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New Transponder for us



 
 
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  #11  
Old December 8th 10, 11:38 PM posted to rec.aviation.soaring
Andy[_1_]
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Posts: 1,565
Default New Transponder for 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
  #12  
Old December 9th 10, 12:03 AM posted to rec.aviation.soaring
jcarlyle
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Posts: 522
Default New Transponder for us

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


  #13  
Old December 9th 10, 01:18 AM posted to rec.aviation.soaring
Dave Nadler
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Posts: 1,610
Default New Transponder for us

On Dec 9, 7:18*am, Darryl Ramm wrote:
On Dec 8, 12:03*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. Of course, you'll only get a 10 year life out of it...


-John


On Dec 8, 2:54 pm, Andy wrote:


Why would anyone buy a mode C transponder when for only a little more
one can buy a mode S unit?


Andy


Actually the 10 year life is not completely accurate, even if I agree
a bit with probably the sentiment behind it. I just don't want any
glider pilots with Mode C transponders to think their transponders
have an abslute hard limit where they stop being useful in 10 years.

Mode C transponders are usable it the USA well beyond 10 years - but
to meet the 2020 ADS-B data-out carriage requirement (a requirement
for power aircraft in similar airspace as transponders are required
now) you would need to add a UAT transmitter or replace the
transponder with a Mode S with 1090ES data-out. Right now its
impractical from a cost, STC paperwork hassle (on non-experimental)
and final -B rev compliance requirements on many products, to add ADS-
B data-out to most light aircraft or gliders but you can install a
Trig TT21 and in future update the firmware and add the ADS-B data-out
GPS.

How current aircraft owners manage the transition to the 2020 ADS-B
data-out mandate will be interesting to see - i.e. whether Mode C
equipped aircraft add UAT devices or swap out their transponders to
get new Mode S units with 1090ES data-out. I expect many will take the
transponder upgrade route since it is a chance to refresh older
transponders which they still need to carry (in may owner aircraft)
and older transponders can become a maintenance liability, so why not
refresh both in one box? For newer Mode C transponders there exists
more of an argument to add a UAT device. In the glider community in
the USA with PowerFLARM looking like important and popular technology
Mode S 1090ES data-out is a better technology to consider than UAT
data-out.

Darryl


Don't forget, mode S will use a lot less power
under non-trivial interrogation...
From soggy Oz,
]See ya, Dave
  #14  
Old December 9th 10, 01:51 AM posted to rec.aviation.soaring
Darryl Ramm
external usenet poster
 
Posts: 2,403
Default New Transponder for us

On Dec 8, 4:18*pm, Dave Nadler wrote:
On Dec 9, 7:18*am, Darryl Ramm wrote:



On Dec 8, 12:03*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. Of course, you'll only get a 10 year life out of it...


-John


On Dec 8, 2:54 pm, Andy wrote:


Why would anyone buy a mode C transponder when for only a little more
one can buy a mode S unit?


Andy


Actually the 10 year life is not completely accurate, even if I agree
a bit with probably the sentiment behind it. I just don't want any
glider pilots with Mode C transponders to think their transponders
have an abslute hard limit where they stop being useful in 10 years.


Mode C transponders are usable it the USA well beyond 10 years - but
to meet the 2020 ADS-B data-out carriage requirement (a requirement
for power aircraft in similar airspace as transponders are required
now) you would need to add a UAT transmitter or replace the
transponder with a Mode S with 1090ES data-out. Right now its
impractical from a cost, STC paperwork hassle (on non-experimental)
and final -B rev compliance requirements on many products, to add ADS-
B data-out to most light aircraft or gliders but you can install a
Trig TT21 and in future update the firmware and add the ADS-B data-out
GPS.


How current aircraft owners manage the transition to the 2020 ADS-B
data-out mandate will be interesting to see - i.e. whether Mode C
equipped aircraft add UAT devices or swap out their transponders to
get new Mode S units with 1090ES data-out. I expect many will take the
transponder upgrade route since it is a chance to refresh older
transponders which they still need to carry (in may owner aircraft)
and older transponders can become a maintenance liability, so why not
refresh both in one box? For newer Mode C transponders there exists
more of an argument to add a UAT device. In the glider community in
the USA with PowerFLARM looking like important and popular technology
Mode S 1090ES data-out is a better technology to consider than UAT
data-out.


Darryl


Don't forget, mode S will use a lot less power
under non-trivial interrogation...
From soggy Oz,
]See ya, Dave


Dave is correct that Mode S transponders will consume less power in
some environments where they are being interrogated as a Mode S
transponder since they do not see the extra Mode A/C interrogations
(at least not those from a Mode S capable interrogator) and so need to
transmit fewer replies than a Mode C transponder. However that does
*not* get close to explaining the apparent high power consumption
(1.1 Amp!!) of this Mode C transponder vs. the Trig Mode S
transponder.

The exact details of power consumption in different situations for SSR
radar depends on details of the ATCRBS ground interrogator. The
transponder will still likely get hit by multiple interrogations per
sweep and the individual transmission from the Mode S transponder may
well take more power than that a Mode C transmission. The power
required for a Mode A/C transmission depends on the squawk code
(==pulse pattern) but the power required for the Mode S data-packet
does not change like this.

In complex TCAS I and II environments the Mode S transponder will see
fewer interrogations but even a Mode C transponder will only reply to
a small fraction of the realtively high interrogation rate of a TCAS
system since TCAS uses the "whisper-shout" trick to cause Mode C
transponders within a certain distance range to reply. Its all that
TCAS Mode C interrogation and replies from some of the Mode C
transponders that is a bandwidth hog (and why goign to Mode S only in
the USA might have been a good idea to support ADS-B 1090ES). Mode S
is much more elegant. TCAS discovers the Mode S transponder by its
acquisition squitter (advertising it is there without needing to be
interrogated) and the TCAS interrogator can interrogate Mode S
transponders uniquely without using the whisper-shout hack.

If being interrogated by a Mode C only interrogator (e.g. by GA
aircraftTCAD/TAS systems (which have traditionally not supported Mode
S interrogations) then the Mode S transponder will transmit Mode A/C
replies without any of the Mode S stuff.

Darryl

  #15  
Old December 9th 10, 03:59 AM posted to rec.aviation.soaring
Eric Greenwell[_4_]
external usenet poster
 
Posts: 1,939
Default New Transponder for us

On 12/8/2010 4:51 PM, Darryl Ramm wrote:
However that does
*not* get close to explaining the apparent high power consumption
(1.1 Amp!!) of this Mode C transponder vs. the Trig Mode S
transponder.


According to the brochure I downloaded, the remote version of the unit
only requires 200 ma, instead of 500 (still at 28 volts). That's still
pretty high for a version without the encoder, but it makes me wonder
where the 300 ma is going.

Someone could call the company to find out, but really, I see little
value in it when the Trig is so good. If you want to save some money,
offer to buy a used Becker for, say, $1000-$1200, and get one from
someone that's thinking of upgrading to a Trig.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
  #16  
Old December 9th 10, 04:25 AM posted to rec.aviation.soaring
Grider Pirate
external usenet poster
 
Posts: 238
Default New Transponder for us

Someone could call the company to find out, but really, I see little
value in it when the Trig is so good. If you want to save some money,
offer to buy a used Becker for, say, $1000-$1200, and get one from
someone that's thinking of upgrading to a Trig.

I'm just waiting for Trig to produce a transceiver too.
  #17  
Old December 9th 10, 04:37 AM posted to rec.aviation.soaring
Darryl Ramm
external usenet poster
 
Posts: 2,403
Default New Transponder for us

On Dec 8, 6:59*pm, Eric Greenwell wrote:
On 12/8/2010 4:51 PM, Darryl Ramm wrote:

However that does
*not* get close to explaining the apparent high power consumption
(1.1 Amp!!) of this Mode C transponder vs. the Trig Mode S
transponder.


According to the brochure I downloaded, the remote version of the unit
only requires 200 ma, instead of 500 (still at 28 volts). That's still
pretty high for a version without the encoder, but it makes me wonder
where the 300 ma is going.

Someone could call the company to find out, but really, I see little
value in it when the Trig is so good. If you want to save some money,
offer to buy a used Becker for, say, $1000-$1200, and get one from
someone that's thinking of upgrading to a Trig.

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


Either Sandia is quoting numbers for an encoder with heater full on
(unusual to do so), or they have an inefficient encoder design or
their control head draws a surprising large amount of power (for
something with an OLED display), or some combination of all of that.

A good rough number for steady state consumption for an ACK-30 encoder
(what most of us with Mode C transponders in gliders use today) is a
bit over 60mA @ 12VDC without the heater on. Heater full on they can
draw 400mA @ 12VDC (luckily the heater should not be on often in
usual use - but if you are flying in wave especially make sure the
encoder box is insulated and protected from drafts).

But even then even if you were compete nuts and wanted to spend money
on a Mode C transponder today the headless version of this transponder
is still not an option until somebody has a controller that can
control it.

BTW the heater in the encoder built into the Trig TT21/22 kicks in
starting at 4C down to -25C where it is full on. At its peak it
consumes 1.7 Watts (= 140mA @ 12VDC). Very impressive numbers. Data is
from Trig engineering.

I have a pair of very nice electrical heated boot insoles that I
brought for wave flying and they consume almost the same as the spec
on this Sandia transponder implies it does at 12VDC. Possible since I
have 2 x 18Ah batteries, a engine driven generator, and a large solar
panel in my motor glider... but still if I'm going to just absolutely
burn power for the hell of it its going to be for important stuff like
keeping my feet warm not to run this junk.

Darryl
  #18  
Old December 9th 10, 04:38 PM posted to rec.aviation.soaring
Richard[_9_]
external usenet poster
 
Posts: 551
Default New Transponder for us

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
  #19  
Old December 9th 10, 04:46 PM posted to rec.aviation.soaring
Darryl Ramm
external usenet poster
 
Posts: 2,403
Default New Transponder for us

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
  #20  
Old December 9th 10, 04:58 PM posted to rec.aviation.soaring
Richard[_9_]
external usenet poster
 
Posts: 551
Default New Transponder for us

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
 




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