John wrote:
Do the 2m 9 element Tonnas have insulated reflectors/directors or are they
electrically grounded to the boom?

Tonna's production over the last several years uses insulated plastic
clips on top of the boom. These came in at about the same time as the
sleeve "balun" for the driven element.

If you're offered an old one that uses elements through the boom with
metal clips, you should probably just say no. At its present age the
boom-element contacts will be corroded and unreliable.

With all old Tonnas, there's also a question about corrosion of the
riveted joint between the driven element and the hairpin loop, inside
the insulator where you can't get to clean it. I've used Tonnas for many
years, but on new driven elements I now apply hot-melt glue around the
locations where water could get in.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek