Transponder: Mode-C or Mode-S?

On Sep 12, 11:55*pm, John Smith wrote:
Just be aware that the TT21 is a class 2 tansponder, i.e. not certified
for use above 15,000 feet, and therefore not suited for gliders. Buy the
TT22 instead which is class 1.

To date I've had 392 flights in gliders. I flew above 15,000 ft on a
flight on 17 Jan 1995 (in fact to 19,000 or so).

That's the ONLY time.

Most flights here don't go much above 5000 or 6000 ft. Even when
there's wave it's unusual to be able to get higher than maybe 12,000.

Your conditions are not the same as everyone's.

On Sep 12, 11:17*pm, Bruce Hoult wrote:
On Sep 12, 11:55*pm, John Smith wrote:

Just be aware that the TT21 is a class 2 tansponder, i.e. not certified
for use above 15,000 feet, and therefore not suited for gliders. Buy the
TT22 instead which is class 1.

To date I've had 392 flights in gliders. I flew above 15,000 ft on a
flight on 17 Jan 1995 (in fact to 19,000 or so).

That's the ONLY time.

Most flights here don't go much above 5000 or 6000 ft. Even when
there's wave it's unusual to be able to get higher than maybe 12,000.

Your conditions are not the same as everyone's.

I know what you mean. I had never gotten higher than 6K until I moved
to CA and started flying in the Sierras! Around here flying over 15K
is pretty routine. However, in my last glider I had a Becker 4401
which is also class 2 and I never had a problem. As a matter of fact
out of all the gliders in the Sierras, I would bet majority are using
class 2 transponders.


Cheers,
Morteza

On Sunday, September 11, 2011 at 11:54:26 PM UTC-4, Morteza Ansari wrote:
I recently bought a new bird and need to put a transponder in it. The
choice was obvious (until I took a closer look). Trig TT21 seems like
a great choice: small footprint, built-in encoder, 1090ES ADS-B out,
and descent price. However a bit more looking revealed more questions
than answers. It seems it requires an ISO GPS and one could not use
typical GPS sources we have in gliders, it is not clear if the ADS-B
out work with PowerFLARM (at least from what I have heard), and the
biannual testing cost 2-3x as much as mode-C.

Any thoughts/suggestions from more knowledgable folks?


Cheers,
Morteza

==============

Not sure how you got your conclusions or that gobbledygook you just uttered..
I have been using the TT-21 for over 10 years and it is flawless. It and the TT-22 are identical except for the transmit power. I have no GPS hooked to it or anything else. It runs like a normal txpndr. I hooked it up in one afternoon, and as mentioned has been working perfectly.

You're responding to an eight year old thread. There is plenty of recent discussion that is more relevant.

PA

On Tuesday, April 16, 2019 at 8:01:31 PM UTC-7, wrote:
On Sunday, September 11, 2011 at 11:54:26 PM UTC-4, Morteza Ansari wrote:
I recently bought a new bird and need to put a transponder in it. The
choice was obvious (until I took a closer look). Trig TT21 seems like
a great choice: small footprint, built-in encoder, 1090ES ADS-B out,
and descent price. However a bit more looking revealed more questions
than answers. It seems it requires an ISO GPS and one could not use
typical GPS sources we have in gliders, it is not clear if the ADS-B
out work with PowerFLARM (at least from what I have heard), and the
biannual testing cost 2-3x as much as mode-C.

Any thoughts/suggestions from more knowledgable folks?


Cheers,
Morteza

==============

Not sure how you got your conclusions or that gobbledygook you just uttered.
I have been using the TT-21 for over 10 years and it is flawless. It and the TT-22 are identical except for the transmit power. I have no GPS hooked to it or anything else. It runs like a normal txpndr. I hooked it up in one afternoon, and as mentioned has been working perfectly.

Welcome to r.a.s. This is an *excellent* first post.