With all the hoopla going on for this antenna I was surprised that no
one reported any calculated antenna efficiencies. So I modeled the
antenna in free space - to remove environmental influences other than
those contained within the antenna itself (terminating resistor and
wire loss) - NEC reported the following:

Freq. MHz. Efficiency Average Gain Peak Gain
MHz % DBi DBi

3.5 9.6 -10.43 -8.49
7.15 41.24 -3.85 -1.33
14.2 23.21 -6.36 -1.59
21.2 30.01 -5.23 -1.36
29 53.81 -2.69 2.17

73
Danny, K6MHE

Freq. MHz. Efficiency Average Gain Peak Gain
MHz % DBi DBi

3.5 9.6 -10.43 -8.49
7.15 41.24 -3.85 -1.33
14.2 23.21 -6.36 -1.59
21.2 30.01 -5.23 -1.36
29 53.81 -2.69 2.17

73
Danny, K6MHE


80M is a bit lower than I expect, but not by much:referring to dBmax values. It
probably picks up a dB or more at the high end of 75M.

It doesn't mean much to discuss 'average gain' values unless its an isotropic
or (within a certain elevation range) an omni antenna. Sometimes vertical
dipoles are described as having an 'average gain', but I haven't seen that
used for horizontal ones:-)

The pattern is not bidirectional on the higher bands BTW... ar least that's
what intuition tells me...

73,
Chip N1IR