M25-COIL · Feed Systems & Loading
A matching, loading, feedpoint, transformer, choke, or antenna-interface component.
Why operators make room for it
Put the right RF function exactly where the antenna needs it
A portable radiator can only perform as a system when RF enters it through the right transformer, loading, feedpoint, or common-mode control component.
The CHA M25-Coil is a rugged, high-performance 40-meter loading coil designed to dramatically expand the frequency coverage of your vertical antenna system. It’s the perfect companion for the CHA SS25 25-foot telescoping whip and seamlessly integrates with your MPAS-ready Basic Vertical configuration to create a resonant, quarter-wave, base-loaded vertical antenna on 40 meters .
That gives the operator a controlled way to shape the completed antenna, verify the match at low power, and understand which component limit governs before transmitting harder.
Quick product reference
Key Specifications
- Product type
- Feed Systems & Loading
- Primary role
- A matching, loading, feedpoint, transformer, choke, or antenna-interface component.
- Color
- silver; red
- System requirement
- Use only in a documented antenna configuration
- Power rule
- Observe the lowest published rating of every connected component
- Electrical role
- Feedpoint, transformer, loading, matching, or common-mode-control role is configuration-specific
- Interface rule
- Match every RF connector, thread, conductor, and ground / counterpoise connection
- Tuning requirement
- Verify resonance, SWR, and tuner range in the completed configuration
Operator decision support
Plan the complete setup
See what this product is best suited for, what the documented setup needs, and the boundaries to confirm before deployment.
- Best for
A portable radiator can only perform as a system when RF enters it through the right transformer, loading, feedpoint, or common-mode control component.
- What else you need
Observe the lowest published power rating of every connected component and the duty-cycle limits for the operating mode.
- Compatible with
Match every RF connector, thread, conductor, and ground / counterpoise connection
- Limitations
- Observe the lowest published rating of every connected component
- Match every RF connector, thread, conductor, and ground / counterpoise connection
What an operator can do
- Install the component at the documented feedpoint, loading position, or common-mode control location.
- Observe the lowest published power rating of every connected component and the duty-cycle limits for the operating mode.
- Verify resonance, SWR, tuner range, connector type, and grounding or counterpoise requirements before transmitting.
Complete product details
CHA M25-Coil – 40M Loading Coil for SS25 Vertical
Unlock the Power of 40 Meters with Your Basic Vertical (BV) Setup
The CHA M25-Coil is a rugged, high-performance 40-meter loading coil designed to dramatically expand the frequency coverage of your vertical antenna system. It’s the perfect companion for the CHA SS25 25-foot telescoping whip and seamlessly integrates with your MPAS-ready Basic Vertical configuration to create a resonant, quarter-wave, base-loaded vertical antenna on 40 meters.
Built with serious operators in mind, this coil brings simplicity and performance together—whether you're in the field, on a deployment, or operating under HOA restrictions.
Key Highlights
- Enables 40M Operation: Add the critical 40-meter band to your vertical antenna setup without changing your configuration.
- Bypass Feature: Switch instantly to 30–6M operation with a jumper (jumper not included)—no need to remove the coil.
- Purpose-Built for SS25: Optimized for the CHA SS25 25' telescopic whip for perfect matching and performance.
- MPAS-Ready: Fully compatible with Chameleon Antenna’s Modular Portable Antenna System (MPAS).
- Quick Deployment: Simple, tool-free installation ideal for portable, base, or emergency setups.
Durable and Compact: Built in Nevada, USA for field-grade reliability.
Ideal For
- POTA & SOTA Activators: Take full advantage of the 40M band during Parks on the Air or Summits on the Air activations.
- Emergency Communicators: Ensure reliable 40M coverage in tactical and disaster response operations.
- HOA-Constrained Operators: Add 40M capability to your stealth vertical setup in restricted environments.
- Preppers & Field Operators: Rugged, portable, and versatile—ideal for bug-out bags, go-kits, and mobile operations.
- Amateur Radio Enthusiasts: Upgrade your vertical system for better reach and resonance on a powerful HF band.
Power Considerations for Safe Use
- SSB Mode: Up to 200W for voice communication, which is beneficial for clear, powerful transmissions on lower HF bands.
- CW Mode: Up to 100W, suitable for modes requiring continuous or digital signal transmission. Monitor SWR and reduce power slightly in extreme heat or for extended operation.
Tips for Optimal Performance
- Radials: Always use radials appropriate for the frequency. More and longer radials improve grounding, especially important on 40 meters.
- Environment: Changes in terrain, moisture, and nearby objects may affect tuning. Periodic checks and adjustments can ensure the best SWR.
- Safety: Keep the setup away from people and RF-sensitive equipment, especially when operating above 10 watts.
This versatile setup enables efficient communication across multiple HF bands, whether for emergency, recreational, or portable operations, making the CHA M-COIL a valuable tool in field-deployable antenna configurations.
Made in Nevada, USA | Built to Perform – Wherever You Go
The CHA M25-COIL consists of:
1 X CHA M25-COIL
