From Kraus' 'Antennas', first edition, footnote on page 1:

In its zoological sense, and antenna is the feeler, or organ of touch, of an
insect. According to usage in the United States the plural of "insect
antenna" is "antennae," but the plural of "radio antenna" is "antennas".
However, the usage in England makes no distinction, the plural of both
"insect" antenna" and "radio antenna" being "antennae."


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So for those not native to the USA or England, it depends on where your
English teaher came from, I guess.


Jim
N8EE