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UAvionics

texdog

Well Known Member
I can’t get the FAA to understand the sniffer concept of ADS-B, Has anyone installed the mod to make it work directly with the 327 transponder?

Thanks
 
RS 232

It is not a mod to have the Uavionics Echo ADSB transceiver work with your Garmin 327 transponder. The connections and settings are shown in the Echo manual. You will simply run the RS 232 serial out line from the 327 to the Echo. I think you will be much happier with this arrangement once complete as the ADSB control is consistent.
 
Fred
The uAvionics page talks about adding a echoMUX for 327/330 installations, is that the setup you have?
Figs
 
I have the Uavionix unit working with my Garmin 327 transponder via sniffer mode. It works perfectly. My understanding is sniffer mode is the preferred method of communication between the transponder and Uavionix unit. If you continue to have problems, the folks at Uavionix are very helpful and should be able to help you get set up. There is an adjustment to the sniffer sensitivity that many people have had to make via the the Uavionix app on your smart phone. IIRC, mine required an adjustment from factory setting of 15 down to 13
 
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mod- well, no

uAvionix has invented a way to read the transponder code and altitude data from the DC power bus. Very clever. Garmin does actually "sniff" the RF signal. They sued uAvionix but lost.
having said all that... I have installed both ways. The FAA doesn't care... just need a good report after a test flight.
The mux is a serial combiner. They will send you one for free. It allows connection to the Garmin transponder which is usually not needed for other transponder brands that have more common serial connections.
Now, after seeing the method used by uAvionix, I still wired to my Sandia transponder and I feel more confident of a 100% signal transfer at all times using RS232 data wire.
I park near a ground station and have had good PAPR reports with as little as a 12 minute flight around the pattern. Most builders will have to use the more common guidance for a test flight.
Best of luck and call uAvionix if confused. They have tech support that is well regarded in the industry.
 
serial connection is better and safer. with serial, altitude data is constantly sent from transponder to ADSB unit for re-transmission. With sniffer, data is only captured / sniffed when the transponder replies to a ground or TCAS request. In low traffic areas, this can be infrequent. No issue in congested airspace. One could argue that in low traffic areas frequent updates are not that important.

Larry
 
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excellent

Larry makes an excellent point that I forgot about. When a transponder is not either replying to an overhead TCAS, or ground radar ping, it is silent.
So the ADSB might revert to GPS altitude... which is often in error by a significant measure.
The data line (just one wire usually) is constant and reliable...
 
Serial connection also allows for true anonymous mode since we aren’t broadcasting the tail number over ads-b while waiting for an interrogation. Instead, with serial, we know we are squawking 1200 immediately, and thus go into anonymous mode immediately.
 
Firware Update

All Fred needs is a firmware update to resolve the issue he's been chasing:

Flight Plan ID (squawk code) is now reported as ‘0000’ instead of ‘Not Available’, prior to the skyBeacon Transponder Monitor detecting a squawk code. This situation can occur in non-radar environments, or prior to achieving radar contact. The change is in accordance with updated TSO deviations as approved for skyBeacon, to better integrate with the operational characteristics of FAA Air traffic control (ATC) systems.
 
Thanks

I’ve been talking to UAvonics and they have been very supportive. I’m a little frustrated because of the FAA response, because there isn’t a real problem. I’m going to get the Mux and install it. I keep telling folks that ADSB isn’t everything, Texas turkey vultures are just as deadly as another airplane. Keep looking outside. It will take some time to get off of the “no service list”. I’ve been able to go wherever I wanted and only one tower noticed it.
 
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MUX not needed

You do not need the MUX unit if you are only going from the 327 to the Echo. The 327 uses 1200 baud which the Echo can accept and that is plenty fast for this use. Only if you need to share the port for traffic and need the higher data speeds will the MUX be necessary.
 
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