On Saturday, November 30, 2019 at 7:30:25 PM UTC-8, Mike Schumann wrote:
On Saturday, November 30, 2019 at 8:26:42 AM UTC-6, Eric Greenwell wrote:
Darryl Ramm wrote on 11/29/2019 10:36 PM:
Again if you are installing TABS just set the transponder squat switch to "None" and use manual ON/ALT switching on the transponder.
I might forget to switch it correctly. Would using the "gear is down" switch to
change between ground/airborne be a sensible choice? The pattern (and the first
500'-1000' after the takeoff) would be flown showing the glider was on the ground,
of course, but that might be better than having the whole flight showing as on the
ground.
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
If you use a squat switch with a Trig transponder, I believe that also puts the Transponder into GRND mode, so it wouldn't be responding to interrogations. The one place you do want ADS-B OUT and your transponder operating is in the pattern. That's where half of the midairs occur. Turning off ADS-S B OUT or your transponder as soon as you lower the gear is a really bad idea.
Mike has an important point. Please do not dick around and end up disabling a safety system. If you are in the air the transponder needs to be in ALT mode.
What is actually going on is a bit more messy, but "not responding to interrogations" is a useful summary. In GND mode Mode-S transponders will actually reply to direct addressed Mode-S interrogations, and do some other things, but that a far from a necessary set for the transponder to operate normally (e.g. it can't be acquired as a target by SSR). It will keep transmitting ADS-B Out, but messages encode the glider is on the ground, and some message content changes slightly. How all different ADS-B receivers all respond to that is uh anybody's guess. I just have an image in my mind of somebody seeing a transponder reply LCD thingy blink when in GND mode at some time and say "ha see it's replying OK". Ah nope, it's replying to a small subset of stuff. Flying in GND mode is a bad idea.