a Multi-Meter

to check for a short in the Antenna Base by placing one lead on the outside of the UHF Socket and the other
lead in the center of the UHF Socket. It should have an infinite resistance. If it has any value other than an
infinite resistance reading (within the accuracy of the meter), replace the Antenna Base.

6. Use a Multi-Meter to check for continuity in the Antenna Base by placing one lead in the center of the UHF

Socket and the other on Coupling (1). Perform the same measurement for Coupling (2). Move the Multi­Meter lead from the center of the UHF Socket to the outside of the UHF Socket and measure Coupling (3).
They all should have had zero resistance. If any of the Couplings had unexpected values (not close to zero or
infinity - within the accuracy of the meter), replace the Antenna Spoke Base.

7. If still not operating correctly, contact Chameleon Antenna for technical support. Explain to them the steps

you have already taken to isolate the problem.

Specifications

• Frequency Range: 144.0-148.0 MHz (2m) and 420-450 MHz (70cm).

• SWR: Less than 1.5:1.

• Power Handling: 100 W.

• Polarization: Vertical and Horizontal by changing the radiator whip position.

• Space Required: Maximum diameter of 40 inches.

• RF Connection: UHF Socket (SO-239)

• Personnel Requirements and Setup Time: one operator, less than 5 minutes.

• Figure (1) shows the far field plot for the vertical monopole and figure (2) shows the far field plot for the

horizontal dipole.

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Figure 1. Far Field Plot Vertical Monopole.

Figure 2 Far Field Plot Horizontal Dipole.

Warranty

The Chameleon Portable Dual-Band Vertical/Horizontal Antenna is warranted to be free from defects in materials
and workmanship for a period of 12 months from the date of purchase. To obtain warranty service, return all
components of the system to Chameleon Antenna at your expense. Chameleon Antenna will repair or replace
defective components and return the system to you at no charge. We encourage you to call us for technical
support before returning the antenna system. This warranty excludes components that have been damaged or
modified by the customer.

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Accessories

The following accessories are available for purchase from Chameleon AntennaTM. Please contact us at

[e-mail] for current prices and availability or see our website
www.chameleonantenna.com.

• Guying System. The Universal Guying System (CHA UGS) is recommended to stabilize the erected

antenna mast.

• Coaxial Cable Assembly. The CHA 50’ COAX CABLE with integrated RFI Choke is perfect for use as the

feedline to the Portable Dual-Band Vertical/Horizontal Antenna.

• Portable Collapsible Mast. The CHA MIL EXT 2.0 is an aluminum 8’ 9” antenna mast that collapses to less

than 29” for portability. The Chameleon AntennaTM Portable Dual-Band Vertical/Horizontal Antenna was

specifically designed to use this mast.

• JAW MOUNT. The CHA JAW MOUNT is a versatile antenna mount that can clamp to an existing support,

like a pole or fence rail, up to 3” thick, depending on the shape.

Recommended non-supplied accessories:

• 1/2” Combination Wrench.

• SWR Power Meter or Antenna Analyzer.

• Multi-Meter.

Chameleon AntennaTM Products

The following are a few of the quality products available for purchase from Chameleon AntennaTM. Many other
antenna products are also available. Go to www.chameleonantenna.com for ordering and more information.

CHA MPAS 2.0 – The Modular Portable Antenna
System (MPAS 2.0) is a concept allowing the radio
operator to configure and deploy the antenna system
in a variety of configurations. It covers 1.8 to 54.0
MHz and comes in a military-style backpack. Note:

includes the CHA MIL EXT 2.0 collapsible mast.

CHA F-LOOP 2.0 and CHA P-Loop 2.0 – The CHA F-
LOOP 2.0 Magnetic Loop Antenna is only 36” in
diameter and covers 3.5 to 29.7 MHz. The CHA P­Loop 2.0 is less than 34” and covers 7.0 to 29.7 MHz.
Both loops were designed with portability, ease of use
simplicity, ruggedness and high performance in mind.
They are perfect for apartment balconies.

CHA EMCOMM III – The EMCOMM III Portable
antenna is a portable High Frequency (HF) antenna
specially designed for short to long range portable
and man-pack HF communications. The EMCOMM III
Portable antenna is ideal for hiking, backpacking, and
both tent and Recreational Vehicle (RV) camping. It

would also be ideal as a backup emergency HF
antenna.

CHA TD Tactical Dipole LITE - The CHA TD LITE
(Tactical Dipole LITE) is a HF broadband antenna
specially designed for portable HF communication
where rapid deployment and simplicity of operation
is essential but compactness is essential. The antenna
will operate at all frequencies in the 1.8-54 MHz band
without any adjustment with most modern external
antenna tuners. No masts or guying are required.

CHA TD Tactical Dipole - The CHA TD (Tactical Dipole)
Antenna has been designed as an add-on for the CHA
HYBRID - MINI / MICRO. The CHA TD is a HF
broadband antenna specially designed for portable
HF communication where rapid deployment and
simplicity of operation is essential. The antenna will
operate at all frequencies in the 1.8-30 MHz band
without any adjustment with most modern internal
antenna tuners. It is ideal for use in conjunction with
modern, digitally configured, HF communication

Dual-Band Antenna Page 10

transceivers where features such as ALE and frequency hopping require true broadband capability.

References

1. Silver, H. Ward (editor), 2013, 2014 ARRL Handbook for Radio Communications, 91st Edition, American Radio

Relay League, Newington, CT.

2. Atkins, Bob, Tropospheric Loss and Link Loss Calculator, www.bobatkins.com/radio/scatter2.html.

3. Preben-Hansen, Palle, Everyday VHF, UHF, and SHF Propagation, Aagerup Mill, Denmark.