Comet GP-15 (6M, 2M, & 440 Band Antenna)
Average price is $170.00 to $200.00
The Comet GP-15 is a pretty cool antenna that really delivers. The GP-15 covers 6 meters, 2 meters, and the 440 band. It uses a very simple design of copper and brass wire sections connected together with a few capacitor traps and couplers, running up through the double reinforced tubular fiberglass shell. There is a small load coil at the base designed to make this antenna very broadbanded.
The basic design of the GP-15 makes it a simple 5/8 wave antenna for 6 meters. At 6 meters, it has just under 1 dB gain over a dipole, so the ERP is about 30% over the input power. That’s better than a 1/2 wave antenna with no gain factor at all. One of the 3 ground radials is a coil loaded 1/4 wave 6 meter radial. But it has a stinger element that can slide in and out of the coil to set the SWR for 6 meters only. This adjustable stinger has no effect on 2 meters or 440 bands.
There are 2 more ground radials that have an interesting effect. These 2 radials are thin steel rods that thread into the hub of the antenna. They are 19 inches long to act as 1/4 wave ground planes for 2 meters. But the length of these 2 radials combined with the stinger radial seem to allow the GP-15 to load up pertty well on the 440 UHF band. If you remove either one of the 3 radials, it no longer loads up on UHF. I thought that was kinda interesting.
The specs for the GP-15 are not bad for a tri-band antenna. Here is how they stack up.
- 6 Meters: 3.0 dBi Gain (0.85 dB/dipole) 5/8 Wave x 1
- 2 Meters: 6.2 dBi Gain (4.05 dB/dipole) 5/8 Wave x 2
- 70 cm: 8.6 dBi Gain (6.45 dB/dipole) 5/8 Wave x 4
- VSWR: 1.5:1 or less
- Max Power: 150 watts FM, 300 watts SSB
- Height: 7′ 11″
- Construction: Double reinforced tubular fiberglass.
- Weight: 3 lb. 1 oz.
- Connector: SO-239
I have owned a GP-15 for almost 9 years, and it has performed wonderfully without any issues. I have made world DX contacts on 6M SSB, always with great reports. I can key 6M repeaters 60 to 75 miles away. My friend and I used to talk 6M FM simplex, and one day we heard some guys start talking to each other. We asked them where they were, and they said they were in their mobiles on the way home from work. We said, but what state are you from. They said they were in South Carolina driving up the highway going home. Keep in mind I am in central PA. They all sounded like they were down the street. We talked to them until each one got home.
Another day we were again on 6M FM Simplex, and one guy keys up giving me a 50dB signal with a VE1 call sign. He said he was in Nova Scotia Canada. I could not believe that 50 dB signal on FM. We all talked for about an hour just rag chewing about anything. Then his signal started to fade slowly untill he was gone. I have talked all over the USA and several SSB DX contacts on 6M with this vertical antenna.
On 2 meters, I hit repeaters up to 80 miles away. I have also hit some stations over 140 miles away on 2M SSB with this vertical tri-band antenna. I have even hit repeaters 70 miles away on 440 UHF. The GP-15 has never failed to surprise me. I doubt you will find a tri-band antenna that can outperform the GP-15. The copy-cat manufacturers have tried, but the closest is a 1/2 wave tri-bander from Diamond, that could never come close to the GP-15.