Collapsible 6-meter Beam Antenna - Design and Performance

Designing a collapsible 6-meter beam antenna involves careful consideration of element geometry and feedline matching, as demonstrated by VE3SMA's project. The construction draws inspiration from foldable dipole concepts and established wire beam designs like the Penn. State 40m beam and the DJ4SA Spiderbeam. Utilizing 4NEC2 modeling, the author optimized element lengths for gain and bandwidth, observing the impact of end loops on resonant frequency and the need for compensation.

Feeding the approximately 25-ohm balanced antenna with 50-ohm unbalanced cable required a specialized network. This setup incorporates a choke balun and a matching section built from two series quarter-wave transformers using readily available 75-ohm cable. On-the-air results validate the design, including a successful 1st double hop Es QSO with 10 Watts and satisfactory performance in the CW WW VHF Contest from FN05, where 41 grids were worked with 100 Watts, showing improved performance over a simple dipole.