Trig TT21 transponder draws only 125 mA!

On Mar 15, 12:53*pm, hans wrote:
I fly now for 2 years with a Garrecht ultra compact transponder, and the
addition of the transponder, which always on ALT in the air has not
significantly changed the number of hours I get out of my batteries. The
hx4700 draws much more than the transponder.

Am 15.03.2010 04:37, schrieb Steve Koerner:

I know that a number of folks have been waiting for hard data on the
current consumption of the new Trig transponder in actual operating
conditions.

I measured the current consumption today on an actual flight of 2
hours 52 minutes. * The flight was in fairly congested airspace all
within 10 miles of Turf Soaring school which is located just outside
the Phoenix Class B airspace. * In fact, some of the flight was under
the class B shelf. * The transponder was continuously on in ALT mode.
I noted that it was being interogated at irregular intervals that
averaged about once every one or two seconds.

I have two batteries on board. *For the test, one battery was powering
only the transponder. *I had an Astro Flights watt meter connected to
the battery which functions to integrate the current consumption and
reports actual Ampere Hours of battery draw. * Total draw for the
flight was measured as .353 AH which calculates to 125 mA average over
the duration of the flight.

Here's a reference to the Astro Flights watt meter for those that
might be interested:
http://www.astroflight.com/index.php...=index&cPath=2

I'm an EE and I have independently verified the accuracy of my watt
meter against a precision lab instrument.

Steve Koerner
www.wingrigger.com

Yes, don't leave out the PDA/PNA, in my glider an HP310 consumes about
the same if not more than a Microair Transponder.

Brian