Explanation
Overview Directivity describes how strongly an antenna concentrates its radiated energy in one or more preferred directions. An antenna with high directivity focuses more RF energy into specific directions than an omnidirectional antenna. Directivity vs. Gain Although closely related, directivity and gain are not identical. Directivity describes the shape of the radiation pattern. Gain includes both directivity and antenna efficiency. Examples Dipoles have moderate directivity. Yagi antennas have high directivity. Vertical antennas are nearly omnidirectional. Applications DX communication. Weak-signal operation. Contest stations. Point-to-point communication. Applied to Chameleon Products Most Chameleon HF antennas are designed to provide broad coverage suitable for portable, emergency, and general amateur radio operation rather than highly directional communication. Related Articles What Is Antenna Gain? What Is Radiation Pattern? What Is Polarization? Related Products All Chameleon Antennas
The exact result depends on the complete station: frequency, geometry, feed line, matching network, return-current path, environment, operating power, and the reference plane of any measurement. A low SWR establishes an impedance relationship at that point; it does not by itself prove efficiency, radiation pattern, compatibility, or safety.
What to Verify
- Use the newest official product guide or primary service documentation.
- Confirm the exact model, revision, components, configuration, and operating conditions.
- Begin tests at low power and change one variable at a time.
- Do not infer compatibility from connector or thread fit.
Learn Next
- Antenna Selection: A Mission-First Decision Guide
- Engineering Design Tradeoffs in Portable HF Antennas
- Antenna Measurement Reference Planes
- Understanding Common-Mode Current
Source note: Independently synthesized with reference to The ARRL Handbook for Radio Communications, 99th edition (2022), and The ARRL Antenna Book for Radio Communications, 24th edition (2019). Verify changing regulations, services, software, specifications, availability, and safety requirements against current primary sources.
