This weekend the friend of mine who's helped with my filter/prioritization box that we built took the time to hook up his Echo UAT with the antenna outdoor on top of his building. He also ran an antenna for a stratux near it too. He observed much better reception with the stratux, but that may be due to the Echo intentionally being attenuated slightly to deal with the very nearby transponder transmitting. He also observed the serial output from the Echo and again confirmed that at least on the rev of firmware on the uAvionix site, the traffic does not come out prioritized by proximity. I heard that the Dynon unit may have updated firmware that does do this, so that is a positive in that perhaps down the road we will see it.
One other observation is that some of the GDL90 data on targets is not good data that is being put out of the echo, but I don't know the details on this. It does not appear that they do any coasting of traffic on the echo, either. My EFIS, for one, does not coast. I know that AFS has been able to do a lot of things on the EFIS that would mitigate some of these issues, but while that is a great thing, some things really should be done on the UAT. One big for instance (that the Echo UAT does indeed do, but my iLevil did NOT do last year, is filter out ownship ICAO code). Basically, it should be expected of the UAT to put out good complete data on the intruder targets, prioritized by proximity, filtered for ownship ICAO, bound to certain altitude limitations to prevent serial link congestion, coasting of the targets so that if they do blink out, their heading, speed, climb/descent rate are tracked and they don't immediately blink out, and also de-ghosted. There is a TIS-B Track file ID (you can read about it in the GDL 90 spec in section 3.5.1.2) that gets sent by the GBT with an ICAO code-ish looking code for primary targets, that may be sent to your location if the FAA picks you up and doesn't correlate your ownship ICAO with that primary target. That will cause a traffic alert on yourself.
I've heard that there may be issues with the number of GBT's the echo sees, that causes some glitches too. Making the huge assumption that the hardware has the power to do the proper traffic processing, I would think that all of the above filtering issues should be relatively easily solved. The one I'd worry about more is any issues related to GBT reception and glitches. Hopefully the RF section of the unit is able to deal with all of this.
Time will tell how well the internal filtering capabilities work out, and from Shane's reply it's apparent that they're working on it. The only negative about a good coasting configuration is that it may mask some of the glitchy traffic issues, but then again, one of the positives of a good coasting config is that it can mask some of the glitchy traffic issues.
My Chelton EFIS that caused me to learn more than I originally intended to on this, can be fed either a GDL90 stream, or a serialized version of TCAS. I wanted the TCAS type data for technical reasons (it allows me to have satellite wx instead of FIS-B wx) but it required a bit of work to do conversion of GDL90 data. The upside of the project is that we were able to basically completely or very nearly so, fix all of the above issues for my interface. The system works ok for me once that processing has been done.
I have a few friends that I talked into buying Echos though, and so we're now starting to try to do the GDL90 in <> GDL90 out box that will do the same thing. We build a table of all nearby targets, each new one that shows up is matched to either fit in that table in order of proximity, or discarded if it's further away. The table size can be adjusted based on the output interface speed required, to ensure that you will never overdrive what the bandwidth of your RS232 setting can deliver. It'll be interesting to see if we can get it all done.
Based on today's situation, I'd recommend that there's enough we've learned that I'd hold off on a UAT purchase for the time being. Give them time to see how this settles out. If it isn't something that's able to be improved, I'd really recommend that people look for a more robust product for themselves. The only issue is price. At this point I've spent roughly $2800-3000 per plane by buying a NavWorX system, and then tossing it for an Echo. At some point that money would have been better spent on the initial purchase. At least those of you who are still yet to equip have the ability to save yourself the hassle of buying something that doesn't need to get replaced soon. I'd say by Sun-n-Fun or for sure by OSH, if this whole thing isn't resolved, you'd be able to at least eliminate one solution from your list. If it is resolved, it could well be the best price in ADS-B for your plane.
On a side note, I haven't really had a chance to check out how good the weather reception is on the Echo. Does anyone have any reports on how that works for them?