Comet GP-9 / GP-9N
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| Frequency | 144-148 MHz, 430-450 MHz |
| Gain | 8.5 dBi |
| Modes | FM, SSB, CW, digital |
| Connector | SO-239 |
| Year | 2005 |
| feedpoint | SO-239 |
Comet's highest-gain dual-band base collinear: 8.5 dBi on 2m (5/8 wave x 3) and 11.9 dBi on 70cm (5/8 wave x 8). A heavy-duty 3-section fiberglass radome, available with SO-239 (GP-9, GP-9M) or N-female (GP-9N) for better UHF signal transfer. 200W SSB / 100W FM, with extruded aluminum and stainless steel mounting hardware included. Many are in use as repeater antennas.
16 feet 9 inches of fiberglass in the wind needs a sturdy mount. 92 mph wind survival is not for extreme mountaintop sites. The very low radiation angle can miss nearby stations in hilly terrain (Comet suggests the GP-6 for mountainous areas). A 3-section assembly. Radome joints can develop cracks over years.
Comet's highest-gain dual-band base antenna. The GP-9 suits repeater operators, APRS iGate stations, and installations where maximum range matters. It competes with the Tram 1481 and Diamond X-510 class.
The Comet GP-9 is one of the highest-gain dual-band base antennas available for the 2-meter and 70-centimeter amateur bands, a tall fiberglass collinear vertical built for maximum coverage from a fixed station. At about 16 feet 9 inches it delivers roughly 8.5 dBi of gain on 2 meters and a strong 11.9 dBi on 70 centimeters, putting it in the top tier of single-stick VHF/UHF base verticals.
It is a rugged three-section fiberglass design rated to survive high winds, handling up to 200 watts on SSB and 100 watts on FM, with a low SWR across both bands. The standard GP-9 uses an SO-239 connector while the GP-9N variant uses a Type-N. As with any high-gain vertical the radiation pattern is flattened toward the horizon, which maximizes reach to distant repeaters but can work against you for stations sharply above or below your elevation.
It is a current product and Comet's flagship dual-band base vertical. It competes directly with the high-gain Diamond X700HNA, while the Diamond X300A is a shorter mid-gain alternative.