Chameleon Antenna CHA RXL User manual

LF/MF/HF
Receive Loop Antenna
(CHA RXL)
Operator’s Manual
Nevada - USA
WWW.CHAMELEONANTENNA.COM
VERSATILE –DEPENDABLE –STEALTH –BUILT TO LAST

CHA RXL Page 2
Table of Contents
Introduction ..............................................................................................................................................3
Parts of the Antenna.................................................................................................................................5
Receive Loop Assembly.............................................................................................................................8
Mast Mount. .............................................................................................................................................8
Loop Assembly. .........................................................................................................................................9
Camera Tripod Mount...............................................................................................................................9
Table Top Installation..............................................................................................................................10
Other Mounting Options.........................................................................................................................10
Connecting the Receive Loop Antenna...................................................................................................10
Troubleshooting......................................................................................................................................10
Specifications ..........................................................................................................................................11
Accessories..............................................................................................................................................12
Chameleon AntennaTM Products............................................................................................................12
References ..............................................................................................................................................12
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.
Photographs and diagrams in this manual may vary slightly from current production units due to manufacturing
changes that do not affect the form, fit, or function of the product.
IMPORTANT: This is a RECEIVE-ONLY antenna - DO NOT TRANSMIT using this antenna, as doing so will
permanently damage the electronic preamplifier!
The Receive Loop must be installed a minimum of 25 feet from other antennas in use by transmitters
transmitting 100 Watts or more.
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.

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Introduction
Thank you for purchasing and using the Chameleon AntennaTM Low Frequency (LF) / Medium Frequency (MF) / High
Frequency (HF) Receive Loop Antenna (CHA RXL). You are now part of the magnetic loop antenna craze that is
sweeping the amateur radio and shortwave listener community. Magnetic loop antennas have been used for
decades by armed forces around the world, but are just now receiving serious attention by hams and SWLs. The
CHA RXL is a new design high performance LF / MF / HF receive-only loop antenna that is weather resistant and can
be permanently mounted on an outdoor TV-style antenna mast, used portable on an apartment balcony or next to
an RV using a camera tripod, or indoors placed on a table top. The CHA RXL can receive on all frequencies from
135.7 KHz to 30.0 MHz with no tuning. Its’ broadband design and high-performance preamplifier make the CHA RXL
ideal for Software Defined Radios (SDRs), panadapters, hams wanting a small low-noise receive antenna, shortwave
listeners (SWLs), AM broadcast band listeners, or anybody needing a small receive antenna.
Receive loops are very quiet and highly directional. With the built-in preamplifier, the CHA RXL will enable clearer
reception than many large horizontal wire or vertical antennas. Field trials demonstrated that with the CHA RXL
mounted outside, signals were typically only around one to two S-units lower than a full-size dipole antenna, but
that interference was less, resulting in improved readability.
The CHA RXL consists of a rigid 36-inch Loop, a Loop
Preamplifier, a BIAS-T DC Power Injector, a 12V DC
Power Supply, and mounting bracket. Plate 1 shows
the CHA RXL mounted on a camera tripod on a deck.
The key design features of the CHA RXL are:
✓Portable - small, lightweight, and easy to setup;
✓Reduced noise;
✓Highly directional;
✓Wideband design –covers LF/MF/HF;
✓Electronic preamplifier with negative gain slope -
more gain at the low end, where it’s needed
most;
✓Balanced input electronic preamplifier to
eliminate environmental noise and ground loops;
✓Power protected from reverse polarity and short
circuits;
✓Flexible mounting options –TV mast outside,
camera tripod, or table top;
✓Stealthy –the powder-coated Navy gray loop
fades into the background sky;
✓Flexible power –use included 120V AC power
supply or operate portable using 12V DC; and
✓Receives on new 2200m and 630m ham bands -
become a WSPR Reporting Station and join the
fun!
Plate 1. CHA RXL on Camera Tripod (tripod not included).
A small receiving loop antenna receives at all
elevations from horizon to zenith, making it an
equally effective antenna for both receiving local
(including NVIS) and long-distance (DX)
communication. It is highly directional in the plane of

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the loop, as shown in Figure (1), not broadside to the
loop like a full-wave loop antenna.
Plate 2. Small Receive Loop Directivity.
A high-level block diagram of the CHA RXL is shown
in figure (1).
Figure 1. Receive Loop High-Level Block Diagram.
Antennas built by Chameleon AntennaTM are
versatile, dependable, stealthy, and built to last.
Please read this operator’s manual so that you may
maximize the utility you obtain from your CHA RXL
antenna.

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Parts of the Antenna
The CHA RXL is comprised of the following components, see plates (3) and (4):
Plate 3. CHA RXL Loop and Preamplifier.
Plate 4. CHA RXL Preamplifier.
a. Receive Loop. The Receive Loop consists of a 36-inch diameter rigid aluminum loop with a Navy gray powder
coating.
b. Preamplifier Unit. The Preamplifier Unit houses the preamplifier assembly and is used as the mount for the
Receive Loop and Camera Tripod Attachment.
c. Remote Antenna Connection. The Remote Antenna Connection is a BNC socket used to connect the Coaxial
Cable from the Preamplifier Unit to the BIAS-T Unit.
d. Loop Flange. The Loop Flanges are used to mechanically and electrically connect the Receive Loop and are
located on the sides of the Preamplifier Unit and ends of the Receive Loop. In the Export Version of the CHA
RXL, there is also a set of Loop Flanges at the top-center of the Receive Loop and the loop is made of two pieces.

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e. Camera Mount Socket. The Camera Mount Socket is a standard 1/4” x 20 threaded camera socket, located on
the bottom of the Loop Preamplifier Unit, used to attach the CHA RXL to a heavy-duty Camera Tripod. An
optional mount can convert the 1/4” x 20 camera socket to a 3/8” x 24 antenna stud for use with optional
Chameleon AntennaTM antenna mounts (see accessories list).
f. Mounting Bracket Connections. The two Mounting Bracket Connections are used to attach the Mounting
Bracket to the Preamplifier Unit.
g. Mounting Bracket. Mounting Bracket, shown in plate (5) is used to mount the CHA RXL to a TV-style 1 ¼ inch
antenna mast. The Mounting Bracket is not used if the CHA RXL is mounted on a camera tripod or placed on a
table top.
Plate 5. CHA RXL Mounting Bracket and Hardware.
h. Preamplifier Mounting Holes. The two Preamplifier Mounting Holes are used when attaching the Mounting
Bracket to the Preamplifier Unit with two Allen Head screws.
i. U-Bolt Holes. The four U-Bolt Holes are used to attach the Mounting Bracket to a TV-style mast with a pair of
¼” D X 3” L X 1 ¾” W U-Bolts.
j. BIAS-T Unit. The BIAS-T Unit is used to inject 12V DC power into the Coaxial Cable to provide power to the
electronic preamplifier. The BIAS-T Unit is not weather resistant and must be installed indoors or otherwise
protected from the elements.
k. Radio Connection. The Radio Connection is a UHF Socket (SO-239) used to connect a coaxial cable jumper from
the BIAS-T Unit and the radio receiver.
l. Intentionally Not used.

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m. Local Antenna Connection. The Local Antenna Connection is a BNC socket used to connect the Coaxial Cable to
the BIAS-T Unit from the Preamplifier Unit.
Plate 6. 12V DC Power Supply (left) and BIAS-T Unit (right).
n. Power Indicator Light. The Power Indicator Light is a green LED that is illuminated when 12-14V DC power is
applied to the BIAS-T Unit.
o. DC Power Socket. The DC Power Connection is a 2.1mm X 5.5mm coaxial socket on the BIAS-T Unit used to
accept 12-14V DC power. The center pin is positive.
p. DC Power Supply. The DC Power Supply is a miniature wall-mounted power supply used to supply 12V DC
power to the BIAS-T Unit. Input to the Power Supply is 120V AC 60 Hz.
q. DC Power Plug. The DC Power Plug is a 2.1mm X 5.5mm coaxial plug used to provide power from the DC Power
Supply.

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Receive Loop Assembly
The CHA RXL antenna and can be permanently mounted on an outdoor TV-style antenna mast, used portable on an
apartment balcony, or next to an RV, using a camera tripod, or indoors placed on a table top. Prepare the CHA RXL
for the intended installation method and then assemble the loop using the procedures below.
Mast Mount. Perform the following steps to prepare the CHA RXL for mast mounting, see plates (7)-(9). If not
mounting the CHA RXL on a mast, skip to the Loop Assembly procedure.
1. Layout the mast mounting hardware as shown in
the right photograph in plate (5).
2. Insert both U-Bolts through the U-Bolt Holes (i) in
the outside of the Mounting Bracket (g), as
shown in plate (7).
3. Place a ¼” Flat Washer over each of the four
threaded bolts of the inserted U-Bolts.
4. Place a ¼” Split Washer over each of the four
threaded bolts of the inserted U-Bolts.
5. Thread a ¼” Nut over each of the four threaded
bolts of the inserted U-Bolts.
Plate 7. Mast Mounting Bracket Assembly.
6. Position the Preamplifier Unit (b) upside down on
the work surface.
7. Place the Mounting Bracket on the bottom of the
Preamplifier Unit, as shown in plate (8). The
Mounting Bracket can be installed in either
direction, depending on your installation
requirements.
Plate 8. Attaching Mounting Bracket.
8. Insert a ¼” Allen Head Bolt through both
Preamplifier Mounting Holes (h) and into the
corresponding threaded holes in the Preamplifier
Unit mounting plate on the bottom of the
Preamplifier Unit.
9. Tighten both Allen Head Bolts using a 5/32” Allen
wrench until tight, as shown in plate (9).
Plate 9. Tightening Allen Head Bolts.

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Loop Assembly. Perform the following steps to assemble the Loop, see plate (10).
1. Position the Loop (a) upside down (open end
up).
2. Hold the Preamplifier Unit (b) upside down
and mate the Loop Flanges (d) flat side to flat
side on one end of the Loop and Preamplifier
Unit.
3. For permanent outside installation, we
recommend treatment of the Loop Flanges
and hardware with Permatex® Anti-Seize
Lubricant.
4. Place a #10 Flat Washer over one #10
Knurled Knob Bolt.
5. Insert the #10 Knurled Knob Bolt through the
Loop and Preamplifier Unit Loop Flanges.
6. Place a #10 Flat Washer over the inserted
Knurled Knob Bolt.
7. Place a #10 Split Washer over the inserted
Knurled Knob Bolt.
8. Thread a #10 Wing Nut onto the inserted
Knurled Knob Bolt and tighten until firmly
tightened by hand.
9. The assembled end should look like that
pictured in plate (10).
Plate 10. Loop Assembly.
10. Repeat steps (2) through (9) for the other side of
the Loop and Preamplifier Unit.
Plate 11. Assembled Loop and Preamplifier Unit.
11. The assembly should look like that pictured in
plate (11).
Camera Tripod Mount. Perform the following steps to mount the CHA RXL on a camera tripod. The
camera tripod must be capable of holding 6 lbs.
1. Position the Preamplifier Unit (b) Camera Mount
socket (e) over the standard ¼” x 20 threaded
stud of the tripod.
2. Tighten tripod threaded stud until snug.
3. The completed assembly should look like that
pictured in plate (12).
Plate 12. Preamplifier on Camera Tripod.

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Table Top Installation. Peel off the adhesive backing on each of the Rubber Feet and stick one in
each corner of the Mounting Plate on the bottom of the Preamplifier Unit (b). The CHA RXL can be
placed on a table top or other flat surface inside your building. Performance of the CHA RXL may be
degraded by the building construction material or proximity to interior sources of Radio Frequency
Interference (RFI).
Other Mounting Options. Chameleon AntennaTM sells an optional adapter (CHA SS ADAPTER) that converts
the ¼” X 20 camera tripod mount to a 3/8” X 24 antenna mount. Using this adapter, you can mount the CHA RXL
on any of the optional Chameleon AntennaTM antenna mounts, such as the Universal Clamp Mount (CHA UCM).
Connecting the Receive Loop Antenna.
Perform the following procedure to connect the CHA RXL to your LF/MF/HF Radio Receiver.
1. Connect one end of the Coaxial Cable (not
supplied) to the Remote Antenna Connection (c)
on the Preamplifier Unit (b).
2. Connect the other end of the Coaxial Cable to the
Local Antenna Connection (m) on the BIAS-T Unit
(j).
Because the BIAS-T supplies 12V DC power to the
Loop Preamplifier through the Coaxial Cable, do not
install any other electrical device, such as an
antenna switch, duplexer, rotor controller, etc.
between the BIAS-T Unit and the Loop Preamplifier.
3. Connect one end of a Coaxial Jumper Cable (not
supplied) to the Radio Connection (m) on the
BIAS-T Unit.
4. Connect the other end of the Coaxial Jumper
Cable to the Radio Receiver.
5. Connect the DC Power Plug (q) to the DC Power
Socket (o) on the BIAS-T Unit (j).
6. Plug the DC Power Supply (p) into 120V AC
electrical outlet. The Power Indicator Light (n)
will illuminate green.
7. Perform an operational test.
IMPORTANT: This is a RECEIVE-ONLY antenna -
DO NOT TRANSMIT using this antenna, as doing
so will permanently damage the electronic
preamplifier!
The Receive Loop must be installed a minimum
of 25 feet from other antennas in use by
transmitters transmitting 100 Watts or more.
Troubleshooting
1. Ensure the Power Indicator Light is illuminated green. Replace Power Supply if Power Indicator Light is not
illuminated. If the problem is not resolved by replacing the Power Supply, replace the BIAS-T Unit.
2. Ensure Loop Flange connections are securely tightened.
3. Ensure all Coaxial Cable Connections are securely tightened.
4. Inspect Coaxial Cable and Coaxial Jumper Cable for cuts in insulation, exposed shielding, or loose connectors.
Replace if damaged. Most problems with antenna systems are caused by the coaxial cables and connectors.
5. If still not operational, contact us for technical support at [e-mail].

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Specifications
•This is a RECEIVE-ONLY antenna –DO NOT TRANSMIT using this antenna.
•The Receive Loop must be installed a minimum of 25 feet from other antennas in use by
transmitters transmitting 100 Watts or more.
•Frequency: 135.7 KHz –30.0 MHz (continuous coverage, which includes the 2200m, 630m, and 160-10m
amateur radio service bands and all medium and shortwave broadcast bands)
•Diameter: 36 inches
•Gain: Frequency dependent, see figure (2)
•RF Connections:
oRadio Receiver: UHF Socket (SO-239) for Coaxial Jumper to Radio Receiver.
oBIAS-T and Preamplifier Unit: BNC Socket. Coaxial Cable between BIAS-T Unit and Preamplifier
Unit must have BNC Male connectors at each end (see accessories list).
•Power: 12V DC (normally supplied by the included DC Power Supply, which requires 120V AC 60 Hz)
•Weight: 6 lbs.
•Mount: 1 ¼” mast, camera tripod, or table top
•Personnel Requirements and Setup Time: one operator, around 5 minutes
Figure 2. Preamplifier Gain.

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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.
•Stainless Steel Adapter (CHA SS ADAPTER) - converts the ¼” X 20 camera tripod mount to a 3/8” X 24
antenna mount.
•Universal Clamp Mount (CHA UCM) –heavy-duty antenna mount, suitable for portable or semi-
permanent use.
•Coaxial Cables in 12’, 25’, and 50’lengths with BNC Male connectors at each end.
Chameleon AntennaTM Products
Please go to http://chameleonantenna.com for information about additional quality antenna products available
for purchase from Chameleon AntennaTM –The Portable Antenna Pioneer.
References
1. Silver, H. Ward (editor), 2013, 2014 ARRL Handbook for Radio Communications, 91st Edition, American Radio
Relay League, Newington, CT.