Which towers for testing radio equipment (not regular transmission towers) do you know?
I know the two metal-free wood towers of the antenna test facility in Brück, Germany

http://en.structurae.de/files/photos/1803/br2.jpg
Messturm II, Brück, Germany ( http://en.structurae.de/structures/data/index.cfm?ID=s0010788 )

http://en.structurae.de/files/photos/1803/br3.jpg
Messturm III, Brück, Germany ( http://en.structurae.de/structures/data/index.cfm?ID=s0010787 )

Note: both towers do not permanently carry antennas! The wire inside the tower is the lightning conductor and it can be demounted in a short time.

Another tower of this category was Tesla's Wardenclyffe Tower

http://upload.wikimedia.org/wikipedia/en/f/ff/BrochureWardenclyffe_.PNG
Wardenclyffe Tower, Shoreham, USA ( http://en.wikipedia.org/wiki/Wardenclyffe_Tower )