I would be a bit worried about the xponder antenna frying my brain - thus I
like it under my bum with a circular 5 1/2 inch circular ground plain (if
glass glider) so nothing gets into my body except the bottom part of my
legs and they do not matter. Xponders put out a lot of power!!
That all
Ian McPhee (skype macca304)
Box 657
Byron Bay NSW 2481 Australia
Tel +61(0)2 66847642 mob +61(0)428847642
ianmcphee AT aapt.net.au
ww.mrsoaring.com


"Tim Mara" wrote in message
...
what many keep failing to realize is that the Transponder is there so YOU
can be seen.......and so that ATC can see you and other traffic to try to
redirect them (VFR Traffic on a work load permitting basis!!) and provide
separation.....Transponders I am afraid can do more to relax the pilot
into an unsafe feeling of security that "big brother" is looking out for
you....this certainly is not the case....Though a transponder may offer
you some additional safety, you have to realize that unless you are in
contact with ATC there is no way for them to notify YOU that there is
traffic as well....not everyone will have a TCAS system (few Cezna 150's
do that I know of) and not every corporate or airliner is going to move to
avoid you, especially if ATC doesn't see you clearly and notify them that
you are "somewhere" up there also... If you fly where there is a
possibility of airliners you should then monitor the ATC frequency and
even notify them that you are there and on the frequency..they too will
want to see you on their screen as well.
Tim
Wings & Wheels
www.wingsandwheels.com

"Andy" wrote in message
oups.com...

Tim Mara wrote:

Also I note that you say you have a transponder antenna mounted
vertically
on the top of the fuselage.........this is also not a proper
installation
since transponder antennas are intended to be directed toward the ground
(radar receivers) and Carbon fuselages will block or even absorb signals
rather than reflect them away as a proper ground plane does.


If there is a choice of being seen either from above, or from below,
I'll take above every time. I'd far rather be seen on the TCAS of an
airliner that is descending through cloud into me than be seen on a
controller's screen.

Has anyone actually measured the antenna patterns for top or bottom
mounted transponder antennas on a typical carbon glider? Is the
masking a real problem?


Andy