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Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Fri Oct 10, 2014 9:21 pm
by CTLSi
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Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Fri Oct 10, 2014 9:36 pm
by SportPilot
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Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Sat Oct 11, 2014 7:52 am
by MrMorden
designrs wrote:Oh yes. Everybody wants it. I can't believe it's not out now.
Put an antenna on the Stratus and ping it out!
The GPS position source requirement is what makes this stumble. It would by pretty easy to do, but would not be 2020 compliant without the expensive TSO position source. And if it's like GPS, no portable ADS-B portable will get certification, which means additional expense for installation.

Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Sat Oct 11, 2014 8:08 am
by FastEddieB
designrs wrote:Oh yes. Everybody wants it.
Well, not everybody.

I, for one, enjoy having less stuff to buy, install and futz with - not more!

Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 10:11 am
by designrs
The recent mid-air plane crash Yerington / Carson, Nevada made me think about how much safer we would be if everyone had ADS-B In/Out. In this day and age of electronics it's so unnecessary for something tragic like that to happen.

Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 10:29 am
by CTLSi
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Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 10:40 am
by MrMorden
CTLSi wrote: ADS-B coverage present. My ADS-B is in full use when I fly over that area given how busy the area is for GA aircraft. But I only see other aircraft that are also equipped with ADS-B Out.
If you have ADS-B out, and there is ground station coverage, you should see everybody with a Mode-C transponder, not just other ADS-B users.

Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 10:44 am
by drseti
MrMorden wrote:If you have ADS-B out, and there is ground station coverage,
As Shakespeare wrote, "Aye, there's the rub." Not sure there was ground station coverage in the accident area. That's why a totally self-contained, active system (google "BiDCAS") makes so much more sense than ADS-B. But this is a dead issue - FAA made up its mind decades ago to keep ground radars (and their ATC empire) in the loop.

Edit: I see that Google doesn't link to all those old EAA articles from the 1980s. So, start here instead:

http://microcomm.net/research/bidcas.pdf

Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 10:54 am
by dstclair
Coverage at 1K is not usually good in areas outside of major metros even in areas with coverage.

Nevada has a few holes in the coverage as per the FAA chart as well.

Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 10:59 am
by designrs
Even the more reason to have ADS-B In/Out.
There is coverage everywhere if both planes are equipped In/Out.

Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 11:03 am
by drseti
Richard, that's only true if everybody's equipment is turned on all the time, and working flawlessly, and never fails. Remember, we're talking electronics here - I'm sure your PC has never locked up, right? :twisted:

Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 11:17 am
by MrMorden
drseti wrote:Richard, that's only true if everybody's equipment is turned on all the time, and working flawlessly, and never fails. Remember, we're talking electronics here - I'm sure your PC has never locked up, right? :twisted:
Though isn't ADS-B out going to be like a transponder: "must be on if equipped"?

Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 12:27 pm
by SportPilot
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Re: ADS-B Reflections - (a confession and a suggestion)

Posted: Mon Oct 13, 2014 1:21 pm
by drseti
MrMorden wrote:Though isn't ADS-B out going to be like a transponder: "must be on if equipped"?
Yes, but "equipped" doesn't always mean "operational".

In the old days, transponders produced their 1090 MHz signals with a ceramic planar triode, a vacuum tube that had about a 1000 hour lifetime. But, MTBF could vary unpredictably. That meant that, during any one-hour flight, there was a 0.1% probability of transponder failure. And, when (not "if", but "when") your transponder failed, you had absolutely no way of knowing that you just became invisible.

OK, so now with solid-state transponders, the MTBF is longer. But there's still a non-zero probability of transponder failure on any flight, and when that happens, nobody can see you. Same goes for ADS-B Out. This is why ADS-B will never be a replacement for see-and-avoid.

The point is, no matter how well you equip and maintain your aircraft, you're vulnerable to somebody else's equipment failure. That was the whole point of BiDCAS, when EAA supported it in 1987. With it, the other aircraft (or non-transponder-equipped seagull) could be seen by its radar reflective surface. You would only have been vulnerable to collision with the Lockheed F117 Stealth Fighter. :wink:

Of course, the FAA's Chief Scientist opposed this technology because it took controllers out of the loop, puting all the power in the hands of the pilot. So, they mandated TCAS (and now NexRad) instead.