Within the scope of the HB9 course of FACB, we had the opportunity to build our first antenna together with the course participants and lecturers.
This is a multi-band wire dipole "holidays" DX antenna for the 15 m - 20 m - 40 m bands, which can be loaded up to 150 W. No tuner is required, it's possible to switch between the different bands by simply adjusting the total length of the antenna with the help of small built-in jumper plugs.
After the antenna was assembled for the first bandwidth inside the station, it required to be hanged, measured, and adjusted in the yard outside. The wires for the subsequent bands could be attached only afterwards, in iterative cycles. It was fun, but I wish we had a bit better luck with the weather that day... :)
Fellow course participants analyse and adjust their antennas on the campus of the FHNW - Muttenz
It was a great opportunity to try my new RigExpert AA-54 Antenna Analyser as well. The total length of the antenna had to be adjusted for each bands to reach the lowest possible SWR. For the 15 m band, an SWR of 1.1 was quickly achieved exactly in the middle of the band @ 21.225 MHz.
15 m band - couldn't be better
The first trial on the 20m band wasn't too bad either, but further reduction of the total length of the antenna shall improve its characteristics on this second band further.
20 m band - promising
The final antenna consists of 13.9 m coax-cable, 2 x ~3.4 m wire for the 15 m band (red), 2 x ~1.7 m wire for the 20 m band (black), and 2 x ~5.1 m wire for the 40 m band.