<x-flowed>
          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
          <<  Lancair Builders' Mail List  >>
          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
>>
We've been chasing a similar problem with the electromechanical fuel gauges
in a newly completed Glasair-II S RG. Whenever the PTT switch activates the
transmitter(s), both fuel gauges (main & header) jump nearly to the peg.
There are capacitance type sender units in each tank, and as part of our
investigation, I keyed my handheld AC-22 in the cockpit and got exactly the
same reaction.

Clearly the fuel gauge wiring is acting as an antenna in this builder's
installation, and we initially have wound some of each gauge's wiring around
a magnetic choke. This has dramatically reduced the effect, but not
eliminated it. We are going to try adding a small capacitor across each of
the probe/sender unit leads next. Shielded wiring is a third option.

Haven't noticed yet if the effect extends to any of the indicators on the
VMI LCD. Will have to watch for this.

Best Regards,

Larry Graves
AirCrafters Builder Assistance Center
140 Aviation Way, Watsonville, CA 95076
Tel 831-722-9141 Fax 831-722-9142
www.AirCraftersLLC.com

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
LML website:   http://www.olsusa.com/Users/Mkaye/maillist.html
LML Builders' Bookstore:   http://www.buildersbooks.com/lancair

Please send your photos and drawings to marvkaye@olsusa.com.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
</x-flowed>