Anyone tried the Dual band flower pot collinear ?

[GM4LLD]

@VK1DA

This effect is also found on the 3:1 ratio of the 40m and 15m band, the 40m antenna resonant on 7.1 is not also resonant on 21.3,

Yup, and fixed easily for a link dipole.

G4YSS: G/NP-015 & G/NP-006, 04-03-24

You’re lucky if your 40m dipole tunes well on 15m. There is an end effect capacitance on the dipole ends and the result of the capacitance is to lengthen the effective length. Or when you have trimmed for the antenna and measure it, it will be a bit shorter than you would expect, the end effect capacitance adds the missing length. When you go to 15m, 3x the frequency, the antenna is quite a bit too short as you have an antenna 3x the actual length. In my case my 40m dipole is well matched on 4…