C

ccrawford

Well Known Member
Good afternoon everyone,

I'm installing an aera 560 in my panel, using the GPS out to send a GPS signal to my TT ADI. However, the TT isn't confirming the receipt of the GPS signal.

So, two questions arise:

1) Is there a way to test for the GPS out signal on the signal wire by using a multimeter? I tried checking for voltage (signal wire to ground) but am getting nada when I was expecting a spike in voltage every 1-2 seconds.

2) Does anyone know if the aera 5xx series outputs GPS signals when in simulation mode? Can't seem to find an answer to that either ..

Thanks for any help!
 
The Garmin handhelds do not output (VALID) data in sim mode.

You can connect a laptop to the data wires and use a terminal program to capture the data stream.
 
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Thanks for confirming the no-output in Sim mode, that certainly makes hangar testing much more difficult!
 
mburch said:
Oh really? :)

mcb
Click to expand...


Just trying to keep things simple Matt......

For Matt's sake, let's just say that they don't output valid data at least mine does not.

People are always trying to use the data stream from Garmin handhelds in sim mode. The GPS marks the data as not valid so nothing with software written to only accept valid data will use it.

You can use an o-scope to also see the data on the line. Some multimeters would be too slow to show the data pulses. You would need a true RMS meter and might have to try both the dc and ac settings.

To know for sure, the terminal program on a laptop will allow you to see exactly what is flowing.
 
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In case anyone reads this further, apparently you do get a voltage spike each time the Aera outputs data on the RS232 signal wire. Now that I have a 25ft GPS antenna extension cable (and the GPS antenna outside the hangar) I can get a reliable spike every second on NMEA Fast output.

Can't really tell if my TruTrak ADI is getting the signal, 'cause it waits for 10 mph ground speed before displaying anything, but I feel better.
 
I can't speak to your particular gps, but I've used my gpsIII pilot in sim mode and been able to correctly communicate with my TT Pictorial pilot, APRS transmitter, and PC based mapping software (streets&trips if I recall). The APRS was set up to only transmit valid data, so I assume it's looking for that in the data stream - we all know what assuming does to us though:)

If you take a look at the wiring diagram in the ACK 406 installation manual, you'll find a method of rigging up an LED to light when the gps data is sent. I used the gpsIII to test this too. This doesn't confirm validity, but will confirm data transmission.

Regards,
Rob
Flying -7A since 2007
 
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