Transponder/ADS B recommendations

Fearless Tower

Fearless Tower

Touchdown! Greaser!
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Fearless Tower
Starting to work on my wish list for the Baron's annual coming up in a few months and having flown it for 8 months now, I'm overall pretty happy with the avionics so far. I'm thinking the transponder may be the first thing I upgrade. Any recommendations for meeting the coming ADS B requirement while getting the most bang for the buck? I'm thinking I'd like to be able to have both ADS B in and out capability.
 
I'm starting to think about this too.

It might be useful to understand what's in your cockpit now. I have a certified WAAS GPS GNS430W, so I believe I have an accurate enough position source. Hopefully it has a data output port.

If you want to use ADS-B IN, then I'm guessing you want to install some sort of multi function map display?

If you have a good GPS source, I believe you just need to get that data to a UAT transceiver.

I'm sure Mode A 4096 codes from a transponder and baro-altitude from a barometric encoder needs to get to the UAT transceiver too.

I believe Garmin has transponder/UAT transceiver units all in one package. I don't know who else.

I don't know if there is a requirement for a hard wired 24 Bit ICAO code that puts the aircraft registration on the UAT data stream too. That would be a Mode S like function that lets ATC just interrogate or filter for data specifically from your transponder.

I'm somewhat familiar because I did the analysis for the airline I work for. The GA version is somewhat different than the version for A/C that fly above FL24.
 
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Our shop has been doing many upgrades for Barons and Bonanzas. Many have been getting ADSB installed. What I have been flight testing are GTN650/750 with G500 PFD/MFD coupled to a GTX330 transponder. The transponder can be integrated into the GTN for a very clean panel. Some are upgrading to autopilot as well to an S-Tec 55x.
 
swanberg said:
Our shop has been doing many upgrades for Barons and Bonanzas. Many have been getting ADSB installed. What I have been flight testing are GTN650/750 with G500 PFD/MFD coupled to a GTX330 transponder. The transponder can be integrated into the GTN for a very clean panel. Some are upgrading to autopilot as well to an S-Tec 55x.
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Just to be sure, it's the GTX330ES you want for ADS-B. A regular 330 can be upgraded to the ES though.
 
Mike I said:
Just to be sure, it's the GTX330ES you want for ADS-B. A regular 330 can be upgraded to the ES though.
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That's interesting, it's a 1090 MHZ Extended Squitter Mode S Transponder

I wonder if you gain or loose anything picking 978Mhz vs 1090 Mhz or vice versa, for aircraft operating under FL24.

Mode S is required when TCAS II is installed, nothing wrong with having it if you're not.
 
I wonder if you gain or loose anything picking 978Mhz vs 1090 Mhz or vice versa, for aircraft operating under FL24.
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Most of the rest of the world uses only 1090ES, so if your plane is ever to go overseas that could be a factor.

King makes a 1090ES transponder that is supposed to be an easy upgrade to most existing King transponders.
 
tmyers said:
Fearless, what kind of transponder do you have currently?
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Mine is an older Collins unit.

I currently have a 430 ( non-WAAS) and an older Avidyne MFD that works fine and is compatible with my onboard radar.
 
JimNtexas said:
Most of the rest of the world uses only 1090ES, so if your plane is ever to go overseas that could be a factor.

King makes a 1090ES transponder that is supposed to be an easy upgrade to most existing King transponders.
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I really like the idea of everyone being on 1090. I used to worry about the FAA's proposed relay of UAT to 1090ES users (and vice versa) especially in busy airspace and on the ground taxing where line of sight is marginal.


Having everyone on 1090 might let anybody's ADS-B IN pick them up for their ground taxi application. A diversity antenna sounds good to me too.
 
What's the poor folks to do?

I only have a Mod C transponder and 1 comm radio, I'm certainly not/can't put 40k worth of radios in a 25K aircraft.

I don't think I'm alone.
 
Tom-D said:
What's the poor folks to do?

I only have a Mod C transponder and 1 comm radio, I'm certainly not/can't put 40k worth of radios in a 25K aircraft.

I don't think I'm alone.
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Definitely not alone. My plane is worth more, but it's only gonna fly VFR and I'm also not gonna put $40k of radios in it.
 
Old Geek said:
Definitely not alone. My plane is worth more, but it's only gonna fly VFR and I'm also not gonna put $40k of radios in it.
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I'm all for shuttin up, looking out the window and go. When the picture ain't right, fix it.
 
Old Geek said:
Definitely not alone. My plane is worth more, but it's only gonna fly VFR and I'm also not gonna put $40k of radios in it.
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Mine is too… just saying. Cheap aircraft, expensive radio stack, doesn't make much sense.
 
I recently had a Garmin GDL88 installed. I already had a 430W so that saved me quite a bit of expense. I needed a new encoder as my old one did not have an RS232 output which the GDL88 needs as an altitude input. My transponder is King KT76A which did not need replacing. I get the weather and traffic on the 430 display. Amazing the amount of traffic out there that you don't see and ATC doesn't tell you about.
My installation was done at Avionics Place Rockford, IL (KRFD). Highly recommend.
 
Tom-D said:
Mine is too… just saying. Cheap aircraft, expensive radio stack, doesn't make much sense.
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The unfortunate thing is that the FAA has mandated a very expensive solution to a simple problem. I can buy WAAS enabled GPS pucks from reputable vendors (Garmin, for instance) for $75 all day long. That puck outputs the location and velocity signals necessary to feed an ADS-B out system. Unfortunately, the hoops created for the ADS-B system preclude using a low cost puck and drive you to a GPS 50 times as expensive and 0.000000X% more reliable.

The same is true on the transmitter side of the equation.
 
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kyleb said:
The unfortunate thing is that the FAA has mandated a very expensive solution to a simple problem. I can buy WAAS enabled GPS pucks from reputable vendors (Garmin, for instance) for $75 all day long. That puck outputs the location and velocity signals necessary to feed an ADS-B out system. Unfortunately, the hoops created in for the ADS-B system preclude using a low cost puck and drive you to a GPS 50 times as expensive and 0.000000X% more reliable.

The same is true on the transmitter side of the equation.
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Hence the recent legislation, intended to make it possible for approval of all sorts of gear intended for use in GA light aircraft (and the aircraft themselves) to not be forced through the FAA processes that drive the cost up exponentially.

The new Bendix King KT-74 Mode S ADSB transponder looks interesting for "out" capability, should be available in about one month, and is a slide-in replacement for KT-76A/C and KT-78A transponders, which of course are quite commonly installed:

http://www.aircraftspruce.com/pages/av/adsb/transponder11-12038.php

You need a certified WAAS GPS position source and it needs to be connected to the KT-74 unit in order for it to provide ADSB-out. You can slide it in place and be Mode-S right away. Connecting to a certified WAAS source means some wiring work. You could do that right away, or wait.

I am thinking about going this route, and using a portable receiver for the weather and traffic to be displayed on my ipad and/or Garmin portable, at least for the time being.
 
Pegasus said:
I recently had a Garmin GDL88 installed. I already had a 430W so that saved me quite a bit of expense. I needed a new encoder as my old one did not have an RS232 output which the GDL88 needs as an altitude input. My transponder is King KT76A which did not need replacing. I get the weather and traffic on the 430 display. Amazing the amount of traffic out there that you don't see and ATC doesn't tell you about.
My installation was done at Avionics Place Rockford, IL (KRFD). Highly recommend.
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There are several different GDL88's availabe, which did you get?
 
teejayevans said:
Any idea how long it takes and how much it is?
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No idea how long, but costs $1200, says Garmin's site. I'm not an avionics guy so don't have too much of a clue beyond what I read.
 
kontiki said:
I wonder if you gain or loose anything picking 978Mhz vs 1090 Mhz or vice versa, for aircraft operating under FL24.
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Isn't it FL18, basically Class A? Also, UAT is not permitted anywhere except U.S. You must have 1090ES if you are to fly into another country with ADS-B mandate.

I would definitely not bother with UAT transciever in a Baron. Bonanza, maybe. If you want free weater, get something like GDL-39.
 
kontiki said:
I really like the idea of everyone being on 1090. I used to worry about the FAA's proposed relay of UAT to 1090ES users (and vice versa) especially in busy airspace and on the ground taxing where line of sight is marginal.
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Unfortunately, it's not where things are going, because UAT gear is vastly less expensive than 1090ES gear. Look at any kind of LSA forum. Anyone driving RV-12 or less is looking at UAT, not 1090ES. This includes PPs who fly LSAs for cost reasons.

You know what's really pitiful about all that? Some guys tested pushing weather over 1090ES and found that you could get a decent 512x512 picture even over L.A.. But FAA thought it was not enough. Of course UAT has extra bandwidth, which ES does not, but jeez. We just wasted all that money on supporting 2 bands on the ground, including retransmissions, for some unspecified future applications that may never happen.

Oh and another thing: I tried to implement both, and 1090ES is far simpler than UAT. However, UAT boxes are cheaper. Why is it that?
 
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greghughes said:
.

The new Bendix King KT-74 Mode S ADSB transponder looks interesting for "out" capability, should be available in about one month, and is a slide-in replacement for KT-76A/C and KT-78A transponders, which of course are quite commonly installed:
Click to expand...

So let's say I yank the KT76A in my RV and plug in the -74. In addition to an approved GPS, what other equipment is necessary to meet the 2020 mandate?

Next question - whatever the answer to the first question was, does the -74 meet international spec's or does it only work on the US low altitude frequency?

I ask out of ignorance and from being too lazy to chase down information that I need but which isn't interesting enough (to me) to warrant a lot of primary research.
 
kyleb said:
So let's say I yank the KT76A in my RV and plug in the -74. In addition to an approved GPS, what other equipment is necessary to meet the 2020 mandate?

Next question - whatever the answer to the first question was, does the -74 meet international spec's or does it only work on the US low altitude frequency?

I ask out of ignorance and from being too lazy to chase down information that I need but which isn't interesting enough (to me) to warrant a lot of primary research.
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If you have the approved GPS source and the KT-74 (once TSO'ed and STC published - except that you're experimental so never mind that part hah), you are good for 2020 mandate in the USA. ADSB-out is what's mandated.

The KT-74 is a 1090ES device, rather than UAT, so it's good for international. In fact, their plan was to release internationally first and then deliver to the USA since European approval was expected first. Australia's ADSB-out deadline/mandate is - I think - this year? Europe, if I recall correctly, is 2018.

Video links with some good details:

https://www.youtube.com/watch?v=7c7lW_AkRxs

and

https://www.youtube.com/watch?v=qeZD75Sqb6o
 
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This explanation glosses over the so-called "airdata computer": a box or function that converts GPS data into Extended Squitter bits. It had to be located somewhere. Sometimes it's a separate box, sometimes embedded into GPS. Just to make it more fun, airdata computer may need data from altitude encoder, IIRC.
 
bnt83 said:
There are several different GDL88's availabe, which did you get?
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I got the basic unit as I did not need it to have an internal GPS as I get that information from the 430W. I also did not think that the diversity option was needed.
 
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