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View Full Version : Old tecnology and inertia - transponders


February 25th 07, 06:54 PM
It is snowing outside and privately I have been corresponding about
the successful installation of a transponder in my SparrowHawk and
transponders in general and thought this might be some interest to
many of you .
Dave

Hi Jim
There are many systems that we would agree with few exceptions are
poor
and could be replaced with today's technology resulting in much better
accuracy, safety and cost. Sometimes the technology switchover is fast
and relatively painless. Lets consider the use of GPS for aircraft
applications. There are really 2 uses for GPS. The first is to know
your position, direction, height and speed and the second for all
other near aircraft and ATC to have that same information. The first
is
easy to solve since it is on an individual basis and does not affect
anyone else. The second is much more problematical in that the
communication and protocols have to be universal the whole world over.
So what has happened? Almost everyone uses a GPS in their flying
machines and the old techniques such as VORs are out. My new Jabiru
only has a GPS for navigation. The new technology is infinitely better
in all respects to the old technologies. Now lets look at transponder
technology which is 50 years old. It works and it actually works
better
than one would suspect since distance is based on signal strength
only and there is no one position on an aircraft for mounting the
antenna. If it is mounted on a metal aircraft in a prominent position
I am sure the efficiency is greater than say on my DG where the
antenna is mounted inside the cockpit above the instrument panel.
Regardless transponders work fairly well overall. So why change?
I think there are several reasons. Much more and more accurate
information can be communicated such as position to about 20
feet, altitude to 100 feet, heading, speed, climb or sink rate and
the ability of an inboard computer to suggest action in the case
of a potential collision. This would negate all the silly little add
ons
such as TCAS etc. So why hasn't it happened? Because it is
a huge project to get all the countries in the world to approve
a new system and to implement it.
Lets as engineers consider what the hardware could look like
My $300 Navman has a GPS and operates using Microsoft's
2003 PDA operating system. Without doubt a program could
be written simply and efficiently to achieve everything that I
have been discussing except for the transmitter but that is a
piece of cake! The total size would bt that of a Garmin 396
and the manufacturing costs no more (and I am being generous)
than $500. Sounds easy and so it is. When will it be available
and FAA approved? Your guess is as good as mine.
Dave

kirk.stant
February 26th 07, 02:25 PM
It's been done, and is in widespread use by gliders (just not in the
US or Canada, thanks to lawyers). It's called FLARM. Won't keep that
Airbus from hitting you, however...

One of the problems with transponders is that they don't tell you
where other traffic is - they just tell others where you are. So you
still need TCAS or TPAS capablility if you like being actively
involved in avoiding a collision.

Bottom line - make yourself visible (xponder helps), know where the
threat is likely to be (TPAS helps) and look out the window (clean
canopy helps).

Kirk
66

Robert van de Sandt
February 26th 07, 02:32 PM
kirk.stant schrieb:
> It's been done, and is in widespread use by gliders (just not in the
> US or Canada, thanks to lawyers). It's called FLARM. Won't keep that
> Airbus from hitting you, however...

Really good system. For everybody who does not know.
http://www.flarm.com/index_en.html

Robert

Marc Ramsey
February 26th 07, 06:49 PM
kirk.stant wrote:
> It's been done, and is in widespread use by gliders (just not in the
> US or Canada, thanks to lawyers). It's called FLARM. Won't keep that
> Airbus from hitting you, however...

I wouldn't blame the lawyers (just some skewed perceptions), if they
were really that bad, we would no longer be getting any gliders
delivered to this country.

FLARM may make sense in Europe, but I don't think it makes sense in the
US, since the critical collision hazard is non-glider traffic. ADS-B
(essentially FLARM on steroids) is supposed to be the long term
solution, but I've been told the radar guys in the FAA are doing what
they can to slow down deployment...

Marc

Ramy
February 26th 07, 07:17 PM
On Feb 25, 10:54 am, " >
wrote:
<snip>
> than one would suspect since distance is based on signal strength
> only and there is no one position on an aircraft for mounting the
> antenna. If it is mounted on a metal aircraft in a prominent position
> I am sure the efficiency is greater than say on my DG where the
> antenna is mounted inside the cockpit above the instrument panel.

My understanding is that distance is calculated based on timing of the
reply and not signal strength, and as such, is pretty accurate.

Ramy

kirk.stant
February 27th 07, 01:59 PM
> I wouldn't blame the lawyers (just some skewed perceptions), if they
> were really that bad, we would no longer be getting any gliders
> delivered to this country.

As I understand it, FLARM is specifically prohibited from use in the
US and Canada for liability reasons. To me, that means lawyers.
There may be frequency issues also, or I just may be full of it!

I tend to think gliders are such a small part of aviation that lawyers
haven't yet found out about all those plastic "EXPERIMENTAL RACING"
death traps floating around our skies piloted by 14 year olds, waiting
for the wind to stop so they could crash into schools and blow up.

> FLARM may make sense in Europe, but I don't think it makes sense in the
> US, since the critical collision hazard is non-glider traffic. ADS-B
> (essentially FLARM on steroids) is supposed to be the long term
> solution, but I've been told the radar guys in the FAA are doing what
> they can to slow down deployment...

I totally agree.

Cheers,

Kirk

Jack[_1_]
February 27th 07, 06:01 PM
kirk.stant wrote:

> As I understand it, FLARM is specifically prohibited from use in the
> US and Canada for liability reasons. To me, that means lawyers.
> There may be frequency issues also, or I just may be full of it!


Kirk, it's not the lawyers -- it's the people who hire the them.

Let's sue the *******s!


Jack

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