New Transponder for us

On Dec 8, 1:03*pm, jcarlyle wrote:
For two reasons: *(1) it costs less to perform the biannual
inspection, and (2) you aren't broadcasting your tail number to the
Feds.

Ok, valid points.

I just checked with my local avionics shop. $95 for mode C and $125
for mode S. Not a deal breaker for me.

As to broadcasting the tail number - the TT21 installation menus
allow the aircraft ICAO code and the registration to be set but I
don't think there is an equipment requirement for them to be set. In
other words I think it will work if the defaults are left unchanged.
Is there any regulation that requires a mode S transponder to transmit
that data in US?

Andy

On Dec 8, 12:37*pm, Andy wrote:
On Dec 8, 1:03*pm, jcarlyle wrote:

For two reasons: *(1) it costs less to perform the biannual
inspection, and (2) you aren't broadcasting your tail number to the
Feds.

Ok, valid points.

I just checked with my local avionics shop. $95 for mode C and $125
for mode S. Not a deal breaker for me.

As to broadcasting the tail number *- the TT21 installation menus
allow the aircraft ICAO code and the registration to be set but I
don't think there is an equipment requirement for them to be set. *In
other words I think it will work if the defaults are left unchanged.
Is there any regulation that requires a mode S transponder to transmit
that data in US?

Andy

A Mode S transponder absolutely has to transmit the aircraft ICAO
address, a correctly configured ICAO address is required for the
transponder to actually work--bad things might happen if two aircraft
had the same default ICAO address were being interrogated at the same
time.

I am not sure where else this is captured in the regulations, but
checking this is a requirement at install and during the biannual
"Part 43 Appendix F" test.

Part 43 Appendix F...

(f) Mode S Address: Interrogate the Mode S transponder and verify that
it replies only to its assigned address. Use the correct address and
at least two incorrect addresses. The interrogations should be made at
a nominal rate of 50 interrogations per second.

---

I can't find it quickly in the regs but it may just be that the
requirement in 14CFR 91.215 (b) to operate in compliance with TSO
C-112 (which then captures you the pilot and not just the manufacturer
and that TSO's incorporation of RTCA DO-181 which may spell out the
Mode S address requirement). There better be an overriding
requirement, otherwise somebody could argue a pilot can can just
change it at any time. Yes its the off season but I'm not so bored yet
to fully follow this though.

Please be very careful here. Make sure your Mode S transponder is
using the correct ICAO address (the one registered to your aircraft).
If you really think you are goign to be doing bad things within view
of ATC then maybe you should rethink how you are flying.

Darryl

What Darryl said.

You might like to know that the avionics technician who did my VFR
transponder checks went to his computer and got the proper ICAO code
from the FAA. The reason is the "S" in Mode S stands for selective,
and they want to be darn sure ATC is broadcasting to the proper
aircraft.

I was being tongue in cheek with my previous post. There's no reason,
given the price and low power draw of the Trig TT21, that anyone
should even consider buying anything else right now (unless they're
replacing an existing transponder with the same type).

-John

On Dec 8, 3:37 pm, Andy wrote:
As to broadcasting the tail number - the TT21 installation menus
allow the aircraft ICAO code and the registration to be set but I
don't think there is an equipment requirement for them to be set. In
other words I think it will work if the defaults are left unchanged.
Is there any regulation that requires a mode S transponder to transmit
that data in US?

On Dec 8, 2:48*pm, jcarlyle wrote:
What Darryl said.

You might like to know that the avionics technician who did my VFR
transponder checks went to his computer and got the proper ICAO code
from the FAA. The reason is the "S" in Mode S stands for selective,
and they want to be darn sure ATC is broadcasting to the proper
aircraft.

All seems very reasonable and I would have no intention of using an
incorrect ICAO address. Did your technician also check that the
transmitted registration number, which seems to be a separate data
entry on the TT21, was correct?

Andy

Yes, he did.

-John

On Dec 8, 5:38 pm, Andy wrote:
All seems very reasonable and I would have no intention of using an
incorrect ICAO address. Did your technician also check that the
transmitted registration number, which seems to be a separate data
entry on the TT21, was correct?

Andy

On Dec 8, 1:48*pm, jcarlyle wrote:
What Darryl said.

You might like to know that the avionics technician who did my VFR
transponder checks went to his computer and got the proper ICAO code
from the FAA. The reason is the "S" in Mode S stands for selective,
and they want to be darn sure ATC is broadcasting to the proper
aircraft.

I was being tongue in cheek with my previous post. There's no reason,
given the price and low power draw of the Trig TT21, that anyone
should even consider buying anything else right now (unless they're
replacing an existing transponder with the same type).

-John

On Dec 8, 3:37 pm, Andy wrote:



As to broadcasting the tail number *- the TT21 installation menus
allow the aircraft ICAO code and the registration to be set but I
don't think there is an equipment requirement for them to be set. *In
other words I think it will work if the defaults are left unchanged.
Is there any regulation that requires a mode S transponder to transmit
that data in US?- Hide quoted text -

- Show quoted text -

Price is the reason $400 to $500 less than the Trig Mode C.

Richard
www.craggyaero.com

On Dec 9, 7:38*am, Richard wrote:
On Dec 8, 1:48*pm, jcarlyle wrote:



What Darryl said.

You might like to know that the avionics technician who did my VFR
transponder checks went to his computer and got the proper ICAO code
from the FAA. The reason is the "S" in Mode S stands for selective,
and they want to be darn sure ATC is broadcasting to the proper
aircraft.

I was being tongue in cheek with my previous post. There's no reason,
given the price and low power draw of the Trig TT21, that anyone
should even consider buying anything else right now (unless they're
replacing an existing transponder with the same type).

-John

On Dec 8, 3:37 pm, Andy wrote:

As to broadcasting the tail number *- the TT21 installation menus
allow the aircraft ICAO code and the registration to be set but I
don't think there is an equipment requirement for them to be set. *In
other words I think it will work if the defaults are left unchanged.
Is there any regulation that requires a mode S transponder to transmit
that data in US?- Hide quoted text -

- Show quoted text -

Price is the reason *$400 to $500 less than the Trig Mode C.

Richardwww.craggyaero.com

Trig does not make a "Mode C" transponder.

Darryl

On Dec 9, 7:46*am, Darryl Ramm wrote:
On Dec 9, 7:38*am, Richard wrote:





On Dec 8, 1:48*pm, jcarlyle wrote:

What Darryl said.

You might like to know that the avionics technician who did my VFR
transponder checks went to his computer and got the proper ICAO code
from the FAA. The reason is the "S" in Mode S stands for selective,
and they want to be darn sure ATC is broadcasting to the proper
aircraft.

I was being tongue in cheek with my previous post. There's no reason,
given the price and low power draw of the Trig TT21, that anyone
should even consider buying anything else right now (unless they're
replacing an existing transponder with the same type).

-John

On Dec 8, 3:37 pm, Andy wrote:

As to broadcasting the tail number *- the TT21 installation menus
allow the aircraft ICAO code and the registration to be set but I
don't think there is an equipment requirement for them to be set. *In
other words I think it will work if the defaults are left unchanged..
Is there any regulation that requires a mode S transponder to transmit
that data in US?- Hide quoted text -

- Show quoted text -

Price is the reason *$400 to $500 less than the Trig Mode C.

Richardwww.craggyaero.com

Trig does not make a "Mode C" transponder.

Darryl- Hide quoted text -

- Show quoted text -

Sorry I agree on the Mode S tell the other vendor to correct his web
site.

Trig TT21 Class 2 Mode C Transponder with Built-in Altitude Encoder
$2095

If you compare to the 35,000' $700 to $800 Less


Richard
www.craggyaero.com

On Dec 9, 8:58*am, Richard wrote:
Trig TT21 Class 2 Mode C Transponder with Built-in Altitude Encoder
$2095

If you compare to the 35,000' * * * $700 to $800 Less

Right, but you can buy the TT21 for a lot less than that if you shop
around. Trig has a minimum advertised retail price policy but some
vendors are selling much lower. It's the old "put one in the order
basket to see the real price" trick.

Check Aircraft Spruce as an example.

Andy

On Dec 9, 8:22*am, Andy wrote:
On Dec 9, 8:58*am, Richard wrote:

Trig TT21 Class 2 Mode C Transponder with Built-in Altitude Encoder
$2095

If you compare to the 35,000' * * * $700 to $800 Less

Right, but you can buy the TT21 for a lot less than that if you shop
around. *Trig has a minimum advertised retail price policy but some
vendors are selling much lower. *It's the old "put one in the order
basket to see the real price" trick.

Check Aircraft Spruce as an example.

Andy


Richard

You seem to be referring to this page http://www.cumulus-soaring.com/trig.htm
I expect Paul will have the "Mode C" typo fixed asap, but the same
page has lots of information on the Trig TT21/22 making clear they are
Mode S transponder.

---

There are at least three USA glider dealers actively selling the Trig
TT21.

Cumulus Soaring - http://www.cumulus-soaring.com/trig.htm
Williams Soaring - http://www.williamssoaring.com/catalog/index.html
(a dealer but no Trig info on their web store yet)
Wings and Wheels -
http://www.wingsandwheels.com/Transp...20Microair.htm

And Tim there is advertising this new Sandia transponder as well. Jeez
Tim! Maybe Tim or Richard can clarify the actual 12 VDC power
consumption of the Sandia transponder.

I understand the USA Trig distributor wanted higher upfront commitment
from the channel than other distributors and that may be a reason why
fewer dealers are carrying them than other brands. I don't know why
Craggy Aero does not sell the Trig transponders. It would seems a very
natural fit for the PowerFLARM that Craggy Aero has been doing a great
job promoting.

As for the relative cost. Most glider pilots do just fine installing a
lower cost and lower power consumption 125W transponder (whether a new
Trig TT21 or the Becker ATC-4401-175 many of us use). So for new
transponders for gliders in the USA any price comparison really should
be against the street price of a TT21. It really is irrelevant that
the Sandia is a 200W transponder, that does not justify a price
comparison to a Trig TT22 200W transponder. And as others have pointed
out we need to be a little careful comparing advertised and actual
street prices.

It is great to see pilots using a transponder (any transponder) where
we have high density airliner and fast jet traffic etc. and a Mode S
or Mode C transponder works well there today (but its the long term
ADS-B future where a Mode S shines). But I'd hate to see glider pilots
not aware of the issues and thinking that buying a cheaper Mode C
transponder today is a better decision than a slightly more expensive
Mode S transponder, especially when all the other important specs are
better with the Mode S. And I'd definitively not like to see us as a
community back in a situation where pilots are discussing debilitating
transponder power usage and more rounds of misinformation on power
consumption, and lack of use of transponders, because of this.

So Richard or Tim or anybody else do you have actual 12 VDC power
consumption specs on the Sandia transponder?

Darryl