NMEA 0183 Buffer/Adapter?

[wilkersk]

My buddy asked me today how he could get GPS position data from the SV-GPS-2020 to his Artex ELT-345. I was wondering, has anyone here had any success using an off-the-shelf buffer like the Actisense Pro-NBF-1? I've heard that I'd need something that could, in addition to just "buffering" the data stream, would also filter out the extra sentences in the data stream and just parse the GGA or GLL sentence to avoid stack overflow errors. Anyone have experience with this?

Also, the Actisense unit is supposed to handle multiple "listeners" (Rx) at any baud rate up to 115,200. Would I connect both the EFIS and the ELT to the buffer? or just have the buffer parallel to the EFIS serial port 5?

 

[mikelupo]

Great topic.
I wonder if you could just take the serial out directly out of the SV-GPS-2020 in parallel with Serial Port 5 in the EFIS without any buffering? Seems maybe you've considered that already. I am interested because I am thinking about replacing my old 121.5 ELT with the same or similar and would like to have GPS input. I have a 430W installed and likely could perhaps just output something on one of the unused serial ports there. Due to the location of the 430 in my panel and the deep dive into THAT wire bundle... this isn't the preferred path forward.

 

[maartenversteeg]

Note that there are limitations in the three serial 430W output ports, as described somewhere deep inside the manuals. I wanted to use the same serial data distribution ("ADS-B+ OUT"?) on two different serial interfaces with different rates and that was not supported by the 430W, so I ended up loosing one of the Dynon serial interfaces to send the data to the ELT that required a different rate than the Dynon used to receive the data from the 430W

 

[wilkersk]

Great topic.
I wonder if you could just take the serial out directly out of the SV-GPS-2020 in parallel with Serial Port 5 in the EFIS without any buffering? Seems maybe you've considered that already. I am interested because I am thinking about replacing my old 121.5 ELT with the same or similar and would like to have GPS input. I have a 430W installed and likely could perhaps just output something on one of the unused serial ports there. Due to the location of the 430 in my panel and the deep dive into THAT wire bundle... this isn't the preferred path forward.

The problem is the baud rate mismatch. That and I'm not totally sure what NMEA sentences are in the data stream besides the ones the ELT-345 is looking for. My idea was to connect the output of the GPS-2020 in parallel from serial port 5 to a buffer and then output that to the ELT at the slower 4,800 baud rate. I think I could buy an off-the-shelf unit, or perhaps build one on Arduino kit that would do this, for cheaper than buying another GPS puck, like the GPS-250, for the ELT. That and was trying to avoid making anymore holes or hanging anymore antennas on the airplane.

The 345 comes preprogrammed for either NMEA @4,800 baud, or AVIATION @ 9600 baud. As I understand it, the SV-GPS-2020 outputs NMEA at 115,200baud which is needed by Skyview for the data intensive fast updates of the EFIS.

 

[wilkersk]

I just ran across the Skyview 3rd Party Device Connection guide. It says "
To configure SkyView:

• Enter SETUP MENU > SYSTEM SETUP > SERIAL PORT SETUP > SERIAL PORT '#'

SETUP and select:

▪ SERIAL IN DEVICE: NONE (does not affect ELT)

▪ SERIAL IN/OUT BAUD RATE: (enter numeric value to match ELT speed)

▪ SERIAL OUT DEVICE: NMEA OUT (BASIC). "

The one thing I didn't try was putting the ELT "RX" to an unused serial port and trying to configure it to output NMEA at 4,800 baud. Anyone know if that would work with a GPS-2020 on serial port 5 as the only position source?

I'm away from home right now, or I'd just go try it.