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[W1VT]

March 1936 QST
W3EDP experimentally came up with 84ft against a 17ft counterpoise via trial and error.
Link coupling to a coax feeder.

[K1KIM]

w5alJ

USing a w9:1 transformer the lengths are not precise but there are lengths that make
for easier use with a tuner.

Lengths like 53, 59, 88 and 124 are often listed as good.

NOTE:  you must use a counterpoise (second wire on the ground side to complete
the antenna) with that or you will have massive RF in the shack.  Length for that
varies with band but safe start is 1/4 wave for the lowest frequency.

Allison

A 60' counterpoise for a 80-10M EFHW of 123' seems excessive. Many are using 15'-20' counterpoise with a 49:1 UNUN.

[N4UFO]

9:1 transformer [/u]

A 60' counterpoise for a 80-10M EFHW of 123' seems excessive. Many are using 15'-20' counterpoise with a 49:1 UNUN.

Not the same thing. I've played with both, definitely use far different counterpoises. The 9:1 needs one to balance overall length of what is often a 1/4 wave antenna and an EFHW needs maybe 10% of what is essentially a half wave antenna.

That said, I have a 160m EFHW and one might say it has either no counterpoise (the way the transformer is wired), 1.5-2.0 feet (the metal post the transformer is mounted on) or ~88 feet (buried coax length to a common mode choke) depending on what you consider a counterpoise.