ADS-B tranmitted via a Mode S TX for the NATS Trial

[bendavis]

Hello,

Has anyone explored wiring their PilotAware box to their transponder for ADS-B output?

I've emailed the NATS people to see if
1. it's not too late to take part in their uncertified GPS trial
2. if they mind that the uncertified device is not a fancy MGL or some other commercial unit like a Garmin but a PilotAware box.

I appreciate the wire connecting them would have to "signed off" by an inspector  / mod approval submitted but it wouldn't be any different to the mod approvals for all the other people taking part in the trials, or would it?

[ianfallon]

I believe and am hoping you're correct.

I understand Lee has 'enabling the RS232 OUT from the PilotAware' on his TODO list at the moment.

[Moffrestorer]

Hi Ben,

I too have been in touch with Adrian Price at NATS. He is aware that I intend using PAW and an iPad to provide the GPS. Doesn't seem to matter in the approvals process, judging from his response.

The LAA/Mod 14 application form calls for data setting SIL and SDA both be set to zero. I've contacted Harry Mendlessohn, who supplied us the Becker BXP6401, to find out how to do this as the Manual makes no mention of this. They weren't aware that anything needs changing on the units and are to get back to me when they have any further info.

Chris

[Welsh Pilot]

Hi Ben,

I too have been in touch with Adrian Price at NATS. He is aware that I intend using PAW and an iPad to provide the GPS. Doesn't seem to matter in the approvals process, judging from his response.

The LAA/Mod 14 application form calls for data setting SIL and SDA both be set to zero. I've contacted Harry Mendlessohn, who supplied us the Becker BXP6401, to find out how to do this as the Manual makes no mention of this. They weren't aware that anything needs changing on the units and are to get back to me when they have any further info.

Chris

What is the serial number on the Becker?
If its below 01999 it is not ADS-B enabled. There is a software and hardware upgrade available.
I also thought the trial had come to an end.....

[AlanB]

The trial has not ended and the LAA have recently announced they are continuing to process the mod to connect GPS and Transponder free of charge.

[Welsh Pilot]

Ok thanks

[bendavis]

If the enabling the PAW RS232 output is not a priority (and I'm not saying it should)  then perhaps a cheap £20 gps like this would get us up and running with ADS-B output.

I think this would do the job for less than £30

http://www.ebay.co.uk/ulk/itm/161819338252

[ianfallon]

Looks like USB rather than DSub 9 pin RS232 ?
I'd like to be sure about the protocol / speed etc too unless it can be configured somehow

[AlanB]

Found this Specification sheet.

http://www.wintec-gps.de/download/wintec_wgm-302_manual.pdf

Usb which through a USB/PS2 connector provides RS232, see end of above.

Not sure that it is a reliable source for the transponder as Im not sure of the workings of the USB/PS2 connector - thought they were just straight wired through of the USB in/out pins but could be wrong.

My TT21 I drive with a standard RS232 input from an AVMap V panel mounted which has the capability.

Another option would be the Garmin series, 795, 695 196 etc. Not sure the Aero can drive anything though not familiar enough for this to be definite.

[JCurtis]

Found this Specification sheet.

http://www.wintec-gps.de/download/wintec_wgm-302_manual.pdf

Usb which through a USB/PS2 connector provides RS232, see end of above.

Not sure that it is a reliable source for the transponder as Im not sure of the workings of the USB/PS2 connector - thought they were just straight wired through of the USB in/out pins but could be wrong.

My TT21 I drive with a standard RS232 input from an AVMap V panel mounted which has the capability.

Another option would be the Garmin series, 795, 695 196 etc. Not sure the Aero can drive anything though not familiar enough for this to be definite.

So it looks like the USB version creates a virtual com port, which is the norm really.  As it requires a driver then it *may* not be plug and play on the Pi, depends on how they create the VCP.  I'd forget the PS/2 version, as you would need to inject 5v power into the signal path between the GPS and Transponder if you wanted to plug it into the DB9 port on a transponder.

There are two different versions, WGM-302 U for USB and WGM-302P for the PS/2 version.

U-Blox5 started in 2008 and doesn't appear to be around any more?

Anything like this, the devil is in the detail.

[Richard]

If you are looking for a GPS to run your Transponder and not use PAW You could try one of these from Evermore they are a marine suppler but have a good veneration of GPS units. I currently use the SA-320 with open rs-232, this runs both the Dynon-100 and now the Trig TT21. All this depends on weather your transponder can supply power to the GPS receiver or does it need to get power from your Avionics Buss  (Reference  to LAA Aircraft)

http://www.evermoregps.ca/index.htm

This is drifting off topic a little and should be on a transponder forum, Sorry.

[bryannortje]

Hi

Looking at the WGM-302P it appears it should work ok direct into a Transponder with a bespoke self made loom. It offers both RS232 and TTL output which should cover most Mode S transponders needs. In my case for the Funke TRT800 I need RS232 (NOT TTL) and baud rate of 4800 input so on the PS2 connector as shown on their wiring dia. I need to supply 5V and a GND to pins 5 and 4 and then connect Pins 1; 3 and 4 (4 being common GND) to the Transponder. Pin 1 is RS-232 RXD and Pin 3 is RS232 TXD. Not being a software guru I suspect from this point its plug and play and no software downloads needed..... this is then a dedicated feed for the Mode S tranny and perhaps gives some redundancy to the systems.

The WGM-302P outputs at 4800 baud rate
The WGM-302U outputs in auto 1200;4800;9200;38400;57600;115200

Ian F; Lee & Jeremy - what you think?

[JCurtis]

You would need the 'P' variant.

Don't get the TTL serial and RS232 levels mixed up, the former will be 0v-5v (or 3.3v) but the latter can be +24v to -24v (normally +/- 12v) for the signals.  Depending on the serial input of the transponder that could cause permanent damage.  Double check everything before plugging in.

If your transponder is expecting 4800 (or can bet set to 4800) then also check if it is the normal 8 bits, No parity, 0 Stop bits (8,N,0) too.  If they match then in theory it should work at the physical layer.

I guess it boils down to how comfortable you are using a unit based on a chipset no longer in production, so of potential dubious origin, to feed your transponder?

[bryannortje]

Hi J

Yes P version only as this gives one an easier connector wiring option. The Funke TRT800 has the option to set the baud rate input level which I believe generally in GPS world is 4800 and so this is the only rate the P puts out.

Totally agree on ensuring RS232 used and not TTL - I gather I can measure that output in V on the respective pins with a multimeter?

For now I am not overly concerned about chipset no longer in production providing the unit works and does so accurately enough - or do I miss understand this and that actually it could be a dodgy GPS source 

[JCurtis]

Hi J

Yes P version only as this gives one an easier connector wiring option. The Funke TRT800 has the option to set the baud rate input level which I believe generally in GPS world is 4800 and so this is the only rate the P puts out.

Totally agree on ensuring RS232 used and not TTL - I gather I can measure that output in V on the respective pins with a multimeter?

For now I am not overly concerned about chipset no longer in production providing the unit works and does so accurately enough - or do I miss understand this and that actually it could be a dodgy GPS source 

You could use a DMM to measure the RS232 vs TTL Serial - I would expect to see bigger numbers on the RS232.  If it has a max hold that may help too. 

My only concern with these things is they say they are using a GPS receiver that is out of production, yet they still keep selling them, which could mean it's using some generic cheap GPS and they are using the U-Blox name as a reputable brand to sell them.  It will no doubt work, and be accurate enough, but long term reliability could be an issue - how will you know if it stops or throws out some odd data?

For such a "fit and forget" type of installation I would err on the side of caution and see what was available from an EU/US source with a manual not riddled with typos.