End Fed Half Wave Experiment – Part 1, End Fed Half Wave Experiment – Part 2 The “Tune-up-ening”
The first attempts to tune up the real antenna did not go well. I found from the trap dipole project attaching the wires beyond the trap was needed to get the higher bands tuned properly. This worked against me here. With the high impedance on the end fed I was better off tuning the 40m antenna segment without the coil and 80m tail attached. Unfortunately, I wasted a lot of time experimenting/snipping before I decided to detach the inner antenna from the coil.
Once taking that step, I found I had probably trimmed too much off. Tuning for 40m without the coil proved simple enough. After that the other bands were easier too. I was also able to re-attach the coil and 80m tail, and find tap settings and tail lengths to allow operation with good matches on 80m and 20m. With the 20m tails attached 40m operation on the upper edge is possible. With tails 40m SWR was a bit high on CW segment, although possible with a tuner. 10m seemed unaffected by the coil and tail. 15m provided low SWR only with the coil and tail detached, but SWR of 2:1 up to 3:1 with 80m coil and tail.
Antenna Stuff
The coil as wound measured out to 77.5uh, resonant at 3.85Mhz with 22pf of capacitance. It is ~63 close-wound turns on a mystery plastic coil form of ~2 […]
Continue reading End Fed Half Wave Experiment – Part 3