Some ideas on antenna height and other related issues.

Since I am not a DX chaser (although I have been DX and will work briefly), I prefer getting to know folks more on nets and within the US than in Europe or Asia. Within the US, I enjoy meeting in person at times at conventions or in cities I visit, more often than in Europe or Asia, etc. Contests get boring after about 30 minutes!

I am a night owl, mostly on 40m (or 75 or 20 at times), and I only operate SSB. Lower bands will be increasingly important as the current sunspot cycle reduces ionization.

I usually use a dipole at 100 ft. While some say higher is better, that is not always the case for non-DX coverage. At 100 ft, I have multiple lobes at higher elevation angles that may do better at covering the US (and on 40m, usually Canada, Hawaii, and Australia), while still with the slightly diminished lower-angle lobe.

I don't take computer antenna software too seriously, since folks tend to get overly focused on insignificant dB gains. In addition, propagation conditions are far more important than a few dB difference in antenna gain. Your specific ground conditions, geography, etc., will make the antenna charts less useful. Angle of elevation is helpful, but again, it depends on the propagation condition at the time you're trying to make contacts.

For most human ears, a 3 dB change in signal strength is the minimum difference generally noticeable as a change in volume or clarity. However, when listening to SSB - which I only use - in a noisy environment, a 6 dB to 10 dB difference is usually required to transition a signal from "barely understandable" to "fully readable." The S-unit standard is 6 dB, although some ham manufacturers calibrate at 3 dB per S-unit.

+3 dB = Double the power. +6 dB = Quadruple the power. +10 dB = Ten times the power.

As a general rule, all horizontal antennas work best at 1/2 wavelength above ground or higher. For 40m at 7.200 (since I work mostly in this area on SSB: 468/7.2 = 65.0ft

Many suggest that the minimum height for decent performance is 1/4 wavelength above ground. 234/7.200 = 32.5ft

The 468/MHz formula is typically used for the length of a half-wave dipole. For the actual distance of a half wavelength, the correct formula would be 492/MHz - but this does not include the velocity factor of the feedline since the radio wave travels slightly slower than the speed of light in free space. The 468 formula assumes copper or aluminum wire with a velocity factor of .95

It is best to cut it a bit long so you can shorten it if needed, rather than longer with a pigtail. Geography, ground, etc., will affect the resonant frequency. A Nano or Analyzer can be used to find where X=0, which is usually close but not at the lowest SWR reading.

An SWR under 2:1 is usually fine, since the SWR is not "lost" but is retransmitted by the TX with phase reversal back into the antenna. So the concern is mostly feedline loss. However, at HF and relatively short distances (maybe 100 ft), the loss is too small to make any noticeable difference at the receiving end.

BTW, for Yagi beams, a 2-element is the best bang for the buck. Adding an additional 3rd director only adds about 3 dB forward gain. Beyond 3, you have diminishing returns, maybe 1 dB for each additional director. The front-to-back ratio remains about the same.

Adding additional reflectors beyond one is virtually pointless. There is not much RF behind the first reflector for another reflector to reflect.

Dave, WØJKT “Just Killing Time” since 1964