ADSB visibility with non certified GPS

Jumping into the middle of this - what's the real reason to ignore an
ADS-B Out aircraft simply because the GPS source is "crappy"?Â* So what
if the position is off by 100 feet or so?Â* My PowerFLARM routinely
reports targets at 200 feet or more altitude difference, e.g., I may get
a report of a target 100 feet high and spot him a hundred feet or so
lower than I am.

It just seems ridiculous to ignore another aircraft which might be on a
collision course simply because his altitude or position may be reported
as a couple of hundred feet different from where he is. That's what
looking outside is for.Â* Following the same logic, of what use is a
non-TSO compliant GPS in an experimental aircraft if it will be ignored
by other aircraft?

Inquiring minds and all...Â* BTW, I plan on installing a TN70 to mate
with my TT22 in my certificated glider.

On 9/21/2017 7:41 PM, Darryl Ramm wrote:
On Thursday, September 21, 2017 at 6:20:54 PM UTC-7, wrote:
What hasn't been discussed is how often non-approved ADSB out sources are actually being ignored.
Ah I think we've been over what matters here many times, but it is a mess.

100% of certified ADS-B in systems will ignore the ADS-B data from 100% of ADS-B Out systems that use a COTS/non-complaint GPS source 100% of the time.

So airliners, fast jets, regional jets, etc. which if they have ADS-B In at all will be a certified In system, definitely won't see some scabby ADS-B Out install using a COTS GPS source. Since many of those aircraft today have TCAS II they will be see the transponder via TCAS and be able to issue TCAS TA and RA fro that target. However the gap in the middle is with many high-end GA aircraft that have certified ADS-B In but no TCAS, they won't see a crappy COTS driven ADS-B Out. But at the low-end GA market non-certified portable ADS-B In systems will see those COTS powered targets. That is kinda brain dead but it's how it is and easy to work around.. don't use a COTS GPS source....

With the relatively low price of theTN72, if owners want to equip an experimental glider with ADS-B Out there is no excuse anymore for using a COTS GPS source. I really don't want to get into how many GA aircraft might or might not be affected, just do it properly and install a TN72 or TN70 system. COTS GPS is just the wrong thing.


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Dan, 5J