This NEC4.2 analysis shows one example of such variation.
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The analyses shown below provide one example of the difference in the radiation patterns of the EFHW system described there.
**RADIATION ENVELOPE at 3.9MHz**
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1$\begingroup$ Would you please consider adding the pseudo-3D picture of the 3.9 MHz pattern that you mentioned, and perhaps also the pictures and impedances for another band or two? $\endgroup$ – rclocher3 May 19 '20 at 15:03
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$\begingroup$ My answer was edited to include the radiation envelope of this system at 3.9MHz. Further analysis of this system is not necessary to illustrate my goal for this answer, which is to show that the radiation pattern of an "EFHW" on its higher bands varies considerably from its pattern when operating on its lowest specified band. $\endgroup$ – Richard Fry May 20 '20 at 8:38
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$\begingroup$ Rich, it may not be necessary for you and I, since we have modeled 80m half-wave antennas on higher bands. But it would help some who have not, if it isn't any trouble. In any case, upvoted. $\endgroup$ – Mike Waters♦ May 20 '20 at 20:33
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1$\begingroup$ I'll give some thought to a more comprehensive analysis of the EFHW configuration, Mike, and may post another Q&A on that topic. $\endgroup$ – Richard Fry May 20 '20 at 21:48
