GAP Antenna Products
| GAP Antenna Products | |
|---|---|
| Type | Private company (GAP Antenna Products, Inc.) |
| Founded | About 1990 |
| Headquarters | Florida, United States |
| Amateur radio | |
| Known for | Multiband HF verticals fed at an elevated gap, needing no radial field |
| Status | Active |
| Website | gapantenna.com |
GAP Antenna Products is an American maker of multiband HF vertical antennas, based in Florida. Its antennas, such as the Titan DX and Voyager DX, look like ordinary ground-mounted verticals but work as vertical dipoles fed at an insulated gap partway up the mast. Because of this they do not need a field of buried radials, one of the main chores of installing a conventional vertical.
History
GAP Antenna Products, Inc. has served the amateur radio market since about 1990; its website describes the company as celebrating 35 years in the hobby. Its antennas were already familiar to hams by the mid-1990s, when user groups collected notes and modeling results on how the design behaves. Sources reached for this article do not name the founder, and no changes of ownership have been reported.
Besides selling from its own website, the company has its antennas carried by dealers in Europe. As of 2026 its website lists four antenna models along with accessories and spare parts.
How the antennas work
A typical ground-mounted vertical is a quarter-wave monopole, and the earth or a radial system forms the other half of the antenna. A GAP vertical instead is an asymmetric dipole standing on end. The coaxial feed line runs up inside the lower part of the mast to an insulated gap, where it connects between the upper and lower sections. The company describes this as an "elevated feed".
The lower mast section and a short counterpoise of a few wires near the base make up one half of the dipole, so the antenna does not depend on ground losses in the way a quarter-wave vertical does. On 80 meters, matching is handled by a coax stub inside the upper tubing, with a plug-in capacitor that sets which part of the band is matched. For the higher bands, open-wire "linear decoupler" stubs run along the outside of the mast and isolate parts of the radiator instead of traps. On some models a coiled counterpoise wire at the base also acts as a quarter-wave element on 40 meters.
The company states that its antennas need no traps, coils, tuning or tuner, change bands automatically, present a nominal 52-ohm impedance and handle high power. Power ratings vary by model and band; dealer listings for the Titan DX, for example, give a lower rating on 80 meters than on the higher bands.
Products
- Titan DX: about 25 feet tall, covering eight bands from 80 through 10 meters.
- Voyager DX: about 45 feet tall, aimed at the low bands with coverage of 160, 80, 40 and 20 meters.
- Challenger DX and Eagle DX: other multiband models, the Eagle covering six bands from 40 through 10 meters.
- Accessories: guy kits, a tilt-over ground mount, replacement counterpoise assemblies, single-band "Mono GAP" kits and the capacitor units used to select the operating segment.