King KT-78 Transponder

[Tony Condon[_2_]]

King made a version of their KT-76 Transponder with only 150 watts of power
and called it the -78. Im curious if anyone has ever tried to use one of
these in a glider. If so, what sort of power draw did you experience?

Thanks!
-Tony Condon
Cherokee II N373Y

[Peter Purdie[_4_]]

A standard height encoder alone would need more power draw than a modern
transponder with integrated height encoder.

And fitting an ARINC case TPDR into an average glider panel would
compromise the layout of thestuff you actually need on the panel to go
soaring.

At 03:00 30 March 2009, Tony Condon wrote:
>King made a version of their KT-76 Transponder with only 150 watts of
power
>and called it the -78. Im curious if anyone has ever tried to use one
of
>these in a glider. If so, what sort of power draw did you experience?
>
>Thanks!
>-Tony Condon
>Cherokee II N373Y
>

[Darryl Ramm]

On Mar 30, 1:30*am, Peter Purdie > wrote:
> A standard height encoder alone would need more power draw than a modern
> transponder with integrated height encoder.
>
> And fitting an ARINC case TPDR into an average glider panel would
> compromise the layout of thestuff you actually need on the panel to go
> soaring.
>
> At 03:00 30 March 2009, Tony Condon wrote:
>
> >King made a version of their KT-76 Transponder with only 150 watts of
> power
> >and called it the -78. *Im curious if anyone has ever tried to use one
> of
> >these in a glider. *If so, what sort of power draw did you experience?
>
> >Thanks!
> >-Tony Condon
> >Cherokee II N373Y


I would also discourage people from wasting time with older
transponders for reasons including power consumption, reliability,
vendor support and repairability, space, lack of encoder altitude
display, etc. Modern transponders are all solid state, the KT-76/78
uses a cavity tube, you know--glowing metal filament, all that stuff,
this will use a good fraction of an amp just to run the filament. The
power consumption is going to be ugly.

However the statement on encoder power consumption is just not
accurate. A "standard height encoder" most definitely will *NOT* draw
more power than a modern transponder with intergrated height encoder.

The "standard" aka most common encoder used in sailplanes is the
ACK-30, certainly in the USA it is almost exclusively used. Chosen for
it's low power consumption and low cost. Nominal consumption quoted by
the manufacturers is is 60mA @ 14VDC. Consumption with the heater off
is measured at less than 10mA @ 12 V and from my measurements even on
typical soaring days the average consumption is well below the
nominal. If the encoder is not exposed to cold air leaks and you don't
fly in cold wave etc. then a consumption of a few tens of mA is
probably correct for power budget purposes. And what's more the ACK-30
is pretty low cost around $150-$200.

A typical modern low power consumption transponder with internal
encoder is the Trigg TT-250. The vendor specs for that transponder are
a impressive 280mA @14V nominal consumption. That is still over an
order of magnitude higher than the ACK-30 encoder alone (the Trigg
will be closer to it's claimed nominal power consumption than the
ACK-30 encoder which has it's specs padded to account for heater duty
cycle).

The reason for being pedantic is I don't want people thinking that an
external encoder necessarily implies large power consumption. Some
may, but most gliders will be using an ACK-30 if the installation has
an external encoder.

Always be careful of comparing specs. There is no standard way of
measuring/quoting typical power consumptions and different vendors may
quote different specs. Here are some --

Internal Encoder
Trig TT-250 130W (nominal at connector) Mode-S 0.28A typical @ 14V

External encoder
Mode-S Becker BXP 6401-2-(01) 140W (nominal at connector) 370mA
typical @ 50 replies/sec @ 14V
Mode-C Becker ATC 4401-1-175 175W (nominal at connector) 700mA max @
14V, less than 400mA @ 12V typical measured in actual use (i.e pretty
much the same as the BXP 6401-2-(01) claimed specs)
Mode-C Microair T2000SFL (200W nominal at connector) 150-200mA @ 14V

Stand Alone Encoder
AKC-30 Encoder, warm up current ~420mA @ 14VDC operating current 60mA
@ 14VDC, heater off less than 10mA

The Becker ATC 4401-1-175 is probably the most popular transponder in
the USA and my personal favorite. It suffers on paper in that it's
power consumption quoted is a maximum and well above the typical you
will see. For an actively interrogated transponder in real use I'd
budget about 400mA plus encoder for the 4401-1-175. For the
foreseeable future I have no problem installing a Mode-C transponder
in the USA, Europe of course is a different story with Mode-S. I
expect Mode-S transponder prices to fall in the USA, driven by
European adoption and increasing competition from vendors like Trigg.
I'd like to see/play with the Trigg Mode-S. All these transponders are
in a useful power consumption range for typical sailplane
installations. I personally would not use power consumption as the
differentiator to decide between them. But how important that is for
you depends on you glider power budget/flight profile etc. (do the
math).

And as a final reminder, measuring or understanding quoted power
consumption can be tricky, as it depends on the SSR interrogation
rate and may or may not include the encoder draw since the power for
the encoder is typically supplied through the transponder. Some
manufactures may quote a total power consumption with their specified
encoder. Initial encoder power consumption (i.e. what you will measure
if you just turn the unit on) is often dominated by the heater start
up current, which will be a lot higher than typical power
consumption.

Darryl

[Tony Condon[_2_]]

Darryl,

thanks for the constructive reply. My main limitation right now is cash
on hand. Theres a chance i could squeek by if i dumped the money to put a
new transponder in the glider. I definitely understand the benefit of
going with a new solid state device vs. an old transponder. I know this
from many hours of flying in cessnas with antique transponders :)

Im having a hard time justifying going broke to put nearly $2000 into a
$5000 glider, when i could possibly get by with a setup for $500, even if
i need a bigger battery.

Im looking at 4-5 hr flights below 10K feet. I dont need super long
duration or super cold weather ability. My main concern is just getting
up and away from the gliderport without getting waxed by a KC-135 or the
multitude of airliners, business jets, and other airplanes swarming
about.

At 13:09 30 March 2009, Darryl Ramm wrote:
>On Mar 30, 1:30=A0am, Peter Purdie wrote:
>> A standard height encoder alone would need more power draw than a
modern
>> transponder with integrated height encoder.
>>
>> And fitting an ARINC case TPDR into an average glider panel would
>> compromise the layout of thestuff you actually need on the panel to go
>> soaring.
>>
>> At 03:00 30 March 2009, Tony Condon wrote:
>>
>> >King made a version of their KT-76 Transponder with only 150 watts of
>> power
>> >and called it the -78. =A0Im curious if anyone has ever tried to use
>one
>> of
>> >these in a glider. =A0If so, what sort of power draw did you
>experience?
>>
>> >Thanks!
>> >-Tony Condon
>> >Cherokee II N373Y
>
>
>I would also discourage people from wasting time with older
>transponders for reasons including power consumption, reliability,
>vendor support and repairability, space, lack of encoder altitude
>display, etc. Modern transponders are all solid state, the KT-76/78
>uses a cavity tube, you know--glowing metal filament, all that stuff,
>this will use a good fraction of an amp just to run the filament. The
>power consumption is going to be ugly.
>
>However the statement on encoder power consumption is just not
>accurate. A "standard height encoder" most definitely will *NOT* draw
>more power than a modern transponder with intergrated height encoder.
>
>The "standard" aka most common encoder used in sailplanes is the
>ACK-30, certainly in the USA it is almost exclusively used. Chosen for
>it's low power consumption and low cost. Nominal consumption quoted by
>the manufacturers is is 60mA @ 14VDC. Consumption with the heater off
>is measured at less than 10mA @ 12 V and from my measurements even on
>typical soaring days the average consumption is well below the
>nominal. If the encoder is not exposed to cold air leaks and you don't
>fly in cold wave etc. then a consumption of a few tens of mA is
>probably correct for power budget purposes. And what's more the ACK-30
>is pretty low cost around $150-$200.
>
>A typical modern low power consumption transponder with internal
>encoder is the Trigg TT-250. The vendor specs for that transponder are
>a impressive 280mA @14V nominal consumption. That is still over an
>order of magnitude higher than the ACK-30 encoder alone (the Trigg
>will be closer to it's claimed nominal power consumption than the
>ACK-30 encoder which has it's specs padded to account for heater duty
>cycle).
>
>The reason for being pedantic is I don't want people thinking that an
>external encoder necessarily implies large power consumption. Some
>may, but most gliders will be using an ACK-30 if the installation has
>an external encoder.
>
>Always be careful of comparing specs. There is no standard way of
>measuring/quoting typical power consumptions and different vendors may
>quote different specs. Here are some --
>
>Internal Encoder
>Trig TT-250 130W (nominal at connector) Mode-S 0.28A typical @ 14V
>
>External encoder
>Mode-S Becker BXP 6401-2-(01) 140W (nominal at connector) 370mA
>typical @ 50 replies/sec @ 14V
>Mode-C Becker ATC 4401-1-175 175W (nominal at connector) 700mA max @
>14V, less than 400mA @ 12V typical measured in actual use (i.e pretty
>much the same as the BXP 6401-2-(01) claimed specs)
>Mode-C Microair T2000SFL (200W nominal at connector) 150-200mA @ 14V
>
>Stand Alone Encoder
>AKC-30 Encoder, warm up current ~420mA @ 14VDC operating current 60mA
>@ 14VDC, heater off less than 10mA
>
>The Becker ATC 4401-1-175 is probably the most popular transponder in
>the USA and my personal favorite. It suffers on paper in that it's
>power consumption quoted is a maximum and well above the typical you
>will see. For an actively interrogated transponder in real use I'd
>budget about 400mA plus encoder for the 4401-1-175. For the
>foreseeable future I have no problem installing a Mode-C transponder
>in the USA, Europe of course is a different story with Mode-S. I
>expect Mode-S transponder prices to fall in the USA, driven by
>European adoption and increasing competition from vendors like Trigg.
>I'd like to see/play with the Trigg Mode-S. All these transponders are
>in a useful power consumption range for typical sailplane
>installations. I personally would not use power consumption as the
>differentiator to decide between them. But how important that is for
>you depends on you glider power budget/flight profile etc. (do the
>math).
>
>And as a final reminder, measuring or understanding quoted power
>consumption can be tricky, as it depends on the SSR interrogation
>rate and may or may not include the encoder draw since the power for
>the encoder is typically supplied through the transponder. Some
>manufactures may quote a total power consumption with their specified
>encoder. Initial encoder power consumption (i.e. what you will measure
>if you just turn the unit on) is often dominated by the heater start
>up current, which will be a lot higher than typical power
>consumption.
>
>Darryl
>
>
-Tony Condon
Cherokee II N373Y

[Eric Greenwell]

Darryl Ramm wrote:

> Always be careful of comparing specs. There is no standard way of
> measuring/quoting typical power consumptions and different vendors may
> quote different specs. Here are some --
>
> Internal Encoder
> Trig TT-250 130W (nominal at connector) Mode-S 0.28A typical @ 14V
>
> External encoder
> Mode-S Becker BXP 6401-2-(01) 140W (nominal at connector) 370mA
> typical @ 50 replies/sec @ 14V
> Mode-C Becker ATC 4401-1-175 175W (nominal at connector) 700mA max @
> 14V, less than 400mA @ 12V typical measured in actual use (i.e pretty
> much the same as the BXP 6401-2-(01) claimed specs)
> Mode-C Microair T2000SFL (200W nominal at connector) 150-200mA @ 14V

I know the brochure quotes this, but the two installed current
measurements I heard of were over 300 ma on the ground, no
interrogations. Do other pilots have actual installed measurements for
their Microair transponders?

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[Bob Kuykendall]

On Mar 29, 8:00*pm, Tony Condon >
wrote:
> King made a version of their KT-76 Transponder with only 150 watts of power
> and called it the -78. *Im curious if anyone has ever tried to use one of
> these in a glider. *If so, what sort of power draw did you experience?

Tony, one trick to consider is to watch for a used Garmin GTX320. It
is a solid-state unit (no cavity tube) with fairly low power draw, and
you'll often find them on the used market where someone is swapping
out for a GTX327. I got one for $800 a while back and shoehorned it
and an ACK encoder into my HP-18 panel. The whole setup cost a bit
under $1K.

Thanks, Bob K

[Eric Greenwell]

Bob Kuykendall wrote:
ese in a glider. If so, what sort of power draw did you experience?
>
> Tony, one trick to consider is to watch for a used Garmin GTX320. It
> is a solid-state unit (no cavity tube) with fairly low power draw, and
> you'll often find them on the used market where someone is swapping
> out for a GTX327. I got one for $800 a while back and shoehorned it
> and an ACK encoder into my HP-18 panel. The whole setup cost a bit
> under $1K.

What current draw to you measure? The specifications indicate about 1
amp maximum, still a lot compared to the Becker, etc.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[Bob Kuykendall]

On Mar 30, 7:06*pm, Eric Greenwell > wrote:

> What current draw to you measure? The specifications indicate
> about 1 amp maximum, still a lot compared to the Becker, etc.

I don't have good measurements of typical power draw, but it doesn't
seem to be anywhere near a full amp.

Thanks, Bob K.

[[email protected]]

Bob,

I've got an HP-11A (N9821) and was interested in your post about the GTX 320 and the ACK 30 encoder. Do you have any photos of the installation you can share?

Thanks,

Mark J

[[email protected]]

I have a GTX320 and an ACK encoder available. The ACK is advertised on glidersource.com, but I didn't list the GTX320. Contact me through that ad, if interested. Please be patient on the reply. I'm going to be down for a couple of days, but I'll get back to you as soon as I can.

C. Czech

[[email protected]]

Gliders are exempt from transponder requirements. However, having a transponder makes me wonder with the change in 2020 in the US to ADS-B, will any of these Mode C transponders still be allowed/useful?

[[email protected]]

Anyone thinking of installing a transponder in a plane that currently doesn't have one in an area (esp US or EU) that supports ADS-B should seriously consider getting one with Mode-S, and that can participate in ADS-B http://en.m.wikipedia.org/wiki/ADS-B

--bob

[[email protected]]

Yes they will still be allows red, but the question is what will ATC do with them?

Here's an FAA doc that describes the 2020 changes. It doesn't say anything about gliders, but it does talk about LSA and uncertified installs : https://www.faa.gov/nextgen/ga/media/Safety-Briefing-ADS-B.pdf

--bob

[Tony[_5_]]

Interesring that this thread came back to life. So now the rest of the story...

I did buy a Garmin 320 but never installed it. I later picked up a Microair T2000 for a good deal on an insurance salvage auction and installed it in the Cherokee. It works really good and I use it often to get radar service from Wichita Approach and occasionally fly in or over the Class C.

I liked it so much that we bought another T2000 from Europe and put it in the Std Cirrus. I've also spent some time in the Class C in that glider as well as getting radar services from Longview (Texas) Approach on my way to Louisiana last April.

[Dave Nadler]

On Tuesday, January 20, 2015 at 7:19:04 AM UTC-5, wrote:
> Anyone thinking of installing a transponder in a plane that currently doesn't
> have one in an area (esp US or EU) that supports ADS-B should seriously
> consider getting one with Mode-S, and that can participate in ADS-B
> http://en.m.wikipedia.org/wiki/ADS-B
>
> --bob

For more info, see: http://www.gliderpilot.org/FLARM-Transponders
Enjoy, Best Regards, Dave

[Dan Marotta]

It does mention aircraft certificated without electrical systems, which
I believe means "engine driven" electrical systems. It's pretty
convoluted (as usual), but here's a part of the text:

(e)The requirements of paragraph (b) of this section do not apply to any
aircraft that was not originally certificated with an electrical system,
or that has not subsequently been certified with such a system
installed, including balloons and gliders (my emphasis). These aircraft
may conduct operations without ADS-B Out in the airspace specified in
paragraphs (d)(2) and (d)(4) of this section. Operations authorized by
this section must be conducted—
(1)Outside any Class B or Class C airspace area; and
(2)Below the altitude of the ceiling of a Class B or Class C airspace
area designated for an airport, or 10,000 feet MSL, whichever is lower.

Time will tell but I'm glad I installed a Trig TT-22.

On 1/20/2015 5:29 AM, wrote:
> Yes they will still be allows red, but the question is what will ATC do with them?
>
> Here's an FAA doc that describes the 2020 changes. It doesn't say anything about gliders, but it does talk about LSA and uncertified installs : https://www.faa.gov/nextgen/ga/media/Safety-Briefing-ADS-B.pdf
>
> --bob

--
Dan Marotta

[kirk.stant]

On Tuesday, January 20, 2015 at 10:44:58 AM UTC-6, Dan Marotta wrote:

> Time will tell but I'm glad I installed a Trig TT-22.

That's nice, but aren't you going to get bored staying below 10,000 ft? Because that's what you will have to do to stay legal, unless you have an approved WAAS GPS hooked up to that nice Trig of yours!

And right now, there is only one approved WAAS GPS for the TT-22, the FreeFlight WAAS 1201, and it isn't cheap at $2900. Just hooking the Trig to your logger's GPS won't hack it! Hopefully that situation will get better as 2020 approaches.

Or you can double up and get ADS-B out, and go up to 18,000...

Thank you FAA for a really botched system!

Kirk
66

[Dan Marotta]

Thanks Kirk,

I've already looked at the FreeFlight system. Then there's this:
http://www.trig-avionics.com/tn70.html. Either way, I've still got
almost 5 years to squirrel away my pennies. I'll only need to save
about $12/week to make that goal.

Where I live, 10K won't do. The way I read it (and I am neither a
lawyer nor did I play one on TV), according to CFR 91.225 (d)(4) states:

(4)Except as provided in paragraph (e) of this section, Class E airspace
within the 48 contiguous states and the District of Columbia at and
above 10,000 feet MSL (my emphasis), excluding the airspace at and below
2,500 feet above the surface; and

And CFR 91.225 (e)(2) states:

(e)The requirements of paragraph (b) of this section do not apply to any
aircraft that was not originally certificated with an electrical system,
or that has not subsequently been certified with such a system
installed, including balloons and gliders (my emphasis). These aircraft
may conduct operations without ADS-B Out in the airspace specified in
paragraphs (d)(2) and (d)(4) of this section. Operations authorized by
this section must be conducted—
(1)Outside any Class B or Class C airspace area (no problem for most of
us glider pilots); and
(2)Below the altitude of the ceiling of a Class B or Class C airspace
area designated for an airport, or 10,000 feet MSL, whichever is lower.
(This seems to conflict with Para (4) above unless the meaning regards
within the boundaries of the Class B or Class C airspace.)


(at and above 10,000' MSL) and (e) (gliders are exempt). Gotta read
more closely and lobby the SSA and AOPA. Maybe get a hydrogen fuel cell
to power all this crap! :-D

Still to be considered are ADS-B In and the necessary display technology
but I don't think that's required and, out in the middle of nowhere
where I fly, I don't think I need to be concerned.

Dan

On 1/20/2015 10:52 AM, kirk.stant wrote:
> On Tuesday, January 20, 2015 at 10:44:58 AM UTC-6, Dan Marotta wrote:
>
>> Time will tell but I'm glad I installed a Trig TT-22.
> That's nice, but aren't you going to get bored staying below 10,000 ft? Because that's what you will have to do to stay legal, unless you have an approved WAAS GPS hooked up to that nice Trig of yours!
>
> And right now, there is only one approved WAAS GPS for the TT-22, the FreeFlight WAAS 1201, and it isn't cheap at $2900. Just hooking the Trig to your logger's GPS won't hack it! Hopefully that situation will get better as 2020 approaches.
>
> Or you can double up and get ADS-B out, and go up to 18,000...
>
> Thank you FAA for a really botched system!
>
> Kirk
> 66

--
Dan Marotta

[Darryl Ramm]

Kirk

You are misreading the 14 CFR 91.225 ADS-B requirements here. The wording is awful but there is no general 10,000' limit as you imply. 14 CFR 91.225 (e)(2) states "Below the altitude of the ceiling of a Class B or Class C airspace area designated for an airport, or 10,000 feet MSL, whichever is lower." The later parts of that sentence apply to the situation in the earlier part, so it's below 10,000' (or the ceiling of class B or C) airspace when flying within the lateral constraints of class B or C airspace. Yep, you would have to work hard to write this sentence worse than it is currently...

And another way to be sure of this is the wording here is effectively identical to the transponder exemptions for aircraft without an engine drive electrical system provided by 14 CFR 91.215 and nobody thinks gliders without transponders are restricted to flight below 10,000'.

So basically in both cases think of this as aircraft certified without an electrical systems... your aircraft is exempt from some of transponder and ADS-B carriage requirements but you still can't (without special arrangement) fly in Class C or B airspace without a transponder, and on and after 2020 also without ADS-B Out. Mode-S veils do not apply to that aircraft, but when within the lateral bounds of Class B or C airspace you must still remain below the Class B or C airspace ceiling or 10,000' whichever is lower.

And yes that would mean currently an approved ADS-B install, not come cobbled together system with COTS GPS. In other situations there may be some light at the end of the tunnel with the FAA releasing TSO-C199 "Traffic Awareness Beacon System (TABS)"... basically for gizmos that look like low-power Mode-S transponders, but don't quite implement the full transponder feature set, and optionally have some ADS-B 1090ES data-out capability... and they can use simpler/cheaper GPS systems than currently required for ADS-B data-out. TSO-C199 systems are intended for traffic awareness/avoidance compatibility and not for ATC use so I'd not expect anything say related to Class C or B airspace restrictions to change if an aircraft was equipped with a TSO-C199 compatible system. It is too early to tell whether any manufacturers will really get behind the work needed to support getting a system approved.

[Tony I'm glad to see you made progress by following my earlier "helpful" advice :-)]

Darryl


On Tuesday, January 20, 2015 at 9:52:33 AM UTC-8, kirk.stant wrote:
[snip]
> That's nice, but aren't you going to get bored staying below 10,000 ft? Because that's what you will have to do to stay legal, unless you have an approved WAAS GPS hooked up to that nice Trig of yours!
>
> And right now, there is only one approved WAAS GPS for the TT-22, the FreeFlight WAAS 1201, and it isn't cheap at $2900. Just hooking the Trig to your logger's GPS won't hack it! Hopefully that situation will get better as 2020 approaches.
>
> Or you can double up and get ADS-B out, and go up to 18,000...
>
> Thank you FAA for a really botched system!
>
> Kirk
> 66

[Darryl Ramm]

Mode-S Veil, sigh clearly I meant mode C-Veil.

And now I have another ADS-B induced migraine...

[kirk.stant]

On Tuesday, January 20, 2015 at 1:45:05 PM UTC-6, Darryl Ramm wrote:
> Mode-S Veil, sigh clearly I meant mode C-Veil.
>
> And now I have another ADS-B induced migraine...

Well how else can we usefully pass the winter... ;^)

Glad you corrected me on the 10k altitude limit - it did seem a bit restrictive, but as you said, decoding the FARs can be challenging!

Seems to me the best option for gliders everywhere is at least a PowerFlarm (so I can see Mode C/S and other PF gliders), and in areas of high traffic or high altitude flight, a good Mode S transponder (so they can see you). Got the first, working on the second.

Kirk
66

[Darryl Ramm]

On Wednesday, January 21, 2015 at 8:58:28 AM UTC-8, kirk.stant wrote:
> On Tuesday, January 20, 2015 at 1:45:05 PM UTC-6, Darryl Ramm wrote:
> > Mode-S Veil, sigh clearly I meant mode C-Veil.
> >
> > And now I have another ADS-B induced migraine...
>
> Well how else can we usefully pass the winter... ;^)

And so far no PW-5 were harmed in this thread...