SV-XPNDR-261 : questions about altitude-pressure

[vivianb]

Hi,

I am trying to find the best solution for an ADS-B compliant solution for stratospheric balloons.
SV-XPNDR-261 transponder could be a good choice :
- TSO-C166B certified (refers to DO-260B)
- Class 1 (125watt), mandatory for aircraft operarting above 15000ft
- light : less than 400g.

Annex 2 of ICAO Rules of the Air mentionnes that an heavy unmanned balloon shall not operate in an area where ground based ADS-B equipement is in use, unless it is equipped with pressure altitude reporting capability.

Three precise questions:
1) Altitude encoding
I did not find in the Dynon litterature how to interface the transponder with an altitude encoder.
For example, for the Trig TT22, altitude encoding is done by the interface TC20.
2) What is the maximum altitude encoding the transponder does support ? I know it depends on if the full gray code is supported.
3) Environnemental conditions : qualification according to DO-160 section 4.1 Altitude.
The qualification level regarding section 4.1 of DO-160 is not specified in Dynon litterature.
Generally, transponders are tested to category C1-35000ft-(it is the cas of TT22) or category D1-50000ft
And for Dynon transponders?
The need for stratospheric ballons would be an environmental testing up to 60000ft but, at time present, I did not find a certified transponder qualified up to 60000ft.

Thanks in advance.
rgds
Vivian

 

[Dynon]

The transponder is an integrated part of our SkyView system, and therefore our SV-XPNDR-261 requires a full SkyView installation to function. It is currently only suitable for use light aircraft (experimental, Light Sport) use. For a variety of reasons - including the fact that SkyView is only able to provide altitude to 30,000 feet - it would not be suitable for your application. You might see if Trig themselves has advice on your specific application. Our SV-XPNDR-261 is actually a custom design that is made in partnership with Trig.