Topband: Trees And RF - Suggested Test

[Ward Silver]

I suggest the following tests to be done by someone else than me...any of which could give us some anecdotal evidence about trees and RF, at least.

Wind a several-turn solenoidal coil with a diameter large enough for a section of tree to be inserted. Measure the inductance and the Q with and without the branch inserted.  Significant changes in the L or Q (at RF) would indicate interaction between tree and field.

Make a vertical dipole and suspend the top from a pulley that can move along a non-conductive catenary (i.e. - a rope) between two trees at least one-half wavelength apart.  Measure the resonant frequency and SWR bandwidth of the dipole when suspended in the middle of the catenary.  Move the dipole closer to the tree in steps of about 0.1 wavelength, repeating the resonant frequency and SWR bandwidth measurements at each step.  Significant shifts in either resonant frequency or increases in the SWR bandwidth indicate interaction between tree and field.

Have at it - that would make a nice QST or QEX article!

73, Ward N0AX