[TowerTalk] Dipole resonates lower than expected.

[Tom Rauch]

> Wouldn't that be exact 1/2 wavelength of feed line or
multiples, and not 1/4
> wavelength.

No. The scalar reactance value repeats every 1/4 wl even
though the sign inverts.

So if I have 30 J0  with 1/4 wl of low loss coax  I'll have
a different R but still J0.  With a 50 ohm lossless line I'd
have 30 J0 at 1/2 wl, and 83.3 j0 with 1/4 wave.  In either
case I'd have resonance indicated correctly.

If the line was some length other than an exact 1/4 wave
multiple it would modify reactance and shift the antenna
frequency. Since the AEA analyzer only takes an educated
guess at reactance sign and under some conditions will guess
wrong, we have to be careful using a Smith chart to
determine impedance at the antenna.

73 Tom