Chameleon Antenna CHA PRV Portable Resonant Vertical Antenna

Introduction

Thank you for purchasing and using the Chameleon Antenna™ Portable Resonant Vertical (CHA PRV) antenna. The CHA PRV is a finely crafted, lightweight, and rugged antenna designed for extreme portable use, such as Parks On the Air (POTA), Summits On the Air (SOTA), and other outdoor radio adventures where an efficient but highly portable antenna is required. It is also ideal for radio enthusiasts living in an RV, apartment, or condominium with limited balcony or patio space. Chameleon Antenna™ designed the CHA PRV to complement the new generation of small multi-band/multi-mode QRP transceivers, including models like the Icom IC-705, Xiegu G90 or X6100, LAB 599 TX500, or the Yaesu FT-817/818.

The CHA PRV antenna operates from 5.4 – 100.0 MHz continuous and covers the 40 – 2 meter Amateur Service bands without an antenna tuner. Tuning the CHA PRV is straightforward; simply adjust the height of the Multi-Configuration Coil when changing bands on 40 through 10 meters.

The PRV SOTA (LIGHT KIT) includes the Multi-Configuration Coil, a telescoping 58-inch stainless steel whip, a ground Spike Mount, a Puck Hub, four 12.5 ft. radial wires with line winders, a Variable Length Counterpoise, a Camera Tripod Adapter, and 12 ft. of RG-58 coaxial cable with an integrated RF choke.

The PRV POTA (HEAVY KIT) contains all components of the PRV SOTA kit, plus the Universal Clamp Mount and two 12-inch Extender Rods to elevate the antenna base for improved performance.

The CHA PRV is designed for modularity and can utilize components and accessories from the popular Modular Portable Antenna System (MPAS) 2.0 and MPAS Lite antenna systems. It offers flexible mounting options, including the included Spike Mount for ground mounting, or it can use the Universal Clamp Mount or Jaw Mount to attach to picnic tables, balcony railings, fence posts, or other convenient support structures.

Using the Camera Tripod Adapter, the CHA PRV can be mounted to a heavy-duty camera tripod or monopod. This antenna does not require an antenna tuner when properly tuned. Chameleon Antenna™ antennas are known for being versatile, dependable, stealthy, and built to last. Reading this operator's manual will help you maximize the utility of your CHA PRV.

Safety Warning: Be aware of overhead power lines when deploying the CHA PRV. Electrocution is possible if the antenna gets near or contacts overhead power lines.

Note: Photographs and diagrams in this manual may vary slightly from current production units due to manufacturing changes that do not affect the product's form, fit, or function. All information is proprietary to Chameleon Antenna™. Specifications are subject to change without prior notice.

HF Propagation

HF radio offers inexpensive and reliable local, regional, national, and international voice and data communication. It is particularly useful in undeveloped areas where telecommunications are unavailable, costly, or scarce, or where infrastructure is damaged by disasters. HF radio wave propagation is influenced by weather, terrain, latitude, time of day, season, and the 11-year solar cycle.

HF radio waves propagate via two methods: ground waves and sky waves.

Ground waves consist of direct and surface waves. Direct waves travel line-of-sight, typically 8 to 14 miles for field stations. Surface waves follow Earth's curvature beyond the radio horizon, usable up to about 90 miles under optimal conditions. Factors like low power, horizontal polarization, terrain, foliage, or dry soil can significantly reduce ground wave range.

Sky waves are the primary HF propagation method. HF radio waves below the critical frequency are reflected by the ionosphere back to Earth, covering distances from 300 to 2,500 miles. Multi-hop propagation occurs when waves reflect off Earth back to the ionosphere. Key concepts for operators are Maximum Usable Frequency (MUF), Lowest Usable Frequency (LUF), and Optimal Working Frequency (OWF).

The MUF is the frequency predicted for 50% success on any given day in a month. The LUF is the frequency below which communications fail due to ionospheric losses. The OWF, between LUF and 80% of MUF, is the range for reliable communication. If LUF exceeds MUF, sky wave propagation is unlikely.

Operators can estimate MUF and LUF by listening to band activity. Propagation prediction software, like the Voice of America Coverage Analysis Program (VOACAP) at www.voacap.com, can predict success rates based on location and time. ALE (Automatic Link Establishment) is an automated method for finding OWF frequencies.

There's a gap between ground wave range (40-90 miles) and the first sky wave hop (around 300 miles). Near Vertical Incidence Skywave (NVIS) propagation can fill this gap, typically using frequencies from 2 to 10 MHz (2-4 MHz at night, 4-8 MHz during the day). The CHA PRV, like most vertical antennas, is not designed for NVIS propagation.

CHA PRV SOTA Kit Components

The CHA PRV SOTA kit comprises the following components:

A. Multi-Configuration Coil (CHA MCC): Provides base-loaded inductance for the vertical antenna and is continuously adjustable for resonance at the operating frequency.

B. Telescoping Whip: The radiator for the vertical antenna. Made of stainless steel, it is 58 inches long when extended and 17 1/2 inches long when collapsed.

C. Coaxial Connector: An SO-239 socket on the side of the Multi-Configuration Coil used to connect the Coaxial Cable.

D. Tuning Tube: A movable cover over the loading coil that adjusts impedance by moving up or down, thereby changing the antenna's resonant frequency.

E. Lock Knob: Used to secure the Tuning Tube in place once resonance is achieved.

F. Coaxial Cable: A 12-foot RG-58 cable with an integrated RF Choke, used to connect the CHA PRV to the radio set. Longer lengths are available. This antenna requires an RF Choke in the feedline.

G. Spike Mount: Drives into the ground to provide a ground mount for the CHA PRV.

H. Counterpoise Wire: The basic antenna includes four 12.5 ft. Counterpoise Wires.

I. Camera Tripod Adapter: Used to mount the CHA PRV to a camera tripod, monopod, or trekking pole. It features a 3/8 in. x 24 threaded socket for the MCC base and a 1/4 in. x 20 threaded socket for the camera tripod.

J. Counterpoise Connector: A banana-style plug at the end of the Counterpoise Wire, used to connect it to the Puck.

K. Puck (CHA PUCK): A hub that connects up to six Counterpoise Wires to the antenna.

L. Line Winders: Used for storing the Counterpoise Wires.

M. Stakes: Used to anchor the far ends of the Counterpoise Wires to the ground.

N. Insulator Ring: Located at the end of each Counterpoise Wire.

O. Variable Length Counterpoise: A flexible method for providing the CHA PRV with a necessary counterpoise from 5.3 to 54.0 MHz (60 – 6 meters).

Diagram Description (Plate 2): A visual display of the main antenna components, labeled A through G, showing the Multi-Configuration Coil, Telescoping Whip, Coaxial Connector, Tuning Tube, Lock Knob, Coaxial Cable, and Spike Mount.

Diagram Description (Plate 3): A visual display of the counterpoise system components, labeled H through O, including Counterpoise Wires, Connectors, Puck, Winders, Stakes, Insulator Rings, and the Variable Length Counterpoise.

CHA PRV POTA Kit Components

In addition to the SOTA kit components, the CHA PRV POTA kit includes:

P. CHA UCM (Universal Clamp Mount): A heavy-duty clamp-style mount for use on balcony railings, tables, and other fixtures with flat horizontal surfaces. It is suitable for semi-permanent installation.

Q. 12 In. Extender Rods: Two 12-inch rods installed below the MCC and Puck hub to raise the antenna base by 24 inches, improving performance.

Diagram Description (Plate 4): Shows the additional components for the CHA PRV POTA kit: the Universal Clamp Mount (P) and the 12 Inch Extender Rods (Q).

Ground Spike Mount Setup

Setting up the CHA PRV with the ground Spike Mount is quick and easy. Follow these steps, referring to Figure 1:

Caution: Do not attempt to drive the assembled antenna into the ground by grasping the Multi-Configuration Coil or striking its top, as this can cause permanent damage. Instead, drive the Spike Mount into the ground first, then assemble the components onto it.

1. Select a site large and clear enough for the antenna and counterpoise wires.
2. Using a plastic hammer or rubber mallet, drive the Spike Mount (G) into the ground at the center of the site.
3. Thread the Puck (K) hub onto the stud at the bottom of the Multi-Configuration Coil (A), tightening hand tight. The side with the indentation is the top.
4. Thread the Multi-Configuration Coil stud onto the Spike Mount, tightening hand tight.
5. Thread the stud on the bottom of the Telescoping Whip (B) into the socket on top of the Multi-Configuration Coil, tightening hand tight. The completed assembly should resemble Plate 5.
6. Fully extend the Telescoping Whip.
7. Insert a Counterpoise Connector (J) at the end of a Counterpoise Wire (H) into an empty socket on the side of the Puck hub.
8. Unwind the Counterpoise Wire from its Line Winder (L).
9. Extend the Counterpoise Wire in a reasonably straight line away from the antenna.
10. Place a Stake (M) through the Insulator Ring (N) at the end of the Counterpoise Wire.
11. Drive the Stake into the ground where the end of the Counterpoise Wire is located.
12. Repeat steps 7-11 for the remaining Counterpoise Wires.
13. Connect the end of the Coaxial Cable (F) nearest to the RF Choke into the Coaxial Connector (C) on the bottom of the Multi-Configuration Coil. (This antenna requires coaxial cable with an RF Choke).
14. Connect the other end of the Coaxial Cable to the radio set.
15. Perform an operational check as described in the "Operation of the Portable Resonant Vertical" section.

Diagram Description (Figure 1): Shows the CHA PRV Ground Spike Mount setup with Overhead View and Side View. The Side View illustrates the antenna, radials, stakes, and Puck Hub connected to the Spike Mount. The Overhead View shows the radial pattern.

Diagram Description (Plate 5): A photograph illustrating the bottom assembly of the antenna, showing how the main components connect.

Operation of the Portable Resonant Vertical

Tuning the CHA PRV on 40 through 10 meters is achieved by adjusting the height of the Multi-Configuration Coil and selecting the number of Counterpoise Wires. Follow this procedure:

1. For operation on 40 to 10 meters, ensure the Telescoping Whip is fully extended.
2. Connect or disconnect Counterpoise Wires to match the "Number of Radials to Use" column in Table 2 for the specific operating band.
3. Set the initial tuning height of the Multi-Configuration Coil according to the "Initial Coil Height" column in Table 2 for the operating band. For non-ground-mounted setups, use Table 3 for initial settings. Height is measured in centimeters (cm) from the bottom of the Tuning Tube (D) to the bottom of the loading coil, as shown in Plate 5. Fine-tuning can also be done by moving the Tuning Tube UP or DOWN for maximum received noise, though this is less effective due to body capacitance.
4. To adjust the height, loosen the Lock Knob (E), grasp the Tuning Tube, and gently move it UP or DOWN. You will feel a "bump" as the Tuning Tube moves between coil windings, indicating fine-tuning.
5. Use the Tuning chart (Figure 2) to adjust the CHA PRV for resonance. The chart guides you to find the dip in SWR (ideally below 2.0:1) on 40 through 10 meters by adjusting the Multi-Configuration Coil height.
6. Tighten the Lock Knob finger tight; do not overtighten.

If you observe only a shallow dip in SWR at resonance, reduce the number of Counterpoise Wires. The Tuning Tube may also require a slight adjustment (one "bump") up or down. Shortening Counterpoise Wires increases the resonant frequency, while lengthening them decreases it.

Note: Antenna height, counterpoise wire length and position, ground conductivity, and body capacitance can affect antenna resonance. The initial settings in Tables 2 and 3 are for typical environments and may vary.

Diagram Description (Plate 5): A close-up view of the tuning adjustment mechanism on the antenna, showing the Lock Knob and the Tuning Tube with indicators for "Up" (Increases Height, Lowers Frequency) and "Down" (Decreases Height, Raises Frequency).

Diagram Description (Figure 2): A flowchart illustrating the tuning process for 40-10 meters. It guides the user through adjusting the Tuning Tube based on SWR readings to achieve resonance, indicating steps like "Move Tuning Tube UP 1 Bump" or "Move Tuning Tube DOWN 2 Bumps" and checking if SWR is less than 2.0:1.

Operation on 6 and 2 meters

The CHA PRV can be used on the 6 and 2 meter ham bands. To operate on these bands:

• Fully lower the Multi-Configuration Coil.
• For 6 meters, install one or more Counterpoise Wires that are ¼ wavelength long, or use the optional Stinger Kit.
• Lower the Telescoping Whip to the length specified in Table 4.
• Make fine adjustments to the Telescoping Whip length until the SWR is less than 2.0:1.

Tuning Theory

Unlike many portable antennas with broadband designs, the CHA PRV is a resonant antenna. Resonance occurs when Reactance (X) is zero and Impedance (Z) is purely Resistive (R). The key benefit of a resonant antenna is the elimination of the need for an antenna tuner, which is advantageous for portable operations like POTA and SOTA.

Understanding resonance is crucial for quick tuning. Figure 3 illustrates possible initial tuning regions as seen on an antenna analyzer. Region (1) indicates the antenna is too long (high SWR, asymptotic), while Region (4) indicates it is too short (high SWR, asymptotic). Regions (2) and (3) represent approaching resonance.

Without an analyzer, determining the exact region is difficult, but the tuning procedure will eventually lead to resonance. Testing showed that a maximum of seven iterations were needed to achieve an SWR below 2.0:1, with a minimum of three. The goal is an SWR less than 2.0:1, indicating proximity to resonance. If starting in Regions (1) or (4), record the final height for future reference.

Diagram Description (Figure 3): An SWR graph showing different tuning regions. Region 1: SWR very high, antenna too long. Region 4: SWR very high, antenna too short. Regions 2 & 3: Approaching resonance. The graph also shows a sample measurement of "Min.: 1.28 at 14.09 MHz".

Recovery Procedure

To pack up the CHA PRV, follow these steps:

1. Disconnect the Coaxial Cable from the radio set and antenna.
2. Carefully roll (do not twist) the Coaxial Cable.
3. Unplug the Counterpoise Wires from the Puck hub.
4. Pull the Stakes from the ground.
5. Wind the Counterpoise Wires onto their individual Line Winders.
6. Collapse the Telescoping Whip and remove it from the Multi-Configuration Coil.
7. Detach the Multi-Configuration Coil from the Spike Mount. The Puck hub can remain attached.
8. Pull the Spike Mount from the ground.
9. Check the deployment area for any misplaced antenna components.
10. Remove dirt from antenna components and inspect them for wear.
11. Store components together in a tactical pack.

Troubleshooting

1. Ensure the Telescoping Whip, Multi-Configuration Coil, Puck hub, Coaxial Cable, and Counterpoise Wire connections are secure.
2. Verify the correct number and length of Counterpoise Wires are used. Too many or too long wires can result in an SWR greater than 2.0:1, even at resonance.
3. Inspect antenna components, especially the Coaxial Cable, for breakage or strain. Replace damaged components.
4. Check any patch cables or adapters used.
5. If the antenna is still not operational, connect a Standing Wave Ratio (SWR) Power Meter and check the SWR.
6. If the SWR remains greater than 5:1 after tuning, replace the Coaxial Cable assembly. Coaxial cables, connectors, and adapters are common sources of problems.
7. If issues persist, contact Chameleon Antenna™ for technical support.

Modular Upgrades

The CHA PRV is designed to be modular, accepting optional accessories developed specifically for it, as well as existing components and accessories from other Chameleon Antenna™ products. These upgrades enhance the utility of Chameleon Antenna™ products and are available for purchase at www.chameleonantenna.com or from dealers.

Variable Length Counterpoise System

This system offers a flexible method for providing the CHA PRV with a necessary counterpoise from 5.3 to 54.0 MHz (60 – 6 meters). Used with the Puck hub, it is an excellent upgrade for MPAS 2.0 or MPAS Lite antennas. It includes 34 ft. of high-visibility light gauge wire that can be placed on the ground or elevated. Figure 4 illustrates the crank reel in an elevated configuration using a trekking pole and paracord suspension line for rapid adjustment of counterpoise length.

To use the Variable Length Counterpoise with the CHA PRV:

1. Fully extend the Counterpoise Wire.
2. Tune the CHA PRV using the "Operation of the Portable Resonant Vertical" procedure.
3. If the SWR is greater than 2.0:1, shorten the Counterpoise Wire by cranking or rolling in several feet and try again. Repeat until SWR is less than 2.0:1. A shallow dip in SWR at resonance indicates the Counterpoise Wire is too long. The Tuning Tube may also need a slight adjustment (one "bump") up or down, as shortening the wire increases resonant frequency and lengthening it lowers it.

Diagram Description (Figure 4): Depicts various setup methods for the Variable Length Counterpoise, showing configurations with a camera tripod, trekking pole, and ground placement.

Other Whips and Kits

CHA MIL 2.0 WHIP

• Type: Military-style collapsible whip antenna.
• Frequency: Approximately 5 to 22 MHz continuous (60 - 15 meter ham bands) when used with the CHA PRV.
• Length: 9 ft. 4 in. extended, less than 20 in. collapsed.
• Color: OD Green.
• Description: Based on designs used globally by armies, this antenna is part of the Modular Portable Antenna System (MPAS) 2.0, enabling 60-meter operation and improving performance on 40 through 15 meters.

CHA SS17

• Type: Stainless Steel telescoping whip antenna.
• Frequency: Approximately 4 to 14 MHz continuous (60 - 30 meter ham bands) when used with the CHA PRV.
• Length: 17 ft. extended, 27 in. collapsed.
• Color: Chrome.
• Description: A sturdy 10-section telescoping whip, longer than the standard 58-inch whip. It is part of the MPAS Lite system, enabling 60-meter operation and improving performance on 40 and 30 meters.

Stinger Kit

The Stinger Kit provides a rigid ground plane of six 4 ft. rigid radials and a 48-inch rigid whip "stinger." It's ideal for use with the CHA PRV when space is limited for longer counterpoises or the full 58-inch Telescopic Whip. It's perfect for RVs or apartment balconies, enabling operation on 7.0 through 54.0 MHz (40 through 6 meters). A tuner may be needed on 40 meters. The 58-inch Telescopic Whip must be collapsed to the correct length for 6-meter operation.

Diagram Description (Figure 5): Illustrates the Stinger Kit setup with Overhead View and Side View, showing rigid radials and the stinger whip attached to the antenna base.

Mounts and Adapters

Jaw Mount (CHA JAWMOUNT)

A portable clamp-style mount capable of attaching to various objects like fence posts, poles, tables, and ladders. It is ideal for mounting the CHA PRV to a picnic table during POTA activations.

Camera Tripod Adapter

An optional product enabling any Chameleon Antenna™ with a 3/8" x 24 mount to attach to a heavy-duty camera tripod or monopod. This setup is considered ideal for hiking and SOTA operations.

Universal Clamp Mount (CHA UCM)

A heavy-duty clamp-style mount intended for use on balcony railings, tables, and other fixtures with flat horizontal surfaces with edges. It is suitable for semi-permanent installation. The CHA PRV with the Stinger Kit is ideal for RVs, apartments, or condominiums.

Accessories

In addition to the modular components, the following accessories are available from Chameleon Antenna™:

• COIL LOCK: A device to support the added weight and momentum of the CHA SS17 17 ft. telescoping whip when used with the CHA PRV antenna.
• CHA DPACK: A small to medium-sized pack perfect for storing the CHA PRV components and other portable station equipment for your next deployment.

Specifications

• Frequency Range: Covers 40 – 2 meter Amateur Service bands. No tuner required. Approximately 5.4 MHz through 37.0 MHz continuous as a base-loaded quarter wave with the 58 in. Telescoping Whip fully extended and tuned by adjusting the Multi-Configuration Coil height. Approximately 37.0 through 100.0 MHz continuous with the Multi-Configuration Coil fully down, tuning adjusted by varying the Telescoping Whip length. 144.0-148.0 MHz as a base-fed half wave.
• Power Handling: 500W intermittent Duty Cycle (SSB Phone), 300W all other modes.
• Height: Approximately 80 inches fully assembled / extended.
• SWR: Typically, less than 2:1 at resonance.
• Bandwidth: See tables (2) and (3).
• Weight: Approximately 3 lbs.
• Color: Mostly green with a stainless steel whip.
• Setup Time: One operator, approximately 10 minutes.

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.

Chameleon Antenna™ Products

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