Antenna Coloham (often referred to in amateur radio and telecom contexts as a Colinear Ham Antenna or Colinear Omnidirectional Antenna) is a high-gain radio frequency antenna designed to provide 360^\circ horizontal coverage with increased signal strength focused along the horizon.
​Key Technical Features
ₒ ​Colinear Phasing Array: Constructed using multiple stacked dipole elements or co-axial cable sections phased end-to-end inside a fiberglass radome to flatten the radiation pattern.
ₒ ​High Omnidirectional Gain: Delivers high gain (typically 6 dBi to 10+ dBi) compared to a standard 1/4-wave dipole without requiring a directional rotor system.
ₒ ​Low Elevation Angle:
Forces radiated power down toward the horizon rather than into the sky, significantly increasing terrestrial communication range.
ₒ ​Rugged Weatherproof Build: Enclosed in UV-resistant fiberglass tubing with heavy-duty mounting hardware to withstand high winds and harsh weather.
ₒ ​Frequency Bands: Optimized for VHF/UHF amateur radio bands (e.g., 2 Meters / 70 Centimeters) as well as commercial mobile radio frequencies.
​Primary Applications
1. ​Amateur Radio Base Stations: Ideal for radio operators needing broad regional coverage to hit distant repeaters.
2. ​VHF/UHF Repeater Towers: Serves as the central transmitting and receiving antenna for multi-user radio networks.
3. ​Emergency & Tactical Comms: Used in field command posts for maximum area coverage across local emergency services. ​
Quick Comparison: Colinear vs. Standard Dipole

Feature Standard Dipole Colinear (Coloham) Antenna
Gain 2.15dBi 6.0 – 10.0 dBi
Radiation Pattern Broad doughnut shape Flattened disc toward horizon
Physical Height Compact Taller (stacked internal elements)
Coverage 360^\circ Omnidirectional 360^\circ Omnidirectional (Higher Range)