Mini DeltaAntenna

Demonstrates the design and construction of a compact, portable multi-band mini-delta loop antenna, specifically optimized for /P (portable) operations from remote locations like Scottish islands. The resource covers the theoretical underpinnings of half-wave loops, contrasting closed and open configurations, and then details the application of a folded dipole principle to achieve a 50-ohm match for direct coax feed. It presents empirical formulas for calculating element lengths, considering the velocity factor of common wire types, and provides a detailed example for a 20m (14.175 MHz) version.

The article includes a comprehensive table of dimensions and allowances for a five-band (20m, 17m, 15m, 12m, 10m) mini-delta beam, along with construction hints for the central support and balun. It specifies a 1:1 trifilar balun wound on a ferrite rod and describes the antenna adjustment process using an MFJ-259B Antenna Analyser. Initial test results indicate an SWR of 1:1 at resonance and a bandwidth of approximately 240 kHz on 20m, even at a low height of five feet above ground.

The distinctive utility lies in its focus on a practical, easily deployable beam antenna for portable DXing, offering a viable alternative to more complex or larger arrays.