TrikePilot Social – Microlight & LSA Trike Flying Community › Forums › HELP! › ADSB-out and ADSB-in requirements and recommendations
March 1, 2019 at 10:28 pm #2059
I am hoping to get advice/recommendations from pilots knowledgeable about these topics. Background: I picked up my new NW Scout XC Apache ~18months ago, but when I ordered it I decided at that time to exclude a mode C transponder as part of the package. Now I need to not only pursue installation of a transponder but also an ADSB transceiver. I have spent some time researching options but figuring out what is best option for my trike is difficult and a bit confusing. So here are a few questions.
1. What is difference between mode C and mode S transponders? and which are appropriate for trikes?
2. Am I correct that 2020 compliance only requires ADSB-out? yet having ADSB-in is only optional?
3. Given I have extremely limited available dash space and need to address these needs in the most compact form possible, what are your recommendations on avionics units to have installed?
I use the iFly 740b GPS that apparently has ability to interface with some ADSB-in equipment like the Stratux RXWX available through the iFly GPS store. They also list the uAvionix echoUAT – ADS-B Transceiver for LSA & EXP which may be an option but in addition to that I guess I would also need a separate mode C or S transponder. I have also looked at the TT21 from Trig Avionics. Description seems to indicate it is both a mode S transponder and provides ADSB transceiver. But if this is only ADSB-out then I would still have to figure out how to get the ADSB-in capability that could interface with my iFly 720b. I really like the idea of a very small compact control head that can be mounted in a 2.25″ hole in dash with remainder of unit mounted elsewhere out of sight.
Any insights, guidance, advice on this would be greatly appreciated. thanks in advance !
March 2, 2019 at 8:31 am #2063
I recently installed a Transponder/Ads-B solution on my trike and had to ask many of the same questions. I am by no means an expert on the subject but can offer some of my own experience and thoughts.
1. There is already much information on Mode C and S transponders and Ads-B on the internet and from manufacturers.
Consider first the airspace you will be flying in. If you only fly in airspace that does not require a Transponder and Ads-B (which is most of the US), then you don’t have to do anything at all! The FAA has a downloadable map that you can overlay on Google Earth to graphically show that information.
Then consider the functionality you will need (realize some functions can be combined or integrated) – Transponder, Ads-B Out, Approved GPS position source, Altitude Encoder, Power Source, User Interface, round wire cable(s), RF coaxial cable(s), Transponder Antenna, Ads-B Out Antenna, GPS Antenna, associated ground planes and optionally Ads-B In and Ads-B In Antenna.
Both transponder types are appropriate for trikes. I like to think of Mode C as “Classic” and Mode S as “Smart”. However, there are advantages and disadvantages, e.g. cost, weight, space, etc. to both so you have to figure out what is best for you and your trike.
Northwing may have already an approved Transponder/Ads-B solution. Check with them, it may save you some time and a Letter Of Authorization (to make modifications to an SLSA trike).
2. 2020 compliance only requires the Ads-B Out functionality. The In functionality is optional but very helpful. There is a lot of traffic out there and I am often amazed at what I don’t see. There are several Ads-B In receivers, e.g. Appareo Stratus, Flight Data Systems Pathfinder, etc,
Most (all?) Ads-B In receivers will link wirelessly to an appropriate app on an Apple or Android device, e.g. Foreflight. The Receiver manufacturer will indicate what apps they are compatible with.
3. Again, there are many trade-offs. If you have an EFIS, it may have an appropriate altitude encoder output that you can use. If your EFIS is the touchscreen variety, you may be able to remote control the transponder via serial interface(s) to the Transponder and Ads-B eliminating the need for a separate panel unit.
Ads-B solutions for Mode C usually have an “RF snooper” that reads and decodes the transponder transmission, and sends the appropriate Ads-B Out transmission at the separate UAT frequency. This is usually a two antenna solution but some Mode C transponders include a “diplexor” that eliminates the UAT antenna.
The Mode S transponder, like the Trig TT21, transmits the Ads-B Out info with the transponder reply message usually indicated as 1090ES (1090 MHz Extended Squitter) thus saving you a separate antenna. The TT21 can be remote controlled with the associated TC20 panel mounted interface which includes a built-in altitude encoder. The GPS input can be provided by a TN70/TN72 GPS receiver or other approved source.
The approved GPS receiver is usually a separate unit with its own antenna. This antenna must be mounted with a view of the sky to be able to see the GPS satellites. This usually means mounting the antenna on an upper external surface as opposed to the bottom or belly external surfaces where the transponder/Ads-B antennas are usually located.
It is usually recommended that all the antennas be mounted at least 1 meter away from each other. Not too hard for keeping the GPS and
Transponder/Ads-B antennas separated. Usually more difficult for individual Transponder and Ads-B antennas. Also, keep all of these antennas away from the COM radio antenna(s).
Also, each Transponder and Ads-B antenna will require a “ground plane” – a sheet of aluminum or copper foil, usually physically mounted on an interior surface. AC 43.13-2B Chapter 3 has useful information about antenna installations and ground planes.
Overwhelmed? I was too. Get more information, reach out to other pilots and manufacturers and ask more questions. Good luck and post the results of your installation.
March 5, 2019 at 6:19 pm #2095
That FAA Airspace map in Google Earth is nice! It allows me to quickly look and see if a place I want to go is out side the local Class C. That isn’t as easy to figure out with a sectional.
If anyone else is interested, the Google Earth KMZ download from the FAA is on this page: https://www.faa.gov/nextgen/equipadsb/research/airspace/
March 7, 2019 at 2:55 am #2102
Thanks Chuck.Snipes for the info on the google earth angle.
March 2, 2019 at 11:55 pm #2067
Thank you Irperkin for your post with lots of useful information. Thankfully vast majority of my flying is in air space that does not require this stuff but because a portion does or may, that is reason for my post. You did not mention what you ended up installing in your trike and are you pleased with choice you made. Yes I was previously in touch with NW on transponder choice but had no interaction on the ADS-B so I will follow up on that. If I recall correctly the mode C transponder they would have installed is a Microair Avionics (same manufacturer as my radio) but it seems to be listed as permanently out of stock (by manufacture and Aircraft Spruce), so perhaps no longer produced. So it appears I will need to find an alternate option as well as ADS-B options, but I will get back in touch on their recommendations. thanks again.
If others have comments/recommendations, I am all ears.
March 3, 2019 at 8:52 am #2069
Joe – I went with the Manufacturer’s standard configuration recommendation consisting of a Sandia STX-165R Mode C transponder, uAvionix echoUAT Ads-B Out/In transceiver (ships with “lollipop” UAT antenna), uAvionix skyFYXX GPS Antenna/Receiver, a Delta-Pop transponder blade antenna. The xpdr is remote controlled from my EFIS via a serial interface so no front panel drilling. The EFIS also provides
the encoded altitude to the xpdr over the same interface. The EFIS also receives the ADS-B In over a separate high speed serial interface for the uplinked traffic display. The UAT also links wirelessly to my iPad so I can also see traffic using the Foreflight app. The xpdr and UAT boxes are mounted securely under the pilot seat. The skyFYXX GPS is mounted just behind the windscreen on top for a view of the satellites. The xpdr antenna is mounted on the belly almost directly under the front seat station with a copper foil ground plane on the interior surface. I painted it to match the color of my trike (allowed by the manufacturer). The UAT antenna is mounted aft on the bottom exterior with its copper foil ground plane on the interior surface. The ground planes follow the curved contours of the interior surface and don’t appear to have any effect on the signals transmitted or received. I had 2 RG-400 RF cables custom fabricated and the wiring was straightforward with help from the trike manufacturer. uAvionix has an app for configuration and monitoring the UAT. Went for test flight and
confirmed everything was working using the FAA ADS-B performance report tool – provide n-number and date/time of flight and FAA provides a performance report. Yes, I am pleased with the result – I fly in Class E airspace between Phoenix Class B and Tucson Class C airspaces with a lot of military and commercial traffic including helicopters and parachute activities.
March 7, 2019 at 2:54 am #2100
Thank you for the additional information Irperkin. I had not previously appreciated the importance of a ground plane and need for all associated antennas to be appropriately placed away from others. Thanks again.
March 3, 2019 at 9:03 am #2071
Since I have an experimental trike I went with the echouat by aAvionix. My biggest issue was where to place the antenna. I already had a mode c transponder with its antenna situated under the motor which puts the adsb-out antenna under my seat. Not the best place but it’s the only place where it made sense. I get a ticking sound coming across my headset. It sorta goes away if I move the headset cord up over my leg? Also be careful of the antennas as they break really easy. I decided to install the transponder and ads-b so it would increase my visibility to other aircraft. I fly in an area with a lot of training aircraft and even though they are good with their traffic call outs over the radio, I can’t seem to find them. With ads-b I still can’t find them half of the time but at least I sorta know where they are.
March 7, 2019 at 2:58 am #2104
Thank you Mark Pansing for the info you shared on your configuration. Yes, I can very much appreciate the greater visibility and awareness that ADS-B can provide.
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