Mark what kind of antennas are you using? If tape was the coax
           connected in the center. I assume they and the coax are
   bonded in
           so there is little you can do about changing anything having
   to do
           with that.

           The other thing I am curious about is the new box that converts
           the fuel sensor value to a variable frequency pulse. Please look
       inside
           and tell me the numbers on the chips if they are readable of
   course.
           Some manufacturers mask the numbers sometimes so it makes it
           more difficult to copy the circuit.

           The diodes Aubrey mentions may be embedded in the chip or
   chips what
           ever the case may be. In that case the only thing I think
   you can
           do is put them in a shielded box and move it away from the coax.

           --
           Paul Lamar ...No rotor no motor.


       Paul (and others),
       I made a breakthrough this  weekend on the fuel probe problem.  I
       rewired the right probe with shielded wire from the probe all
   the way to
       the EFIS.  Power up the EFIS and Nav/Com, hit PTT, and the gauge is
       steady as a rock.  The left gauge (the one that I haven't
   changed) still
       acted up as always, but it will be next to fix.  But the right
   one with
       shielded wire appears to be working great.  It was too late in
   the day
       to fly it, but I feel 99% certain that this has corrected the
   problem.

       Thanks to everyone that shared their ideas and suggestions on
   how to fix
       this very annoying (and potentially dangerous) problem.

       Mark S.
       25.5 hrs

       Congratulations Mark. You had a real bear of a problem there for
   awhile.
       These kinds of problems usually require real expensive instruments
       to trouble shoot like field strength meters and VSWR meters.

       Probably a good plan of attack is shield everything in an airplane
       including all the engine computer wiring.
       --
       Paul Lamar ...No rotor no motor.


   Shielding power and (especially) ground will rarely provide value in
   most systems - especially those that burn any significant amount of
   power - RF noise like this is low energy only affecting low power
   devices like sensors..  There would be _no_ value in shielding any dc
   lighting circuit wiring (nav/landing, cabin, panel lights), and likely
   no value in shielding the power leads to radios or other avionics.

   Shielding low voltage signaling wires (sensors) where appropriate can be
   a good deal.

   Thanks to Mark for letting us know what the resolution was.


   Regards,

   Matt-

   That assumes people know what is what :) Electricity is a mystery to
   most:)

   Paul Lamar


Paul,
I'm using a Bob Archer antenna.  It is bonded onto one inner skin of the
vertical tail.  I have a picture somewhere, but it may take a while to
find it.  I had a friend check it with a VSWR meter prior to assembling
the tail and it tested very good, but don't remember the numbers.

Mark
25.5 hrs

Thanks Mark.

BTW Mark we need some more pictures of rotary powered aircraft for Youtube taking
off and landing. If you or Tom have a friend with a video camera with a telephoto
lens mounted on a tripod that would work best. Please set it up about half way
down the runway looking back at the start. A lot of YouTube vidios are junk
because they use hand held cameras. Al Gietzen has a great video but for some
reason it is not on Youtube yet.

http://www.rotaryeng.net/Velocity_Vignette.wmv

BTW It does not appear to be widely recognized yet but Youtube is a great
way to advertise. If you spend a million dollars on a one minute ad on TV it is
seen only once. If you put it on Youtube for free it will be seen for the next five
years. I think Youtube viewing is also doubling every year. Pretty soon half
the people will use it for entertainment instead of TV as you don't have
to look at unrelated commercials.