Hints. Notions. Considerations

Learnt on the way of doing things

d25x2 mm is not enough as a starting element diameter for a 20-meter self-supporting OWA monoband Yagi. At least, d32x2 mm is required
d14x1.2 mm is not enough for 10m and 12m OWA Yagis. 12m Yagi’s elements are nearly in V-shape – not parallel anymore – after a storm. All elements for the 10m Yagi built in the old-fashioned way survived the wind, but the new one – regular d14x1.2-mm tube, bent in V-shape with the tail/reflector wind
A 50x50x2 boom, even with strong supporting guys, is not enough for a 40-meter OWA Yagi. The new Yagi version has a 80x80x4 plus 90x90x4 in the center boom, i.e., 8mm total thickness in the center
Switchable power sources are bad, very bad, and ugly. They may appear OK, when you test. But after sometime, when the temperature change, their operating frequency change as well, and they suddenly produce strong wideband noise on your bands. Use regular heavy transformers and LDO voltage stabilizers

Of course, many cheap Chinese products are inferior quality. However, you can’t even imaging how inferior – plated iron wires instead of copper! As a result – overheating, burnt connectors, cut electricity. Hopefully, no fire but it is not impossible. Beware and double-check before purchasing! See below:

Vibration is killing in the long term. A 20-meter 4-ele Yagi was lost due to that. When it was falling and broke the 15-meter Yagi installed on the same vertical tube. So far, only antennas but it is a very bad and nasty thing in the long-term and invisible destruction of towers can be very dangerous. You thing the connection is good, but it is not; you are loosing elements because loosen after the vibration for weeks, and then just drop; the vibration makes the metal weak by millions of small bents and then the wind breaks the metal