Shorrick_Mk2 wrote:
Well you better tell L3 then, as the LGT-9000+ GA transponder and TAS works with the same bits and bobs used on jet installations, and in both cases seems to effectively work with offending mode S transponders up to 50 miles out…
I think what Peter means is that it won’t work on mode S alone (unless it is full compliance ADS-B). These systems normally use mode A/C too determine range and bearing (or ADS-B), not mode S only. As one normally doesn’t have mode S without mode A/C this isn’t a problem, and the A/C mode is used for detection, and merged with ADS-B if available.
So you are right, saying that in practice it will work with all transponders.
AIUI, with say a TAS605 box, a target which is A+S will show the range and bearing but not relative altitude.
And even with the (vapourware) ADS-B module installed in the TAS605, that will be the same.
And if radiating SIL=0 ADS-B (like all the cheap ADS-B OUT boxes do) that will still be the same.
Only Mode C (regardless of S) targets show up properly on the TAS605.
Only SIL=1+ ADS-B targets will show up properly on the TAS605 which has the (vapourware) ADS-B module.
So basically Mode S doesn’t change anything as regards useful visibility of the target, since no additional information (of use) is radiated.
What might be useful would be radiating the altitude on Mode S even if Mode C is turned off 
and having the TAS605 use that, but I don’t think that quite happens
Which precise bits of the above are incorrect, and why?
Peter wrote:
altitude on Mode S even if Mode C
Altitude is included in both. Peter wrote:
So basically Mode S doesn’t change anything as regards useful visibility of the target, since no additional information (of use) is radiated.
Not to you, but it does for ATC and it does for all those people with Power Flarm, Garrecht TRX, Pilot Aware and others. So yes it should be promoted for have transponder with mode ACS and include ADS-B on own iniative.
With your TAS system, you don’t loose anything. All those people without at TAS system but with others systems as mentioned earlier will benefit.
Wading through the innumerable threads on enhanced conspicuity, here and elsewhere, reminds me that the simplest thing that I could do is to hook up my existing certified GPS and mode S transponder for ADS-B. However, that route requiring only a simple cable and some configuration is frustrated by paperwork requirements. In an Annex 2 aircraft no problem, but here not so simple!
Does anyone here know if any existing STC’s cover this, or if the official position is likely to follow the non-certified route? PA28, non-W 430, TT31.
Peter: apologies if this is covered already, but could not find it. Thanks.
After some thought I moved Aveling’s post to this existing ADS-B thread as it does deal mainly with certified ADS-B OUT options.
I have no idea what the legal ADS-B OUT route is for a GNS430 and a TT31 transponder – if there is one.
Aveling wrote:
Does anyone here know if any existing STC’s cover this, or if the official position is likely to follow the non-certified route? PA28, non-W 430, TT31.
AFAIK: In order to generate the GPS position for ADS-B, you need a WAAS capable, certified GPS source – this means the GNS430 does not fulfil the requirements, you’d need to replace it with a GNS430w. I’m in a similar position, have a GTX330-ES transponder but no certified source (both GNS430s are the non WAAS type).
My options are limited because something like a GPS20A is only for experimental / home built aircraft. With the TT31 already installed, you could actually purchase a TN70 from Trig and have that installed. Job done. The only problem – price. Upwards of 2k….
However unlike the Foreflight or Garmin offerings. Trig are now offering a cheaper alternative, the TN72 – this will be around quarter of the cost…….
I too think the GNS430 won’t do, but what about the SIL=0 etc discussion above? I have not managed to get my head around the current options for Europe but there is much discussion around “low cost” routes to ADS-B OUT which radiate SIL=0.
What seems clear is that nothing other than SIL=3 will ever show on any certified TAS system – see earlier posts around here. All of them are American products and there SIL=0 is AIUI no longer allowed. Whether this matters to you depends on whether you want to be visible to the fastest GA traffic (basically IFR SEPs and above) which mostly uses certified TAS. Personally if I was installing ADS-B OUT I would not radiate anything below SIL=3 because I want to be visible to this fast traffic, and the other traffic (flying with various velcroed bits around the cockpit) is mostly avoided by flying above 2000ft 
And obviously you can in principle have very low cost ADS-B IN (in some portable form) because you aren’t radiating anything; after all, one can do ADS-B IN with a £10 USB TV receiver dongle
I think @NCYankee is the expert here on this stuff. This may be relevant to others
EASA Standard Change CS-SC002b
INSTALLATION OF MODE S ELEMENTARY SURVEILLANCE EQUIPMENT :
This SC does not satisfy requirements set by CS-ACNS Subpart D Section 4 1090 MHz Extended Squitter (ES) ADS-B Out installations compliant to Section 4 of CS-ACNS or nor AMC 20-24.
However, the voluntary transmission of additional ADS-B data (e.g. GPS position and velocity) can be accepted when the position and velocity quality indicators report the lowest quality, the equipment manufacturer has stated compatibility with the directly connected GNSS source, and the transponder is not authorised in accordance with ETSO-C166b or equivalent.
So according CS-STAN I would run a TT31 with a V2 firmware (V3 is ETSO-C166b compliant so not approved under CS-STAN) and connect it to the GNS430.
Which ADS-B IN products would see the above emissions, and display relative traffic position?
Guillaume wrote:
So according CS-STAN I would run a TT31 with a V2 firmware (V3 is ETSO-C166b compliant so not approved under CS-STAN) and connect it to the GNS430.
Why would you connect it to a GNS430? It would not provide you with ADS-B because the GPS Source needs WAAS capabilities.
Peter wrote:
but there is much discussion around “low cost” routes to ADS-B OUT which radiate SIL=0.
According to Trig, their TN72 will provide a ‘non zero’ SIL – whether that’s 1, 2 or 3 is unclear. Either way, it should be a cheap and effective way to provide ADS-B out compliance….
edited to add: I have just heard in a YouTube video that the TN72 is uncertified hence just for Experimental or Home Built aircraft… Yet another perfect example of how certification impacts safety in GA – if the TN72 can provide a ‘non zero’ SIL for less than $400, why is a certified unit which probably provides the same performance need to be sold for $2k plus…..
Peter wrote:
What seems clear is that nothing other than SIL=3 will ever show on any certified TAS systemMy take on that is slightly different. I believe that both TAS / TCAS systems will show the target but, due to the potential for incorrect position data, TCAS systems will not provide RAs
