This is part II for 4 element 6m yagi. Part I is about metal parts. Here is some brief description about electrical connection and preliminary test.
4. Antenna feed
To finish the antenna few parts must be 3D printed (or produced with other materials, like plastic pipes). Holder for air coil consists of three parts: coil holder, coil support and connector holder.
Coil holder is simple cylinder (pdf drawing: chokeholder), which is long enough to accommodate 12 turns of RG58 or similar cable:
Second part for the coil is distancer (pdf drawing: chokedistancer), which fixes coil to the antenna construction:
Third part is connector mount (PDF drawing: connectormount):
The cable is wound on the holder and fixed with the distancer. Next, the connector is mounted to its plate and the coil is connected between the dipole and connector. Finally, the dipole connection is protected with the cover (from part I).
All feed elements are then assembled to the antenna construction:
And here’s the completely assembled antenna:
First preliminary testing was done with VNA CAT (Cable/Antenna Test). The VSWR diagram without any tuning is shown in following diagram:
Live testing report will follow after making some QSOs.