On Mon, 30 Nov 2015 21:14:47 +0000, Brian Reay wrote:

I've used a tapped coil and switch caps as well (also remotely) but the
motorised system gave better control and, once tuned, didn't require power.

Not exactly. The relays in most ATU's are magnetically latched and
will maintain their state when power is removed. That's how they get
low power operation.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558