On Jan 19, 9:27*am, Martin Gregorie
wrote:
On Mon, 19 Jan 2009 08:25:29 -0800, Darryl Ramm wrote:
As for wanting a Mode-S transponder with "TCAS" display. You can get
this today. In the USA PCAS units like the Zaon MRX are popular and use
very low power and relatively low cost (~$500). They provide an alert
but no RA or direction information.

I, for one, appreciate that Mode-S plus PCAS will do the full electronic
see-and-be-seen bit, but its a two box solution with any instruments I've
seen advertised.

Some of us just don't have the panel space for that. I fly a Libelle and
currently have all panel holes bar one full. The blanking plate in the
remaining one supports my GPS on a stalk. Nonetheless, I think I can get
a 57mm transponder in alongside the stalk mount, but that will certainly
need a replacement panel chassis and may need my 80mm altimeter to be
replaced with a 57mm unit.

That exercise leaves me with the transponder, but where can I put the
PCAS? In a Libelle there's no way it can be put on top of the panel and
there is little if any available space along the cockpit sides. This is
why I, for one, really need a single, 57mm instrument combines both
transponder and PCAS and is low power enough to run off a glider battery.

If such an instruments exists I'd love to know the details.

Derek is right about our airspace: I've never met anything other than *
other gliders, GA aircraft, a few helicopters, the odd hang glider/
parascender and one or two military aircraft when I've been on an xc
task. The usual opposition to a glider on an xc task is GA pilots. I bet
they don't carry PCAS/TCAS and I'm not under ATC control. Under these
conditions the introduction of transponders does not reduce my changes of
a collision unless I have PCAS onboard. Hence my interest in the combined
instrument. *

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

I know nothing about UK airspace (besides being stuck in it for far
too much time as a passenger holding over Heathrow), but it sounds
like the existing separation of airliner and jets in UK airspace is a
key point you folks should be arguing.

And again only one of the transponder aircraft needs to be talking to
ATC/radar facilities or have PCAS or higher. I don't know PCAS (and
higher-end systems) adoption in low-end GA aircraft in the UK, but in
the USA it seems pretty high (purely an anecdotal impression). I've
asked before but could not get adoption numbers for the USA.

Companies who make panel mounted transponders usually do so for the
larger GA market and they have to coexist with all sorts of PCAS,
active systems (like the Avidyne) and full on TCAS. I would not hold
my breath for a transponder with integrated PCAS. But maybe now
manufacturers will be making them mostly for UAVs and those UAVs could
do with integrated PCAS :-(

In the Libelle you might be able to make up a mount for a Zaon MRX
under the opaque areas of the front of the canopy, it might be canted
over parallel to the surface, and use an antenna mounted on suction
cups on the canopy. Obviously paying attention to canopy jettison
issues. I'd be kind of surprised it is impossible, but not saying its
going to be trivial.

Darryl