Transponder: Mode-C or Mode-S?

On 9/13/2011 9:27 AM, kd6veb wrote:
Hi Gang
I had a Trig mode S transponder installed in my new Phoenix motor
glider. It appears to work fine as a mode C transponder. After
questioning NorCal while soaring they confirmed they could detect it
with their sqwark code, it would IDENT and so on - all the mode C
stuff. However most of the US including northern California/Nevada is
not yet set up for mode S so except for the future there is no reason
to have mode S in the US. Of course there are other reasons to have
mode S, probably the most important would be if you wanted to sell a
glider in Europe where mode S is becoming mandatory. For that market
having a mode S transponder will save the buyer about $2,500 - the
cost of replacing a mode C with a mode S transponder.
Dave

A Trig Mode S unit is same cost as the comparable Becker when you add in
the cost of the encoder and harness the Becker requires, so there isn't
any financial reason to buy a Mode C transponder. The Trig has a much
lower current drain, making it the preferred choice anyway.

If you already have a Mode C, there probably isn't any reason to upgrade
now.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl