New small transponder

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

On 3/5/2011 2:04 AM, Eric Greenwell wrote:
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.

If you are flying above 18K in the US without a waiver, don't you need
to be on an IFR flight plan, IFR qualified and current, and in an
aircraft properly equipped and certified for IFR operation? If so, I
suspect that almost all glider operations in the US above 18K require
some form of waiver.

--
Mike Schumann

On 3/5/2011 1:21 PM, Mike Schumann wrote:
On 3/5/2011 2:04 AM, Eric Greenwell wrote:


If you intend to operate in USA Class A airspace without a 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.

If you are flying above 18K in the US without a waiver, don't you need
to be on an IFR flight plan, IFR qualified and current, and in an
aircraft properly equipped and certified for IFR operation?

I'm sure you do need to be operating IFR, and I believe that would
include having the proper class of transponder (but I can't point to the
regulation that says that). That's what I meant by "getting the higher
altitude rated transponder"; i.e., not the up to 15,000' rated one.

If so, I
suspect that almost all glider operations in the US above 18K require
some form of waiver.

I believe that is true, and I also believe it's true you could use your
15,000' rated transponder without any safety impact when using a waiver
to operate over 18,000'. HOWEVER, I don't know what the regulations
require of your transponder installation when operating with a waiver in
Class A.

And, I am still curious about the differences between the two ratings
(above/below 15,000), beyond the obvious one of output power.

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

Here's my summary on the topic...let me know where I am wrong....

In USA you can fly to 17,999' WITHOUT any transponder at all (class E
or G with some exceptions)

If you have a transponder rated only to 15,000", you must have the
transponder "on" and you can only fly to 15,000 (legally)

If you have the "high Power" transponder you can fly up to 17,999
legally

To fly a glider in class A you need "special permission" waiver etc or
whatever.

It is possible to get permission to above 18,000 without a transponder
at all. Wave camps, wave windows, etc.

It is probably more likely to get permission, with a transponder.

Why not just tell the nice man your transponder is only good to 15,000
when you ask permission to go into class A?

If you intend to fly above 15,000, why not just contact ATC and say
"I'm looking to fly above 15,000 but only have the low power
transponder?

If you fly above 15,000 regularly why not just buy the higher power
transponder in the first place?

If you have the old, low power transponder, I am sure it would be easy
to sell, or trade in for high power model!

We installed the trig TT21 in our club glider. One of our airline
pilot guys tried it out and contacted both NY approach, and
Philadelphia approach....both said the signal was very strong.
Probably with a proper install, and antenna the low watt transponder
may actually put out more power into the air than a poorly installed
high power transponder?? Also, we have an agreement to use 1201 code,
so they know it's a glider. Only trouble is, we seldom get that high
around here. State record is around 17,000......maybe somebody went
higher but never claimed..

Cookie

On 3/5/2011 5:47 PM, wrote:
Here's my summary on the topic...let me know where I am wrong....

In USA you can fly to 17,999' WITHOUT any transponder at all (class E
or G with some exceptions)

If you have a transponder rated only to 15,000", you must have the
transponder "on" and you can only fly to 15,000 (legally)

If you have the "high Power" transponder you can fly up to 17,999
legally

To fly a glider in class A you need "special permission" waiver etc or
whatever.

It is possible to get permission to above 18,000 without a transponder
at all. Wave camps, wave windows, etc.

It is probably more likely to get permission, with a transponder.

Why not just tell the nice man your transponder is only good to 15,000
when you ask permission to go into class A?

If you intend to fly above 15,000, why not just contact ATC and say
"I'm looking to fly above 15,000 but only have the low power
transponder?

If you fly above 15,000 regularly why not just buy the higher power
transponder in the first place?

If you have the old, low power transponder, I am sure it would be easy
to sell, or trade in for high power model!

We installed the trig TT21 in our club glider. One of our airline
pilot guys tried it out and contacted both NY approach, and
Philadelphia approach....both said the signal was very strong.
Probably with a proper install, and antenna the low watt transponder
may actually put out more power into the air than a poorly installed
high power transponder?? Also, we have an agreement to use 1201 code,
so they know it's a glider. Only trouble is, we seldom get that high
around here. State record is around 17,000......maybe somebody went
higher but never claimed..

I'm with Darryl on this one: if you think you need a transponder, put
one in your glider, ensure you have the batteries to run it for the
whole flight, and then _Turn_It_On_ when you fly. As long as you are in
the USA, flying VFR, there is no safety or operational reason for
choosing one transponder over the other. The most important thing is
having a transponder. All this fussing over whether it's a Class 1 or
Class 2 is a waste of time.

Buy the Trig 21 or 22, install it, and be happy (we'll all be safer).
ATC will be so pleased you did it that they won't ask you which one it
is, and you don't have to tell them. They don't care, as long as it
shows on their screen.

Or buy one of those old Beckers or Microaires that get traded in - they
are still fine units, and a used one is a lot cheaper than a new one.
Nine years and counting on my 175 watt Becker, so don't wait for mine!

--
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