The Comet GP-9 is one of the most respected high-gain dual-band base antennas available to amateur radio operators. Engineered for 2-meter and 70-centimeter bands, it delivers outstanding performance, durable construction, and reliable signal reach. When you’re setting up a permanent base station or upgrading your current antenna system, the GP-9 offers a significant boost in coverage and clarity.
Let’s explore how it works, its specifications, performance benefits, and why it stands out in the world of VHF/UHF base antennas.
How the Comet GP-9 Works
The GP-9 functions as a collinear phased array antenna. Inside, multiple elements are stacked vertically, using phasing coils to align signals in-phase. As a result, the antenna radiates energy in a compressed vertical pattern. This increases horizontal reach and range while reducing wasted energy toward the sky or ground.
Moreover, this design delivers higher gain without the need for large horizontal beams or rotators. It’s a fixed omnidirectional antenna, meaning it radiates equally in all horizontal directions, perfect for covering broad areas.
Performance and Gain
The Comet GP-9 is a super high-gain antenna, optimized for long-distance communication. It boasts:
- Gain of 8.5 dBi on 2 meters
- Gain of 11.9 dBi on 70 centimeters
These figures translate into significantly improved range compared to lower-gain verticals. For instance, hams using repeaters or working simplex will notice a clear boost in signal strength and reception distance.
Additionally, the antenna maintains excellent VSWR performance, typically 1.5:1 or better across both bands. This reduces transmission losses and protects your equipment from reflected energy.
Construction and Durability
One of the key selling points of the GP-9 is its rugged construction. Built to withstand harsh weather, this antenna uses high-quality fiberglass for the outer radome and stainless steel for all critical mounting hardware.
Its three-piece design allows for easier transport and installation, especially in areas with height restrictions. Furthermore, once assembled, the joints lock tightly, ensuring mechanical stability even in high winds.
The antenna is rated for winds up to 134 MPH (60 m/s), and its maximum power handling is 200 watts, making it suitable for most base station transceivers.
Full Specifications
- Frequency Range: 144–148 MHz (2m), 430–450 MHz (70cm)
- Gain: 8.5 dBi (2m), 11.9 dBi (70cm)
- Power Rating: 200 watts
- VSWR: Less than 1.5:1
- Length: 14.5 feet (4.4 meters)
- Weight: 4.5 lbs (2 kg)
- Mounting Hardware: Included (U-bolts for 1.25″–2.5″ mast)
- Connector Type: SO-239 (UHF Female)
- Construction: Heavy-duty fiberglass, stainless steel hardware
- Wind Rating: 134 MPH (no ice)
- Number of Radials: 3 counterpoise radials (UHF), non-ground plane dependent
Features and What They Do
1. Collinear Phased Elements
These internal elements stack signal radiation vertically, focusing energy outward for extended horizontal coverage. Consequently, this improves simplex and repeater performance significantly.
2. Fiberglass Outer Shell
The antenna is enclosed in a durable fiberglass radome. This material resists UV radiation, moisture, and mechanical stress, increasing the antenna’s lifespan.
3. Omnidirectional Radiation Pattern
You don’t need to rotate this antenna. It radiates evenly in all horizontal directions, making it ideal for emergency comms, nets, or busy repeater zones.
4. High Wind Resistance
With its low flex and rugged mounting system, the GP-9 can endure high wind loads, making it suitable for rooftop and tower installations.
5. Dual-Band Design
It operates seamlessly on both 2 meters and 70 centimeters without requiring any adjustments or tuning. Therefore, it’s compatible with all standard dual-band radios.
6. SO-239 Connector
A standard connector for amateur base antennas, it supports various coaxial cables and ensures a secure, low-loss RF connection.
Advantages of the Comet GP-9
- Superior Range: The high gain ensures your signals reach farther and are received more clearly.
- Durable Design: It withstands outdoor elements for years with minimal maintenance.
- No Tuning Required: Factory tuned to operate efficiently right out of the box.
- Simple Setup: Even though it’s tall, the three-piece design allows for quick installation.
- Lightweight for Its Size: At just 4.5 lbs, it’s easy to handle despite being over 14 feet long.
- Versatile Mounting: Works on towers, masts, or rooftops with the included U-bolt hardware.
- Perfect for Emergency and Repeater Use: The wide coverage makes it excellent for ARES, SKYWARN, or club repeaters.
Furthermore, the GP-9 performs exceptionally well even in suburban or rural areas where elevation and open space can be leveraged.
Final Thoughts
The Comet GP-9 is a powerhouse antenna for any ham who wants strong, reliable performance on VHF and UHF. Its high gain, rugged build, and plug-and-play operation make it a favorite among operators who demand the best from their station setup.
Although taller than entry-level antennas, the benefits of increased range, signal quality, and robust weather resistance far outweigh the extra installation effort. Ultimately, the GP-9 is an excellent investment for hams looking to take their station’s performance to the next level.