Trig TT21 Transponder Thoughts?

[jcarlyle]

I need to replace a Terra TRT250D (it's failed for the 5th time). The
only transponder that might fit into the Terra's rectangular cutout in
my crowded panel (if I do some horizontal filling) is the Trig TT21.
The Trig's specifications look good and it has an attractive price,
but it's brand new on the market.

Does anyone have any experience or thoughts about the Trig TT21
transponder that they'd care to share?

-John

[Paul Remde]

Hi John,

Since you are located in the USA, you need to know that the Trig TT21 has
not been approved for use in the USA yet. It has recently received approval
for use in Europe, and it is supposedly in the approval process for the USA.
I look forward to selling them once they receive approval for use in the
USA. They may receive approval in 1 month, 6 months, 1 year, or possibly
never. I hope it will be very soon, but I have no idea.

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

"jcarlyle" > wrote in message
...
>I need to replace a Terra TRT250D (it's failed for the 5th time). The
> only transponder that might fit into the Terra's rectangular cutout in
> my crowded panel (if I do some horizontal filling) is the Trig TT21.
> The Trig's specifications look good and it has an attractive price,
> but it's brand new on the market.
>
> Does anyone have any experience or thoughts about the Trig TT21
> transponder that they'd care to share?
>
> -John

[Darryl Ramm]

On Jun 21, 7:14*am, jcarlyle > wrote:
> I need to replace a Terra TRT250D (it's failed for the 5th time). The
> only transponder that might fit into the Terra's rectangular cutout in
> my crowded panel (if I do some horizontal filling) is the Trig TT21.
> The Trig's specifications look good and it has an attractive price,
> but it's brand new on the market.
>
> Does anyone have any experience or thoughts about the Trig TT21
> transponder that they'd care to share?
>
> -John

I am not sure that the TT-21 has FAA TSO approval yet. I can see the
TT-31 in the TSO database (TSO-C112 2/29/2008) but not the TT-21. Is
anybody selling the TT-21 in the USA yet? I see claims on foreign
reseller websites for TSO approval for the T31 but I can't find that
claim on Trig's web site (they claim it will be approved) and I can't
find it in the FAA database, it would be great if it was approved.
Their (sole?) USA dealer is www.seaerospace.com and they only seem to
claim the TT31 is TSO approved.

I have no experience with any Trig transponder, but on paper at least
the Trig looks like a really nice device. I am also very curious to
hear from folks who have use it. It is compact, low power, should be
easy to mount with it's two box construction and with an built in
altitude encoder. It is Mode-S and supports ADS-B 1090ES out, which
gives you future compatibility to meet mandated ADS-B requirements.
What that means is that the Trig will support connecting a GPS data
source and broadcast the GPS location over ADS-B using the 1090ES
standard.

BTW some comments on ADS-B....

One thing to be aware of with that, and any 1090ES or UAT ADS-B device
in gliders, is that there is currently no low cost (IFR) certified GPS
unit that can be connected to provide the location data for ADS-B data
out. This problem is identical regardless of whether we are talking
about ADS-B over 1090ES or a UAT device. We've got 10 years or so to
solve that regulatory problem. Coverage is the second issue, there is
currently not good ADS-B coverage across the USA. The FAA has coverage
maps for for ADS-B roll out (both UAT and 1090ES).

That's the "1090ES" or "extended squitter" stuff or sometimes just
written as "ADS-B". The data transfer can be "in" or "out". A
transponder will support out, or both in and out. 1090ES out supports
sending the aircraft location and 1090ES in reads TIS-B traffic data
(or on a UAT also reads FIS-B weather and other data, a UAT can
support data services than 1090ES). And UATs based devices can support
data in or out or both. There are currently no UAT devices approved
for use that are suitable for gliders.


Not all Mode-S transponders have to provide ADS-B support. But I am
not aware of any curent Mode-S transponder sold in the USA that would
interest a glider pilot that does not at least have 1090ES out
capability. If there are any (compact, low power) glider compatible
Mode-S trasnponders that do *not* even do 1090ES out it would be great
to know.

The Trig transponders do not have 1090ES ADS-B out capability but not
1090ES in. Which means they cannot receive TIS-B traffic information
for display on a traffic display. Becker probably make the most
popular transponders in the USA for use in gliders. The current line
of Becker Mode-S claim to support ADS-B in and out but I am not aware
of anybody using this in a glider or any glider compatible traffic
display. It will be nice to see what happens if there is some pricing
competition for glider compatible Mode-S/1090ES transponders once the
Trig TT21 starts being sold in the USA.

The choice of a Mode-S 1090ES transponder gives you flexibility in
future for compatibility with ADS-B and is a much better choice for
traffic avoidance than UAT based ADS-B in traffic areas of mixed jets
and airliners since UAT devices provide *no* visibility to TCAS (and
there is no technical standard in which they can). TCAS is the last
critical part of the collision avoidance safety net and we really need
this when flying in regions of high density fast jet traffic. The FAA
and the industry really assumes that UATs are a supplement to existing
transponders, not a replacement. The nice thing about a Mode-S
transponder is it gives you options for the future, but with mandates
about a decade away a Mode-C transponder may still provide useful
economical life (and could be complemented with a UAT later, or be
replaced with a Mode-S 1090ES out transponder).

Hope that provides some useful information, even if it does not answer
the direct question.


Darryl

[jcarlyle]

Thanks very much, Darryl, for a thorough and very helpful reply. I
have a Mode C Becker in my ASW-19 and I've been very pleased with it,
but I can't fit a 57 mm transponder of any make into the LS8-18
without a major panel rebuild.

The key question for use in the USA is of course FAA TSO approval, and
as you say there isn't a clear answer to that question. I suspect Paul
Remde is correct that it hasn't yet gotten FAA approval, since SEA
says "now accepting TT21 orders" in a 5/28/2009 brochure, and more
importantly, you couldn't find it in the FAA database. However, SEA
does list TSO C112 and C88a approval on their TT21 catalog page! I'll
call SEA tomorrow and try to find out the true story with regard to
FAA TSO approval.

Meanwhile, is there anyone in Europe that has flight experience with
the Trig TT21?

-John

Darryl Ramm wrote:
> I am not sure that the TT-21 has FAA TSO approval yet. I can see the
> TT-31 in the TSO database (TSO-C112 2/29/2008) but not the TT-21. Is
> anybody selling the TT-21 in the USA yet? I see claims on foreign
> reseller websites for TSO approval for the T31 but I can't find that
> claim on Trig's web site (they claim it will be approved) and I can't
> find it in the FAA database, it would be great if it was approved.
> Their (sole?) USA dealer is www.seaerospace.com and they only seem to
> claim the TT31 is TSO approved.
>
> I have no experience with any Trig transponder, but on paper at least
> the Trig looks like a really nice device. I am also very curious to
> hear from folks who have use it. It is compact, low power, should be
> easy to mount with it's two box construction and with an built in
> altitude encoder. It is Mode-S and supports ADS-B 1090ES out, which
> gives you future compatibility to meet mandated ADS-B requirements.
> What that means is that the Trig will support connecting a GPS data
> source and broadcast the GPS location over ADS-B using the 1090ES
> standard.
>
> BTW some comments on ADS-B....
>
> One thing to be aware of with that, and any 1090ES or UAT ADS-B device
> in gliders, is that there is currently no low cost (IFR) certified GPS
> unit that can be connected to provide the location data for ADS-B data
> out. This problem is identical regardless of whether we are talking
> about ADS-B over 1090ES or a UAT device. We've got 10 years or so to
> solve that regulatory problem. Coverage is the second issue, there is
> currently not good ADS-B coverage across the USA. The FAA has coverage
> maps for for ADS-B roll out (both UAT and 1090ES).
>
> That's the "1090ES" or "extended squitter" stuff or sometimes just
> written as "ADS-B". The data transfer can be "in" or "out". A
> transponder will support out, or both in and out. 1090ES out supports
> sending the aircraft location and 1090ES in reads TIS-B traffic data
> (or on a UAT also reads FIS-B weather and other data, a UAT can
> support data services than 1090ES). And UATs based devices can support
> data in or out or both. There are currently no UAT devices approved
> for use that are suitable for gliders.
>
>
> Not all Mode-S transponders have to provide ADS-B support. But I am
> not aware of any curent Mode-S transponder sold in the USA that would
> interest a glider pilot that does not at least have 1090ES out
> capability. If there are any (compact, low power) glider compatible
> Mode-S trasnponders that do *not* even do 1090ES out it would be great
> to know.
>
> The Trig transponders do not have 1090ES ADS-B out capability but not
> 1090ES in. Which means they cannot receive TIS-B traffic information
> for display on a traffic display. Becker probably make the most
> popular transponders in the USA for use in gliders. The current line
> of Becker Mode-S claim to support ADS-B in and out but I am not aware
> of anybody using this in a glider or any glider compatible traffic
> display. It will be nice to see what happens if there is some pricing
> competition for glider compatible Mode-S/1090ES transponders once the
> Trig TT21 starts being sold in the USA.
>
> The choice of a Mode-S 1090ES transponder gives you flexibility in
> future for compatibility with ADS-B and is a much better choice for
> traffic avoidance than UAT based ADS-B in traffic areas of mixed jets
> and airliners since UAT devices provide *no* visibility to TCAS (and
> there is no technical standard in which they can). TCAS is the last
> critical part of the collision avoidance safety net and we really need
> this when flying in regions of high density fast jet traffic. The FAA
> and the industry really assumes that UATs are a supplement to existing
> transponders, not a replacement. The nice thing about a Mode-S
> transponder is it gives you options for the future, but with mandates
> about a decade away a Mode-C transponder may still provide useful
> economical life (and could be complemented with a UAT later, or be
> replaced with a Mode-S 1090ES out transponder).
>
> Hope that provides some useful information, even if it does not answer
> the direct question.
>
>
> Darryl

[Mike Schumann]

One note of caution about relying too much on TCAS for collision avoidance.
TCAS was designed as the last line of defense against collisions when all
else fails. It is NOT designed for use as the primary way to avoid
collisions. Unfortunately, given current FAA ATC procedures, this is the
way it is currently being used.

One of the problems with TCAS and gliders is that the TCAS logic is designed
for typical aircraft. As a result, TCAS is assuming that targets are
traveling in a relatively straight trajectory. Gliders don't do this, so
the TCAS RA may generate advice that actually creates a collision.

If you are really serious about minimizing the threat of collisions, you
also need a device that will show you where the other traffic is. If you
are in an area where there are ADS-B ground stations, an ADS-B UAT
transceiver is definitely the way to go. If you look at the FAA web site,
you will see that there currently is ground station coverage on the entire
east coast, in southern Florida, and in other isolated other areas of the
US. By next summer, there should be a major expansion of the ground station
coverage, with most of the US covered by 2011.

If you are not in an area with ADS-B coverage, a PCAS type of device is an
alternative.

Mike Schumann

"Darryl Ramm" > wrote in message
...
On Jun 21, 7:14 am, jcarlyle > wrote:
> I need to replace a Terra TRT250D (it's failed for the 5th time). The
> only transponder that might fit into the Terra's rectangular cutout in
> my crowded panel (if I do some horizontal filling) is the Trig TT21.
> The Trig's specifications look good and it has an attractive price,
> but it's brand new on the market.
>
> Does anyone have any experience or thoughts about the Trig TT21
> transponder that they'd care to share?
>
> -John

I am not sure that the TT-21 has FAA TSO approval yet. I can see the
TT-31 in the TSO database (TSO-C112 2/29/2008) but not the TT-21. Is
anybody selling the TT-21 in the USA yet? I see claims on foreign
reseller websites for TSO approval for the T31 but I can't find that
claim on Trig's web site (they claim it will be approved) and I can't
find it in the FAA database, it would be great if it was approved.
Their (sole?) USA dealer is www.seaerospace.com and they only seem to
claim the TT31 is TSO approved.

I have no experience with any Trig transponder, but on paper at least
the Trig looks like a really nice device. I am also very curious to
hear from folks who have use it. It is compact, low power, should be
easy to mount with it's two box construction and with an built in
altitude encoder. It is Mode-S and supports ADS-B 1090ES out, which
gives you future compatibility to meet mandated ADS-B requirements.
What that means is that the Trig will support connecting a GPS data
source and broadcast the GPS location over ADS-B using the 1090ES
standard.

BTW some comments on ADS-B....

One thing to be aware of with that, and any 1090ES or UAT ADS-B device
in gliders, is that there is currently no low cost (IFR) certified GPS
unit that can be connected to provide the location data for ADS-B data
out. This problem is identical regardless of whether we are talking
about ADS-B over 1090ES or a UAT device. We've got 10 years or so to
solve that regulatory problem. Coverage is the second issue, there is
currently not good ADS-B coverage across the USA. The FAA has coverage
maps for for ADS-B roll out (both UAT and 1090ES).

That's the "1090ES" or "extended squitter" stuff or sometimes just
written as "ADS-B". The data transfer can be "in" or "out". A
transponder will support out, or both in and out. 1090ES out supports
sending the aircraft location and 1090ES in reads TIS-B traffic data
(or on a UAT also reads FIS-B weather and other data, a UAT can
support data services than 1090ES). And UATs based devices can support
data in or out or both. There are currently no UAT devices approved
for use that are suitable for gliders.


Not all Mode-S transponders have to provide ADS-B support. But I am
not aware of any curent Mode-S transponder sold in the USA that would
interest a glider pilot that does not at least have 1090ES out
capability. If there are any (compact, low power) glider compatible
Mode-S trasnponders that do *not* even do 1090ES out it would be great
to know.

The Trig transponders do not have 1090ES ADS-B out capability but not
1090ES in. Which means they cannot receive TIS-B traffic information
for display on a traffic display. Becker probably make the most
popular transponders in the USA for use in gliders. The current line
of Becker Mode-S claim to support ADS-B in and out but I am not aware
of anybody using this in a glider or any glider compatible traffic
display. It will be nice to see what happens if there is some pricing
competition for glider compatible Mode-S/1090ES transponders once the
Trig TT21 starts being sold in the USA.

The choice of a Mode-S 1090ES transponder gives you flexibility in
future for compatibility with ADS-B and is a much better choice for
traffic avoidance than UAT based ADS-B in traffic areas of mixed jets
and airliners since UAT devices provide *no* visibility to TCAS (and
there is no technical standard in which they can). TCAS is the last
critical part of the collision avoidance safety net and we really need
this when flying in regions of high density fast jet traffic. The FAA
and the industry really assumes that UATs are a supplement to existing
transponders, not a replacement. The nice thing about a Mode-S
transponder is it gives you options for the future, but with mandates
about a decade away a Mode-C transponder may still provide useful
economical life (and could be complemented with a UAT later, or be
replaced with a Mode-S 1090ES out transponder).

Hope that provides some useful information, even if it does not answer
the direct question.


Darryl

[Darryl Ramm]

On Jun 21, 10:23*am, "Mike Schumann" <mike-nos...@traditions-
nospam.com> wrote:
> One note of caution about relying too much on TCAS for collision avoidance.
> TCAS was designed as the last line of defense against collisions when all
> else fails. *It is NOT designed for use as the primary way to avoid
> collisions. *Unfortunately, given current FAA ATC procedures, this is the
> way it is currently being used.
>
> One of the problems with TCAS and gliders is that the TCAS logic is designed
> for typical aircraft. *As a result, TCAS is assuming that targets are
> traveling in a relatively straight trajectory. *Gliders don't do this, so
> the TCAS RA may generate advice that actually creates a collision.
>
> If you are really serious about minimizing the threat of collisions, you
> also need a device that will show you where the other traffic is. *If you
> are in an area where there are ADS-B ground stations, an ADS-B UAT
> transceiver is definitely the way to go. *If you look at the FAA web site,
> you will see that there currently is ground station coverage on the entire
> east coast, in southern Florida, and in other isolated other areas of the
> US. *By next summer, there should be a major expansion of the ground station
> coverage, with most of the US covered by 2011.
>
> If you are not in an area with ADS-B coverage, a PCAS type of device is an
> alternative.
>
> Mike Schumann
>
[snip]


If all you want is TIS-B traffic information then a Mode-S transponder
can get you traffic data, provide TCAS compatibiiey, and also
compatibility with PCAS systems used in some gliders and GA aircraft.
I know Mike knows all this, that comment is to make it clear to
others.

TCAS is the absolute last defence and for high-traffic jet/airline
areas I just hope people will not think a glider would be better off
with ADS-B TIS-B traffic data *instead* of a transponder that provides
visibility to TCAS equipped jets.

While there are arguments about TCAS RA predictions, the RA are based
on altitude and jet traffic can climb or descend rapidly when needed
and the TCAS will monitor what is happening as the threat target
converge. This is not a satisfactory answer but I just worry that many
readers might thing that TCAS is doing some sophisticated track
avoidance and therefore a glider maneuvering might cause far more
complexity than the altitude based avoidance that actually happens.
Being primarily altitude based makes the resolution determination a
lot simpler. Gliders are also relatively slow moving, so even if
maneuvering their relative location to a fast jet does not move
rapidly. Gliders might change climb rates at +/- thousands of feet per
minute but with altitude margins in TCAS and the continuous monitoring
of altitude as targets converge probably make this less of an issue
than it could be. I am not aware of any technical study that shows
serious problems with gliders (or other slow traffic) and TCAS. I'd
love to see any if they exist.

With TCAS on TCAS targets the Mode-S transponders are communicating RA
data to ensure that both aircraft are not instructed to climb etc.
Since a glider won't have TCAS that won't happen, but the real issue
with that is avoiding TCAS directing both the jet aircraft with high
climb/descent performance to do the same thing, and the ultimate fall
back here is the ability of a jet to normally out-climb or out-descent
a glider even if the glider pilot decides to change altitude abruptly
to avoid a collision.

So again, the problem if people just relied on ADS-B UAT devices and a
TIS-B traffic display is that the glider would be entirely invisible
to TCAS. I would much rather have the TCAS help the fast jet avoid me
than me avoid the fast jet. But ideally have both. And ADS-B TIS-B
(either over UAT or 1090ES) offers more range than PCAS - one of the
issues with PCAS (I fly with a Zaon MRX) is it may not have sufficient
range to be useful for fast jet traffic. And even if you have a fancy
TIS-B display you may still decide to make an avoidance manouvre that
conflicts with what TCAS is telling the other aircraft to do. Again
this would rely on the jet typically being able to out climb or out
descend a glider.

Had the ASG-29 flying near Reno a few years ago had a simple
transponder the Hawker jet very likely would not have collided with
with it. ATC hopefully would have given the Hawker a traffic advisory
(but as Mike points out there is no guarantee that currently they
would have since both aircraft collided outside controlled airspace),
failing that the TCAS should have done its job. Likewise with another
incident near Reno more recently a transponder would likely have
avoided the jet pilots and ATC being "surprised" by a glider while on
approach to Reno, and the subsequent hassles for all involved.

BTW people wanting to see what TIS-B traffic on a UAT device might
look like in a real product -- the NavWorx PADS600 receives TIS-B (and
FIS-B) data, it does not do ADS-B out. See http://www.navworx.com. The
receiver is currently ~$1,500 and can display traffic data on a Garmin
496 or several other types of popular GA displays. As Mike points out,
this technology is quite interesting for the future.

Darryl

[Darryl Ramm]

On Jun 21, 11:28*am, Darryl Ramm > wrote:
> On Jun 21, 10:23*am, "Mike Schumann" <mike-nos...@traditions-
>
> nospam.com> wrote:
> > One note of caution about relying too much on TCAS for collision avoidance.
> > TCAS was designed as the last line of defense against collisions when all
> > else fails. *It is NOT designed for use as the primary way to avoid
> > collisions. *Unfortunately, given current FAA ATC procedures, this is the
> > way it is currently being used.
>
> > One of the problems with TCAS and gliders is that the TCAS logic is designed
> > for typical aircraft. *As a result, TCAS is assuming that targets are
> > traveling in a relatively straight trajectory. *Gliders don't do this, so
> > the TCAS RA may generate advice that actually creates a collision.
>
> > If you are really serious about minimizing the threat of collisions, you
> > also need a device that will show you where the other traffic is. *If you
> > are in an area where there are ADS-B ground stations, an ADS-B UAT
> > transceiver is definitely the way to go. *If you look at the FAA web site,
> > you will see that there currently is ground station coverage on the entire
> > east coast, in southern Florida, and in other isolated other areas of the
> > US. *By next summer, there should be a major expansion of the ground station
> > coverage, with most of the US covered by 2011.
>
> > If you are not in an area with ADS-B coverage, a PCAS type of device is an
> > alternative.
>
> > Mike Schumann
>
> [snip]
>
> If all you want is TIS-B traffic information then a Mode-S transponder
> can get you traffic data, provide TCAS compatibiiey, and also
> compatibility with PCAS systems used in some gliders and GA aircraft.
> I know Mike knows all this, that comment is to make it clear to
> others.
>
> TCAS is the absolute last defence and for high-traffic jet/airline
> areas I just hope people will not think a glider would be better off
> with ADS-B TIS-B traffic data *instead* of a transponder that provides
> visibility to TCAS equipped jets.
>
> While there are arguments about TCAS RA predictions, the RA are based
> on altitude and jet traffic can climb or descend rapidly when needed
> and the TCAS will monitor what is happening as the threat target
> converge. This is not a satisfactory answer but I just worry that many
> readers might thing that TCAS is doing some sophisticated track
> avoidance and therefore a glider maneuvering might cause far more
> complexity than the altitude based avoidance that actually happens.
> Being primarily altitude based makes the resolution determination a
> lot simpler. Gliders are also relatively slow moving, so even if
> maneuvering their relative location to a fast jet does not move
> rapidly. Gliders might change climb rates at +/- thousands of feet per
> minute but with altitude margins in TCAS and the continuous monitoring
> of altitude as targets converge probably make this less of an issue
> than it could be. I am not aware of any technical study that shows
> serious problems with gliders (or other slow traffic) and TCAS. I'd
> love to see any if they exist.
>
> With TCAS on TCAS targets the Mode-S transponders are communicating RA
> data to ensure that both aircraft are not instructed to climb etc.
> Since a glider won't have TCAS that won't happen, but the real issue
> with that is avoiding TCAS *directing both the jet aircraft with high
> climb/descent performance to do the same thing, and the ultimate fall
> back here is the ability of a jet to normally out-climb or out-descent
> a glider even if the glider pilot decides to change altitude abruptly
> to avoid a collision.
>
> So again, the problem if people just relied on ADS-B UAT devices and a
> TIS-B traffic display is that the glider would be entirely invisible
> to TCAS. I would much rather have the TCAS help the fast jet avoid me
> than me avoid the fast jet. But ideally have both. And ADS-B TIS-B
> (either over UAT or 1090ES) offers more range than PCAS - one of the
> issues with PCAS (I fly with a Zaon MRX) is it may not have sufficient
> range to be useful for fast jet traffic. And even if you have a fancy
> TIS-B display you may still decide to make an avoidance manouvre that
> conflicts with what TCAS is telling the other aircraft to do. Again
> this would rely on the jet typically being able to out climb or out
> descend a glider.
>
> Had the ASG-29 flying near Reno a few years ago had a simple
> transponder the Hawker jet very likely would not have collided with
> with it. ATC hopefully would have given the Hawker a traffic advisory
> (but as Mike points out there is no guarantee that currently they
> would have since both aircraft collided outside controlled airspace),
> failing that the TCAS should have done its job. Likewise with another
> incident near Reno more recently a transponder would likely have
> avoided the jet pilots and ATC being "surprised" by a glider while on
> approach to Reno, and the subsequent hassles for all involved.
>
> BTW people wanting to see what TIS-B traffic on a UAT device might
> look like in a real product -- the NavWorx PADS600 receives TIS-B (and
> FIS-B) data, it does not do ADS-B out. Seehttp://www.navworx.com. The
> receiver is currently ~$1,500 and can display traffic data on a Garmin
> 496 or several other types of popular GA displays. As Mike points out,
> this technology is quite interesting for the future.
>
> Darryl

Sorry my first para was supposed to say

If all you want is TIS-B traffic information then a Mode-S transponder
**with ADS-B in** can get you traffic data, provide TCAS
compatibility, and also compatibility with PCAS systems used in some
gliders and GA aircraft.

As mentioned in my first post in this thread the Becker Mode-S claim
to support ADS-B in for TIS-B. If I had a Becker Mode-S and lived near
ADS-B coverage I'd be playing with that now (done on the ground, a few
wires to a the transponder data out pins and see what is is sending
out...).

Darryl

[jcarlyle]

A question regarding ADS-B out capability on a Mode S transponder. Can
you feed the output of a glider GPS, say a Volkslogger, and into the
Mode S transponder?

Since the transponder and the encoder both require TSOs for use in the
USA airspace, I assume the answer to this question is an emphatic
"no".

A similar question for ADS-B in - are you required to display the TIS-
B and/or FIS-B data on a TSOed display?

-John

[Darryl Ramm]

On Jun 21, 1:10*pm, jcarlyle > wrote:
> A question regarding ADS-B out capability on a Mode S transponder. Can
> you feed the output of a glider GPS, say a Volkslogger, and into the
> Mode S transponder?
>
> Since the transponder and the encoder both require TSOs for use in the
> USA airspace, I assume the answer to this question is an emphatic
> "no".
>
> A similar question for ADS-B in *- are you required to display the TIS-
> B and/or FIS-B data on a TSOed display?
>
> -John

John

Correct. All ADS-B out requires an expensive certified GPS. That is an
issue for UAT and Mode-S/1090ES. There are people trying to change
this but it is a complex issue.

There is no requirement per-se to display the traffic on a TSO display
if the equipment is not permenently installed. IFR at the other
extreme is entirely another can of worms.

The Garmin 496 display for example that some vendors connect to just
use the legacy input defined for TIS-A on those devices. Most of that
TIS data should be easy to decode to display on PDA devices etc. We
will need soaring software vendors to support this. Since we don't
really want to be looking at the display we will also need those
vendors to impliment audible traffic alerts. That is not something
that a TIS-B receiver will normally do for you. Which is why I am
curious if somebody has got a Becker Mode-S hooked up in a glider to
do this.

BTW even ADS-B in only TIS-B receivers can have a GPS since they use
that to know where they are to output display data. Somewhere in the
reciever-display chain a GPS is needed.

Darryl

Darryl

[jcarlyle]

Thanks, Darryl - I'm much more educated now on ADS-B, TCAS, TIS-B and
FIS-B than I was this morning!

All I need now is input from anyone who has a Trig TT21, especially
with regard to ease of use and reliability.

-John

On Jun 21, 4:55 pm, Darryl Ramm > wrote:
> John
>
> Correct. All ADS-B out requires an expensive certified GPS. That is an
> issue for UAT and Mode-S/1090ES. There are people trying to change
> this but it is a complex issue.
>
> There is no requirement per-se to display the traffic on a TSO display
> if the equipment is not permenently installed. IFR at the other
> extreme is entirely another can of worms.
>
> The Garmin 496 display for example that some vendors connect to just
> use the legacy input defined for TIS-A on those devices. Most of that
> TIS data should be easy to decode to display on PDA devices etc. We
> will need soaring software vendors to support this. Since we don't
> really want to be looking at the display we will also need those
> vendors to impliment audible traffic alerts. That is not something
> that a TIS-B receiver will normally do for you. Which is why I am
> curious if somebody has got a Becker Mode-S hooked up in a glider to
> do this.
>
> BTW even ADS-B in only TIS-B receivers can have a GPS since they use
> that to know where they are to output display data. Somewhere in the
> reciever-display chain a GPS is needed.
>
> Darryl
>
> Darryl

[Peter Purdie[_4_]]

The TT21 has only just received its European approval, so there is very
little experience yet.

Playing with one on the bench, and making up a cable harness for an
installation, it looks good both for the installation and ease of use.
The documentation is clear, concise and comprehensive - a highly unusual
combination.

The two box solution means that the panel fit is easy, and the box that
does the real work can be positioned for a short co-ax run to the antenna
for minimum RF loss.

From my dealings with the company, I am impressed so far.

Peter

At 21:12 21 June 2009, jcarlyle wrote:
>Thanks, Darryl - I'm much more educated now on ADS-B, TCAS, TIS-B and
>FIS-B than I was this morning!
>
>All I need now is input from anyone who has a Trig TT21, especially
>with regard to ease of use and reliability.
>
>-John
>

[kd6veb]

The Zaon PCAS unit which is the size of a cigarette pack contains an
accurate pressure encoder plus almost all the electronics needed for a
transponder at a street price less than $500. What it does not have is
the high power transmitter. So I called the Zaon technical people and
suggested had they ever considered making an inexpensive, low power,
single unit tiny in size transponder. Their response was not seriously
because of the certification process but they would consider what I
suggested.
The bottom line to this is that the technology is available to make
a tiny inexpensive fully featured transponder and sell it for less
than a $1,000. Will it happen? Probably not. A couple more people from
the glider community talking to Zaon might be useful.
Zaon has almost the total market for PCAS deservedly because of
their 2 excellent products. They must be thinking of an encore.
How about a transponder?
Dave

PS There is not technical reason for a 2 piece transponder and the new
one discussed in this thread, in my opinion, still has not got it
right.

[Darryl Ramm]

On Jun 22, 7:32*am, kd6veb > wrote:
> * The Zaon PCAS unit which is the size of a cigarette pack contains an
> accurate pressure encoder plus almost all the electronics needed for a
> transponder at a street price less than $500. What it does not have is
> the high power transmitter. So I called the Zaon technical people and
> suggested had they ever considered making an inexpensive, low power,
> single unit tiny in size transponder. Their response was not seriously
> because of the certification process but they would consider what I
> suggested.
> * The bottom line to this is that the technology is available to make
> a tiny inexpensive fully featured transponder and sell it for less
> than a $1,000. Will it happen? Probably not. A couple more people from
> the glider community talking to Zaon might be useful.
> * Zaon has almost the total market for PCAS deservedly because of
> their 2 excellent products. They must be thinking of an encore.
> How about a transponder?
> Dave
>
> PS There is not technical reason for a 2 piece transponder and the new
> one discussed in this thread, in my opinion, still has not got it
> right.

I'll bite.

There are RF engineering reasons why it will be harder to put a PCAS
and Transponder in the same box. Zaon would an uphill battle already
enterign the transponder market for light aircraft with Becker and
others and now Trig with some pretty nice transponders. Zaon does low-
end traffic avoidance, they need to be focused on keeping there
leadership there. with ADS-B (Both UAT and 1090ES) is the future of
traffic avoidance in the GA fleet and that is where Zaon should be
spending there time. I'd hope they are working on a combined PCAS+UAT
(data in only) device. Otherwise devices like the NavWorx PADS600 will
take that market away from Zaon as ADS-B starts being adopted.

There are often great reasons for a two box transponder. Including
being able to mount the RF box nearer the antenna and simplify cabling
and save RF power loss as the previous owner mentioned. However with
the need to plumb the transponder to a static line there may be
tradeoffs between static line and coaxial cable routing. You also get
to avoid RF coax cable flex and damage with gliders with front hinged
panels. The compact control head allows mounting in shallow panels,
takes weight off the panel mount screws etc.

The Trig TT21 RF box is also significantly smaller than other two box
or single box transponders. e.g. the TT21 RF box is 5.6" x 2.4" x
1.8". A normal Becker Mode-S panel mount is 8.0" x 2.4" x 2.4" and a
remote mount box is 8.5" x 2.4" x 2.4". That makes it easier to mount
in many remote locations.

The only nits I have to pick withe TT21 is it does not appear to allow
tandem installation (dual control heads), and as mentioned easier it
supports ADS-B 1090ES out but not in. But (I forgot to mention this
earlier) there is a tantalizing RS-232 port for "future upgrades". Mmm
I wonder if that could be for ADS-B TIS-B out. Either way, given its
price and size and other things if it works as claimed and is reliable
it looks to me like a winner.

Darryl

[Peter Purdie[_3_]]

The pressure transducer in the TRIG is in the panel control unit -Trig
thought of that one.

The certification issue is a big one, because the bureaucracies that do
the specifying want to tie everything dowm to a tight spec., but only
consider what they have thought of. Intelligent solutions are not welcome
- it implies they didn't think.


>There are often great reasons for a two box transponder. Including
>being able to mount the RF box nearer the antenna and simplify cabling
>and save RF power loss as the previous owner mentioned. However with
>the need to plumb the transponder to a static line there may be
>tradeoffs between static line and coaxial cable routing. You also get
>to avoid RF coax cable flex and damage with gliders with front hinged
>panels. The compact control head allows mounting in shallow panels,
>takes weight off the panel mount screws etc.
>

[jcarlyle]

I received an answer directly from Trig today in response to an e-mail
that I sent yesterday.

Trig says that the TT21 "is not yet legal for use in FAA approved
aircraft". Trig is actively working on FAA TSO approval (they already
have European TSO certification), but they say that any date they
might give for FAA approval "would be nothing more than a very very
rough estimate". As for SEA stating C112 and C88a certification, Trig
says that that is a mistake and that they will contact SEA about it.
They feel that SEA wrote that in anticipation that they "will have a
TSO sooner or later".

Trig also says that if I "can wait several months it [will] certainly
[be] worth the wait". I think I'll be doing just that...

-John

On Jun 21, 12:54 pm, jcarlyle > wrote:
> The key question for use in the USA is of course FAA TSO approval, and
> as you say there isn't a clear answer to that question. I suspect Paul
> Remde is correct that it hasn't yet gotten FAA approval, since SEA
> says "now accepting TT21 orders" in a 5/28/2009 brochure, and more
> importantly, you couldn't find it in the FAA database. However, SEA
> does list TSO C112 and C88a approval on their TT21 catalog page! I'll
> call SEA tomorrow and try to find out the true story with regard to
> FAA TSO approval.

[Free Flight 107]

On Jun 21, 8:54*am, "Paul Remde" > wrote:
> Hi John,
>
> Since you are located in the USA, you need to know that the Trig TT21 has
> not been approved for use in the USA yet. *It has recently received approval
> for use in Europe, and it is supposedly in the approval process for the USA.
> I look forward to selling them once they receive approval for use in the
> USA. *They may receive approval in 1 month, 6 months, 1 year, or possibly
> never. *I hope *it will be very soon, but I have no idea.
>
> Best Regards,
>
> Paul Remde
> Cumulus Soaring, Inc.
>
> "jcarlyle" > wrote in message
>
> ...
>
>
>
> >I need to replace a Terra TRT250D (it's failed for the 5th time). The
> > only transponder that might fit into the Terra's rectangular cutout in
> > my crowded panel (if I do some horizontal filling) is the Trig TT21.
> > The Trig's specifications look good and it has an attractive price,
> > but it's brand new on the market.
>
> > Does anyone have any experience or thoughts about the Trig TT21
> > transponder that they'd care to share?
>
> > -John- Hide quoted text -
>
> - Show quoted text -

I'm in the same boat as John, are there any other choices for the
replacement of the Terra 250D? Or doesanyone have one for sale?

I already have the hole and slide chassis in place and it died just
last week. My little Libelle and I miss it already.

Wayne at Walker dot org

[Mike Schumann]

You need to be VERY careful about investing in the PADS600 UAT receiver.
The ITT ADS-B ground stations that are currently being deployed nationwide
will only transmit traffic and weather data in response to receiving an
ADS-B out interrogation from an ADS-B UAT equipped aircraft. They do not
transmit this data continuously. As a result, the PADS600 will only receive
this data when it is listening in on data being sent to other aircraft.

If you want reliable traffic and weather data via ADS-B, you need to invest
in an ADS-B transceiver that supports both ADS-B In and Out functionality.

Mike Schumann

"Darryl Ramm" > wrote in message
...
On Jun 21, 10:23 am, "Mike Schumann" <mike-nos...@traditions-
nospam.com> wrote:
> One note of caution about relying too much on TCAS for collision
> avoidance.
> TCAS was designed as the last line of defense against collisions when all
> else fails. It is NOT designed for use as the primary way to avoid
> collisions. Unfortunately, given current FAA ATC procedures, this is the
> way it is currently being used.
>
> One of the problems with TCAS and gliders is that the TCAS logic is
> designed
> for typical aircraft. As a result, TCAS is assuming that targets are
> traveling in a relatively straight trajectory. Gliders don't do this, so
> the TCAS RA may generate advice that actually creates a collision.
>
> If you are really serious about minimizing the threat of collisions, you
> also need a device that will show you where the other traffic is. If you
> are in an area where there are ADS-B ground stations, an ADS-B UAT
> transceiver is definitely the way to go. If you look at the FAA web site,
> you will see that there currently is ground station coverage on the entire
> east coast, in southern Florida, and in other isolated other areas of the
> US. By next summer, there should be a major expansion of the ground
> station
> coverage, with most of the US covered by 2011.
>
> If you are not in an area with ADS-B coverage, a PCAS type of device is an
> alternative.
>
> Mike Schumann
>
[snip]


If all you want is TIS-B traffic information then a Mode-S transponder
can get you traffic data, provide TCAS compatibiiey, and also
compatibility with PCAS systems used in some gliders and GA aircraft.
I know Mike knows all this, that comment is to make it clear to
others.

TCAS is the absolute last defence and for high-traffic jet/airline
areas I just hope people will not think a glider would be better off
with ADS-B TIS-B traffic data *instead* of a transponder that provides
visibility to TCAS equipped jets.

While there are arguments about TCAS RA predictions, the RA are based
on altitude and jet traffic can climb or descend rapidly when needed
and the TCAS will monitor what is happening as the threat target
converge. This is not a satisfactory answer but I just worry that many
readers might thing that TCAS is doing some sophisticated track
avoidance and therefore a glider maneuvering might cause far more
complexity than the altitude based avoidance that actually happens.
Being primarily altitude based makes the resolution determination a
lot simpler. Gliders are also relatively slow moving, so even if
maneuvering their relative location to a fast jet does not move
rapidly. Gliders might change climb rates at +/- thousands of feet per
minute but with altitude margins in TCAS and the continuous monitoring
of altitude as targets converge probably make this less of an issue
than it could be. I am not aware of any technical study that shows
serious problems with gliders (or other slow traffic) and TCAS. I'd
love to see any if they exist.

With TCAS on TCAS targets the Mode-S transponders are communicating RA
data to ensure that both aircraft are not instructed to climb etc.
Since a glider won't have TCAS that won't happen, but the real issue
with that is avoiding TCAS directing both the jet aircraft with high
climb/descent performance to do the same thing, and the ultimate fall
back here is the ability of a jet to normally out-climb or out-descent
a glider even if the glider pilot decides to change altitude abruptly
to avoid a collision.

So again, the problem if people just relied on ADS-B UAT devices and a
TIS-B traffic display is that the glider would be entirely invisible
to TCAS. I would much rather have the TCAS help the fast jet avoid me
than me avoid the fast jet. But ideally have both. And ADS-B TIS-B
(either over UAT or 1090ES) offers more range than PCAS - one of the
issues with PCAS (I fly with a Zaon MRX) is it may not have sufficient
range to be useful for fast jet traffic. And even if you have a fancy
TIS-B display you may still decide to make an avoidance manouvre that
conflicts with what TCAS is telling the other aircraft to do. Again
this would rely on the jet typically being able to out climb or out
descend a glider.

Had the ASG-29 flying near Reno a few years ago had a simple
transponder the Hawker jet very likely would not have collided with
with it. ATC hopefully would have given the Hawker a traffic advisory
(but as Mike points out there is no guarantee that currently they
would have since both aircraft collided outside controlled airspace),
failing that the TCAS should have done its job. Likewise with another
incident near Reno more recently a transponder would likely have
avoided the jet pilots and ATC being "surprised" by a glider while on
approach to Reno, and the subsequent hassles for all involved.

BTW people wanting to see what TIS-B traffic on a UAT device might
look like in a real product -- the NavWorx PADS600 receives TIS-B (and
FIS-B) data, it does not do ADS-B out. See http://www.navworx.com. The
receiver is currently ~$1,500 and can display traffic data on a Garmin
496 or several other types of popular GA displays. As Mike points out,
this technology is quite interesting for the future.

Darryl