Collection of Amateur Radio Antenna Projects and informations
Friday, April 17, 2026
The New Digital Frontier: Meshtastic vs MeshCore for HAM radio
Building a Quarter-Wavelength Coaxial Collinear Antenna for 2 Meters
For VHF enthusiasts, the Coaxial Collinear antenna remains one of the most practical, compact, and high-gain omnidirectional antennas. It is especially popular for the 2 Meter amateur band (144–148 MHz) because it combines ease of construction with impressive gain and low-angle radiation — ideal for local repeater work and FM simplex operation.
While most builders use half-wavelength sections of coax in traditional Coaxial Collinear antenna designs, the quarter-wavelength COCO offers an interesting alternative that simplifies matching and can be made more compact without compromising much performance. While less common in published literature for the COCO, using λ/4 sections connected with phase-reversing joins can still achieve the desired collinear phasing effect. This is often done by including an initial matching or phasing section that adjusts the impedance and phase relationship for the array.