Chameleon Antenna CHA SKYLOOP 2.0 User manual

Base HF Loop Antenna
(CHA SKYLOOP 2.0)
Operator’s Manual
Nevada - USA
WWW.CHAMELEONANTENNA.COM
VERSATILE –DEPENDABLE –STEALTH –BUILT TO LAST

CHA SKYLOOP (updated February, 2020)
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Table of Contents
Introduction ..............................................................................................................................................3
HF Propagation .........................................................................................................................................3
Parts of the Antenna.................................................................................................................................4
SKYLOOP Installation.................................................................................................................................5
Troubleshooting........................................................................................................................................7
Specifications ............................................................................................................................................8
Accessories................................................................................................................................................8
Chameleon AntennaTM Products..............................................................................................................8
References ................................................................................................................................................9
Be aware of overhead power lines when you are deploying the CHA SKYLOOP antenna system. You could
be electrocuted if the antenna gets near or contacts overhead power lines.
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.

CHA SKYLOOP (updated February, 2020)
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Introduction
Thank you for purchasing and using the Chameleon AntennaTM High Frequency (HF) Base Loop Antenna (CHA
SKYLOOP). The CHA SKYLOOP is an extreme performance horizontal full-wave loop antenna. The main advantages
of a horizontal loop antenna are reduced background noise and a better gain over a dipole—which means signals
will be stronger. In fact, most operators can’t believe the increase in performance over their old dipole antenna.
The antenna is comprised of 265 feet of wire, insulators, and a matching transformer unit. The integral broadband
impedance matching network transformer allows broadband antenna tuning. The antenna will operate from 3.5 -
54 MHz (including 80m –6m amateur bands) without any adjustment with a wide range antenna tuner. The CHA
SKYLOOP is suitable for military, government agencies, non-governmental organizations (NGOs), Military Affiliate
Radio System (MARS), Civil Air Patrol (CAP), Amateur Radio Emergency Service (ARES) / Radio Amateur Civil
Emergency Service (RACES), Salvation Army Team Emergency Radio Network (SATERN), and hams looking for a
high performance wire antenna for HF base stations. Its’ low observable characteristics also make it a good choice
for hams living in developments with Homeowners Associations (HOAs), deed restrictions, or Covenants,
Conditions & Restrictions (CCRs). It is also an outstanding shortwave listening (SWL) antenna. When mounted
low, the CHA SKYLOOP will provide good Near-Vertical Incident Sky wave (NVIS) communication. The CHA
SKYLOOP antenna requires a wide range antenna tuner or coupler. Antennas built by Chameleon Antenna
TM
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 SKYLOOP antenna.
HF Propagation
HF radio provides relatively inexpensive and reliable local, regional, national, and international voice and data
communication capability. It is especially suitable for undeveloped 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 HF radio is a reasonably reliable method of communication, HF radio waves propagate through a complex
and constantly changing environment and are affected by weather, terrain, latitude, time of day, season, and the
11-year solar cycle. A detailed explanation of the theory of HF 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 and
which of the CHA SKYLOOP configurations will support their communication requirements.
HF radio waves propagate from the transmitting antenna to the receiving antenna using two methods: ground waves and
sky waves.
Ground waves are composed of direct waves and surface waves. Direct waves travel directly from the transmitting
antenna to the receiving antenna when they are within the radio line-of-sight. Typically, this distance is 8 to 14 miles
for field stations. Surface waves follow the curvature of the Earth beyond the radio horizon.
They are usable, during the day and under optimal conditions, up to around 90 miles, see table (1). Low power,
horizontal antenna polarization, rugged or urban terrain, dense foliage, or dry soil conditions can reduce the range
very significantly. The U.S. Army found that in the dense jungles of Vietnam, the range for ground waves was
sometimes less than one mile.

CHA SKYLOOP (updated February, 2020)
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Frequency
Distance
Frequency
Distance
2 MHz
88 miles
14 MHz
33 miles
4 MHz
62 miles
18MHz
29 miles
7 MHz
47 miles
24 MHz
25 miles
10 MHz
39 miles
30 MHz
23 miles
Table 1. Maximum Surface Wave Range by Frequency.
Sky waves are the primary method of HF radio wave propagation. HF radio waves on a frequency below the critical
frequency (found by an ionosonde) are reflected off one of the layers of the ionosphere and back to Earth between
300 and 2,500 miles, depending upon the frequency and ionospheric conditions. HF radio waves can then be
reflected from the Earth to the ionosphere again during multihop propagation for longer range communication. The
most important thing for the operator to understand about HF radio wave propagation is the concept of Maximum
Usable Frequency (MUF), Lowest Usable Frequency (LUF), and Optimal Working Frequency (OWF). The MUF is the
frequency for which successful communications between two points is predicted on 50% of the days of in a month.
The LUF is the frequency below which successful communications are lost due to ionospheric loses. The OWF, which
is somewhere between the LUF and around 80% of the MUF, is the range of frequencies which can be used for
reliable communication. If the LUF is above the MUF, HF sky wave propagation is unlikely to occur.
The HF part of the Radio Frequency (RF) spectrum is usually filled with communications activity and an experienced
operator can often determine where the MUF is, and with less certainty, the LUF by listening to where activity ends.
The operator can then pick a frequency in the OWF and attempt to establish contact. Another method is using HF
propagation prediction software, such as the Voice of America Coverage Analysis Program (VOACAP), which is
available at no cost to download or use online at www.voacap.com. The operator enters the location of the two
stations and the program show a wheel with the predicted percentage of success based on frequency and time. ALE,
which is the standard for interoperable HF communications, is an automated method of finding a frequency in the
OWF and establishing and maintaining a communications link.
Even under optimal conditions, there is a gap between where ground waves end (around 40 to 90 miles) and the
sky wave returns to Earth on the first hop (around 300 miles). NVIS propagation can be used to fill this gap. The
frequency selected must be below the critical frequency, so NVIS is can normally only be used on frequencies from
around 2 to 10 MHz. Frequencies of 2 –4 MHz are typical at night and 4 –8 MHz during the day.
Parts of the Antenna
The CHA SKYLOOP is comprised of the following components, see plate (1):
a. Matching Transformer. The Matching Transformer provides a starting mounting point and impedance
matching for the CHA SKYLOOP antenna.
b. Antenna Wire. The Antenna Wire is a 265-foot length of black insulated wire.
c. Line Winder. The Line Winder is used to store the Antenna Wire (b) when it is not in use.
d. Carabiner. The Carabiner is a removable pear-shaped stainless-steel hook with a spring-loaded gate used to
attach the Isolation Loops (e) to the Transformer Eyebolt (i).

CHA SKYLOOP (updated February, 2020)
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e. Isolation Loop. Five Isolation Loops are permanently attached to the Antenna Wire and are used to suspend
three corners of the loop and as insulators at the feedpoint.
Plate 1. CHA SKYLOOP Antenna.
f. Wire Connector. The Wire Connectors are located at each end of the Antenna Wire.
g. Ground Connection. The Ground Connection is located on the bottom of the Matching Transformer (a) and
provides an optional electrical ground for lightning protection.
h. UHF Socket. The UHF Socket, SO-239, is located on the bottom of the Matching Transformer.
i. Transformer Eyebolt. The Transformer Eyebolt is located on the top of the Matching Transformer.
j. Antenna Connection. The two Antenna Connections are located on the top of the Matching Transformer and
are used to attach the Wire Connectors (f).
k. Support Line. The Support Line (not included) is Polyester or Nylon abrasion-resistant rope used to suspend
the antenna from the necessary supports.
SKYLOOP Installation
The CHA SKYLOOP, see figure (1), is installed horizontally and requires four supports at least 64 feet apart that, when
the antenna wire is suspending from them, will form the CHA SKYLOOP approximately in the shape of a square. The
supports should also be 30 to 40 feet high, although heights as low as 10 feet will work, but with reduced
performance. An optional electrical ground wire may be used for lightning protection. The coaxial cable should beat
least 25 in length.

CHA SKYLOOP (updated February, 2020)
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Figure 1. SKYLOOP Antenna Installation.
Site Selection and Preparation.
1. Select a site to deploy the CHA SKYLOOP
horizontal loop antenna. The site must have four
supports that will position the corners of the
antenna at least 67 feet apart and 30 to 40 feet
high. Further apart is better as it will allow for
shaping and leveling the antenna loop. The loop
does not have to be perfectly square.
2. If not already attached, connect a Carabiner (d)
to each of the Isolation Loops (e) at the ends of
the Antenna Wire (b).
3. Unwind the Antenna Wire (b) from the Line
Winder (c). Lay out the Antenna Wire on the
ground approximately under where the antenna
will be erected.
4. Move the Isolation Loops (e) along the Antenna
Wire until they are near the support where they
will be suspended.
5. Using a Bowline, or similar knot, tie a long length
(minimum of 50 feet) of Support Line (k) to each
of the three Isolation Loops.
6. Place the Matching Transformer (a) on the
ground near the support where it will be
suspended.
Connect the Matching Transformer. Refer to Figure
(2) for steps (7) –(11).
Figure 2. SKYLOOP Electrical and Mechanical
Connections.
7. Attach the Carabiner from one of the Antenna
Wires to the Transformer Eyebolt (i).
8. Attach the Wire Terminal (f) on the end of the
Antenna Wire to one of the Antenna Terminals (j)
on the Matching Transformer.

CHA SKYLOOP (updated February, 2020)
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9. Attach the Carabiner from the other end of the
Antenna Wire to the Carabiner from step (7).
10. Attach the Wire Terminal on the end of the
Antenna Wire to the other Antenna Terminal.
11. Using a Bowline, or similar knot, attach a long
length (50 feet) of Support Line to the Carabiner
from step (7). Your assembly should look like
Figure (2).
12. If used, connect the ground wire to Ground
Connection (g) on the Matching Transformer.
13. Connect a CHA RFI CHOKE and coaxial cable or
Integrated RF Choke end of the CHA Coaxial
Cable assembly to the UHF Socket (h) on the
Matching Transformer.
Raise the Antenna.
14. For each corner of the antenna, using a throw
weight or other method, loop the Support Line
attached to the Insulator or Matching
Transformer over the closest support.
15. Alternately raise each corner of the antenna to
the desired height, ensuring the antenna retains
a mostly square shape, see Figure (3). Also, be
sure to not pull the antenna too tight, as you
don’t want the only thing keeping your trees from
swaying is the antenna wire! Secure the ropes to
the supports using a Round Turn and two Half
Hitches, or similar knot.
Figure 3. Installed SKYLOOP antenna.
Connect the Ground.
16. If using a ground, connect it to a ground rod
under the location of the Matching Transformer.
17. Perform operational test.
Troubleshooting
1. Ensure Wire Connectors are securely connected to the Antenna Connections.
2. Inspect Antenna Wire for breakage or signs of strain.
3. Ensure UHF Plug is securely tightened.
4. Inspect Coaxial Cable assembly for cuts in insulation or exposed shielding. Replace if damaged.
5. If still not operational, connect a Standing Wave Ratio (SWR) Power Meter and check SWR.
6. If SWR is greater than 10:1, check antenna tuner or coupler using the technical manual or manufacturer’s
procedure. Be sure to check the Coaxial Patch Cable that connects the radio set to the antenna tuner or
coupler.
7. If still not operational, replace Coaxial Cable assembly. Most problems with antenna systems are caused by
the coaxial cables and connectors.
8. Connect a Multi-Meter to the Antenna Wire to check continuity. Replace assemblies that do not pass a
continuity check.
9. If still not operational, replace Matching Transformer (a).

CHA SKYLOOP (updated February, 2020)
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Specifications
• Frequency: 3.5 –54 MHz (80m through 6m ham bands) - requires a wide range antenna tuner or coupler
• Power: 250 W continuous duty cycle (CW, AM, FM, RTTY), 500W intermittent duty cycle (SSB and SSB-
based digital modes)
• Length: 265 feet wire, 66 ¼ feet each of four sides.
• RF Connection: UHF Plug (PL-259)
• SWR: Subject to frequency, but within limits of most wide range antenna tuners or couplers.
• Weight: 3 lbs.
• Polarization: Horizontal
• Personnel Requirements and Setup Time: one operator, approximately one hour
Accessories
The following accessories are available for purchase from Chameleon AntennaTM. Please contact us at
[e-mail] for current prices and availability.
• Coaxial Cable Assembly. 50 feet of RG-58 with integrated RFI Choke. Used to connect the CHA SKYLOOP
to the radio set. This is a highly recommended accessory if you are not using a CHA RFI CHOKE.
• RF Choke Assembly. The CHA RFI CHOKE will prevent, greatly reduces or totally eliminates the RFI carried
by the coax cable. It can be installed either at the antenna feed point or right behind the antenna tuner.
This accessory is highly recommended if you are not using the Chameleon AntennaTM Coaxial Cable
Assembly.
Recommended non-supplied accessories:
• Wide range antenna tuner or coupler (required for most configurations).
• Polyester or Nylon abrasion-resistant rope (minimum of four lengths of 50 ft each).
Chameleon AntennaTM Products
The following products (and more) are available for purchase at Chameleon AntennaTM.
Go to http://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 P-
Loop 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

CHA SKYLOOP (updated February, 2020)
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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
References
1. Silver, H. Ward (editor), 2013, 2014 ARRL Handbook for Radio Communications, 91st Edition, American Radio
Relay League, Newington, CT.
2. 1987, Tactical Single-Channel Radio Communications Techniques (FM 24-18), Department of the Army,
Washington, DC.
3. Turkes, Gurkan, 1990, Tactical HF Field Expedient Antenna Performance Volume I Thesis, U.S. Naval Post
Graduate School, Monterey, CA.