New small transponder

Darryl Ramm wrote:
The TT21 is a class 2 transponder and therefore *not* suited for
gliders. If you choose to go with Trig, then do yourself a favour and
buy the TT22.

The TT21 is very suitable for gliders. Its being installed in many
gliders in the USA and I expect elsewhere. The issue between class 1
and 2 transponders comes down to a fairly meaningless difference in
output power when you compare 15,000' vs. the maximum altitude we
typically fly at.

If you ever want to climb above 15,000 ft in an airspace where a
tansponder is mandatory (which I do regularly), then you are just plain
illegal with the TT21. This may be "fairly meaningless" for you, it's
not for me and should not be for any pilot.

On Mar 3, 7:19*pm, Eric Greenwell wrote:
On 3/3/2011 5:28 PM, Dave White wrote:

This is the article from the EAA newsletter:

http://www.ksallink.com/?cmd=display...13&format=html

This is the manufacturer:

http://www.aaicorp.com

Wonder if they might consider adapting this thing to gliders?

Pro: the "power box" is about half the thickness of a Trig power box.

Cons: The power consumption is greater than a Trig according to their
data sheet, it's not TSO'd.

It would have to be several hundred dollars cheaper the Trig than to
appeal to me enough to dump my Becker, based on those pros/cons.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

Unlike the Trig TT21/TT22 the encoder is not built into the control
head, its a separate box that appears to be be bolted onto the RF
unit, its not clear if the same encoder can be used separately
connected via a cable or if third party encoders are supported. The
Trig scheme is really nice for gliders since you just run one control
cable from the panel area to wherever the RF box is mounted (hopefully
close to the antenna).

Sage is obviously a small company, their product data sheets seem to
show hand made prototypes and although things like "FAA TSO" show on
them but nothing from Sage is FAA/TSO approved. The January 2011 data
sheet says "We are accepting orders for non-
TSO certified Mode C transponders now." The difference in complexity
between a Mode C and Mode S transponder is enormous, so it would be
interesting to know the actual state of their Mode S product
development. Anybody know where their Mode S development is at?

The RF unit looks impressively small but I would have concerns about
the use of a surface mount SMA connector vs. the standard panel mount
TNC coax connector and how fragile this will be in practice, specially
if connected to a larger adapter. But a fine tradeoff for a small UAV
installation done at a UAV manufacturer.

Darryl

On Mar 4, 11:56*am, Darryl Ramm wrote:
On Mar 3, 7:19*pm, Eric Greenwell wrote:



On 3/3/2011 5:28 PM, Dave White wrote:

This is the article from the EAA newsletter:

http://www.ksallink.com/?cmd=display...13&format=html

This is the manufacturer:

http://www.aaicorp.com

Wonder if they might consider adapting this thing to gliders?

Pro: the "power box" is about half the thickness of a Trig power box.

Cons: The power consumption is greater than a Trig according to their
data sheet, it's not TSO'd.

It would have to be several hundred dollars cheaper the Trig than to
appeal to me enough to dump my Becker, based on those pros/cons.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

Unlike the Trig TT21/TT22 the encoder is not built into the control
head, its a separate box that appears to be be bolted onto the RF
unit, its not clear if the same encoder can be used separately
connected via a cable or if third party encoders are supported. The
Trig scheme is really nice for gliders since you just run one control
cable from the panel area to wherever the RF box is mounted (hopefully
close to the antenna).

Sage is obviously a small company, their product data sheets seem to
show hand made prototypes and although things like "FAA TSO" show on
them but nothing from Sage is FAA/TSO approved. The January 2011 data
sheet says "We are accepting orders for non-
TSO certified Mode C transponders now." The difference in complexity
between a Mode C and Mode S transponder is enormous, so it would be
interesting to know the actual state of their Mode S product
development. Anybody know where their Mode S development is at?

The RF unit looks impressively small but I would have concerns about
the use of a surface mount SMA connector vs. the standard panel mount
TNC coax connector and how fragile this will be in practice, specially
if connected to a larger adapter. But a fine tradeoff for a small UAV
installation done at a UAV manufacturer.

Darryl

Also the list price on the Mode S transponder (which as mentioned is
not yet apparently available even for pre-order) is shown on their
price list as $3,587 which does not seem to be too competitive
compared to the current street price of ~$2,200 for the Trig TT21. Of
course comparing a future list price vs. current street price may not
be that useful. And $3,587 not say $3,600, curious price specificity
there.

Darryl

At 12:49 04 March 2011, John Smith wrote:
Am 04.03.11 13:01, schrieb Nigel Cottrell:
This looks a lot like the Trig 21 which I have had fitted in a
powered
plane for about 18 months and am very happy with.

http://www.trig-avionics.com/library/TT2xBrochure.pdf

The TT21 is a class 2 transponder and therefore *not* suited for
gliders. If you choose to go with Trig, then do yourself a favour
and
buy the TT22.
If you want a Class 1 the best option currently available is probably
the TT22.
Here in the UK the possibility of flight above 10000' is very limited
Wales, Scotland and a few areas in the North of England and so
wouldn't be a consideration for the vast majority of owners.

On 3/4/2011 11:44 AM, John Smith wrote:
Darryl Ramm wrote:
The TT21 is a class 2 transponder and therefore *not* suited for
gliders. If you choose to go with Trig, then do yourself a favour and
buy the TT22.

The TT21 is very suitable for gliders. Its being installed in many
gliders in the USA and I expect elsewhere. The issue between class 1
and 2 transponders comes down to a fairly meaningless difference in
output power when you compare 15,000' vs. the maximum altitude we
typically fly at.

If you ever want to climb above 15,000 ft in an airspace where a
tansponder is mandatory (which I do regularly), then you are just plain
illegal with the TT21. This may be "fairly meaningless" for you, it's
not for me and should not be for any pilot.

The USA, where Darryl flies, does not have a requirement for a
transponder in the 15K to 18K airspace.

Can someone explain where the reason for the 15,000' limit for the lower
power transponders? It seems rather arbitrary to a USA pilot.

--
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

On Mar 5, 8:44*am, John Smith wrote:
If you ever want to climb above 15,000 ft in an airspace where a
tansponder is mandatory (which I do regularly), then you are just plain
illegal with the TT21. This may be "fairly meaningless" for you, it's
not for me and should not be for any pilot.

Saying something is "illegal" is a fairly useless statement. A lot of
things are illegal, ranging from driving at 60 in a 55 zone and on up.

I think you need to explain:

- what is the likely safety implication of flying above 15000 with a
TT21?

I suspect the answer is "none whatsoever".


- what is the penalty for being caught doing so? What is the chance of
being caught?

I don't know the answer to the first part but I think I can guess the
second.

In article Bruce Hoult writes:
On Mar 5, 8:44=A0am, John Smith wrote:
If you ever want to climb above 15,000 ft in an airspace where a
tansponder is mandatory (which I do regularly), then you are just plain
illegal with the TT21. This may be "fairly meaningless" for you, it's
not for me and should not be for any pilot.

Saying something is "illegal" is a fairly useless statement. A lot of
things are illegal, ranging from driving at 60 in a 55 zone and on up.

I think you need to explain:

- what is the likely safety implication of flying above 15000 with a
TT21?

I suspect the answer is "none whatsoever".


Unless, of course, the encoder actually cannot encode significantly above
that altitude.

Or, if it encodes incorrect values, resulting in that airliner hitting you
and going down with all aboard. That will look about as bad as not having
had a transponder in the first place.


- what is the penalty for being caught doing so? What is the chance of
being caught?

The first part probably depends on how you are caught.

Alan

On Mar 4, 9:52*pm, (Alan) wrote:
In article Bruce Hoult writes:

On Mar 5, 8:44=A0am, John Smith wrote:
If you ever want to climb above 15,000 ft in an airspace where a
tansponder is mandatory (which I do regularly), then you are just plain
illegal with the TT21. This may be "fairly meaningless" for you, it's
not for me and should not be for any pilot.

Saying something is "illegal" is a fairly useless statement. A lot of
things are illegal, ranging from driving at 60 in a 55 zone and on up.

I think you need to explain:

- what is the likely safety implication of flying above 15000 with a
TT21?

I suspect the answer is "none whatsoever".

* Unless, of course, the encoder actually cannot encode significantly above
that altitude.

* Or, if it encodes incorrect values, resulting in that airliner hitting you
and going down with all aboard. *That will look about as bad as not having
had a transponder in the first place.

- what is the penalty for being caught doing so? What is the chance of
being caught?

* The first part probably depends on how you are caught.

* * * * Alan

Nice fear theories but there is no reality here. The encoders in the
Trig transponders are not an issue. The TT21 and TT22 use the same
control head and that is where the encoder is.

Current Mode C/gray code (100' resolution) external encoders operate
to a minimum of 30k feet. More expensive expensive encoders get you to
higher altitudes. And to get into a Mode S/serial encoder (25'
resolution) style encoder typically gets you higher than 30k feet as
standard but most of the Mode S transponders we care about in gliders
come with built in encoders.

For all USA gliders after transponder installation a static system
check (Part 43 Appendix E) is required to ensure both altimeter and
encoder accuracy. Nothing in that static systems tests is specific to
type 1 or 2 transponders--just ask the person doing the test if they
can check to 18,000' or higher just to be sure. (and if a Trig encoder
needs adjusting to meet altimeter accuracy the test operator has to
drive it up to 20,000' anyhow to use the calibration adjustment).

What is important is to get people installing and properly using
transponders where we have high density airline and fast jet traffic.
Not only did Trig (and maybe some other products in Europe who are not
available in the USA) significantly lower the cost and power
requirements of installing Mode S but they also significantly reduced
the cost difference between the Class 2 and Class 1 versions of their
transponders. Other vendors had been using that class 1 vs class 2
requirement to create high artificial price differences between their
transponders (for what were basically the same electronics). Trig's
price difference seems only around $200, so pretty marginal, so there
is less reason to use the Class 2 TT21 if class 1 requirement worries
you. The TT22 will use slightly more power than the TT21. Almost all
glider installations of Trig transponders I am aware of are TT21 and
seem to be doing very well.

Darryl

On 3/4/2011 9:52 PM, Alan wrote:
In Bruce writes:
On Mar 5, 8:44=A0am, John wrote:
If you ever want to climb above 15,000 ft in an airspace where a
tansponder is mandatory (which I do regularly), then you are just plain
illegal with the TT21. This may be "fairly meaningless" for you, it's
not for me and should not be for any pilot.

Saying something is "illegal" is a fairly useless statement. A lot of
things are illegal, ranging from driving at 60 in a 55 zone and on up.

I think you need to explain:

- what is the likely safety implication of flying above 15000 with a
TT21?

I suspect the answer is "none whatsoever".


Unless, of course, the encoder actually cannot encode significantly above
that altitude.

Or, if it encodes incorrect values, resulting in that airliner hitting you
and going down with all aboard. That will look about as bad as not having
had a transponder in the first place.

We need to be sure we are talking about the same regions (country and
altitude). For the USA, Class A airspace starts at 18,000', so for below
that altitude, there is no effective difference between the two classes
of transponders for pilots operating VFR.

If you intend to operate in USA Class A airspace without waiver, then
getting the higher altitude rated transponder makes sense. The extra
cost of the unit is small compared to the ongoing testing requirements
of your transponder, altimeter, and static system, so there is no point
in taking a chance the encoder might not be accurate enough at the high
end (30,000+?).

I am still curious about the differences between the two models, beyond
the obvious one of output power.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz

Am 05.03.11 02:10, schrieb Bruce Hoult:
- what is the likely safety implication of flying above 15000 with a
TT21?

I suspect the answer is "none whatsoever".

The word "suspect" says that you don't know. I don't know either, but I
suspect that there's a reason for the requirement.

Frankly, I simply don't understand this discussion. The price difference
between the TT21 and the TT22 is negligible (list price at Cumulus
Soaring $2195 vs $2395). How would any mentally sane pilot choose to go
illegal for a price difference of just 200 bucks?