ml wrote:
interesting , resonant too hmm wonder how the waves look on that dipole?

The free demo copy of EZNEC available from www.eznec.com will
display the current waveform. Here's a copy of a posting I made
to eHam.net

The following results are approximate but show the resonance trend on
80m Vs dipole length. Take a certain length dipole and adjust the length
of the 450 ohm ladder-line for resonance on 7.15 MHz. i.e. NOTE: All of
the following antenna systems are resonant on 7.15 MHz. and cover the
entire 40m band with an SWR of 3.5:1 or less (good for built-in
autotuners). Here are the approximate results:

dipole length : feedline length : resonance on 80m

170' : ~85' : 3.62 MHz (3.52-3.72)

160' : ~87' : 3.7 MHz (3.6-3.8)

150' : ~89' : 3.8 MHz (3.7-3.9)

140' : ~91' : 3.92 MHz (3.82-4)

130' : ~92.8' : 4.06 MHz (resonant out of band)

120' : ~94.7' : 4.23 MHz (resonant out of band)

Yesterday I had a 130' dipole that exhibited the above characteristics.
I have changed it to a 144' dipole and now, with one length of
ladder-line, the antenna covers all of 40m and 200 kHz of 80m using the
limited range autotuner built into my IC-756PRO. A bonus is that the
autotuner also tunes this fixed antenna system on 30m and 17m.
--
73, Cecil http://www.w5dxp.com