ADSB visibility with non certified GPS

On Monday, October 2, 2017 at 2:47:00 PM UTC-7, wrote:
On Sunday, October 1, 2017 at 4:24:46 PM UTC-5, Ramy wrote:
While we at it, will be good to know if we can connect any non TSO amplified GPS antenna to the TN72 and save an additional $300, and if anyone has a recommendation.

Ramy


I wondered about this too because the TA70 is HUGE and really designed for external mounting.

I also found this quote online related to the TN72. "Where a non-TSO antenna is used, the antenna must include an integral amplifier with gain of not less than 20dB."

Below are some code definitions, and then one data set each from a TN70 Antenna and then a GPS antenna borrowed from a CAI 302. I replaced my specific coordinates with "z", but the rest of the data looks to be there. I googled $RAIM, but didn't find anything on that other than it's related to GPS accuracy, etc.



$GPGGA - Global Positioning System Fix Data
$GPVTG - Track made good and ground speed
$GPGSA - GPS DOP and active satellites
$GPZDA - Date & Time
$GPGLL - Geographic position, latitude / longitude
$GPGSV - GPS Satellites in view
$GPRMC - Recommended minimum specific GPS/Transit data


TA70 Antenna
$RAIM,128443,103224,012335,012471,020000,020000,00 0887,000896,111,5,11111111*36
$GPGGA,202757.00,zzzz.zzzzz,N,zzzzz.zzzzz,W,1,06,2 .44,-8.2,M,,M,,*73
$ACVT,1,W,000012,N,000004,U,000014*53
$GPVTG,291.94,T,,M,0.026,N,0.048,K,A*32
$GPGSA,A,3,13,15,20,21,18,10,,,,,,,3.47,2.44,2.47, 1*13
$GPZDA,202757.00,02,10,2017,,*64
$GPGLL,zzzz.zzzzz,N,zzzzz.zzzzz,W,202757.00,A,A*7B
$GPGSV,2,1,06,13,35,048,33,15,68,069,49,20,50,033, 48,21,52,330,47,1*6D
$GPGSV,2,2,06,18,44,285,47,10,17,264,38,1*6B
$GPRMC,202758.00,A,zzzz.zzzzz,N,zzzzz.zzzzz,W,0.04 4,261.96,021017,,,A,V*08

CAI 302 Antenna
$RAIM,150175,112197,013718,013213,020000,020000,00 2021,001947,111,5,11111111*31
$GPGGA,203009.00,zzzz.zzzz,N,zzzzz.zzzzz,W,1,06,2. 54,-10.0,M,,M,,*4E
$ACVT,1,E,000001,N,000004,U,000074*45
$GPVTG,14.73,T,,M,0.008,N,0.015,K,A*00
$GPGSA,A,3,20,13,15,18,21,10,,,,,,,3.53,2.54,2.45, 1*15
$GPZDA,203009.00,02,10,2017,,*69
$GPGLL,zzzz.zzzzz,N,zzzzz.zzzzz,W,203009.00,A,A*7C
$GPGSV,2,1,06,20,49,034,46,13,35,048,28,15,67,067, 46,18,44,286,48,1*66
$GPGSV,2,2,06,21,53,331,41,10,17,265,30,1*66
$GPRMC,203010.00,A,zzzz.zzzzz,N,zzzzz.zzzzz,W,0.06 7,267.22,021017,,,A,V*0E

Is this from an NMEA data from a TN72? All the stuff you are looking at comes from whatever the antennas was connected to and you should not see any change there if both antennas are in the same nominal ballpark (i.e. can receive enough satellites for a fix etc.). But that won't totally prove the antenna is suitable or acceptable to the FAA.

As you point out "where a non-TSO antenna is used, the antenna must include an integral amplifier with gain of not less than 20dB." I expect a TSO antenna is required for install in certified gliders. That big blister hopefully can be hidden under a glareshield, or maybe not. Lots of stuff here needs clarity.