BKR wrote:

End fed wires must always be used against an efficient ground system
consisting of a large number of radials or a tuned counterpoise for each
frequency.

A single ground rod is normally fairly poor.

It depends on the length of the wire. If it's near an odd number of
quarter wavelengths long, the radiation resistance between the end and
ground will be low, and a good ground system is necessary to get good
efficiency. If it's significantly shorter than a quarter wavelength, the
resistance is lower yet and a very good system is required. On the other
hand, if it's close to an integral number of half wavelengths, the
resistance will be high, and you can get by with a very poor ground
system -- in many cases just a ground rod -- without sacrificing a
significant amount of efficiency.

That's the reason why a half wave antenna works so well on an HT.

Roy Lewallen, W7EL