Many transponders in close proximity

"jettester" wrote in message
oups.com...
#1. Transponders would not solve the mid air problem unless you were
the only one in close proximity to the attacking aircraft. Typically,

TCAS can't factor multiple threats?!? Even the lowly Zaon MRX can.

they set MTI (moving target indicator) to above 60K or higher
(especially if near a large amount of highway ground traffic), so once
you start thermalling they lose you unless you are given a discrete
squawk other than 1200 (for non participating VFR Traffic)

TCAS filtering out "highway ground traffic" ...squawking 1200?

The biggest benefit of transponder is not that people on the ground will see
you -- after all, they are not the ones that are going to hit you. My
transponder is on not as much for the ATC, but for the TCAS/TPAS flying out
there.
--
Yuliy

Yuliy Gerchikov wrote:
"jettester" wrote in message
oups.com...
#1. Transponders would not solve the mid air problem unless you were
the only one in close proximity to the attacking aircraft. Typically,

TCAS can't factor multiple threats?!? Even the lowly Zaon MRX can.

they set MTI (moving target indicator) to above 60K or higher
(especially if near a large amount of highway ground traffic), so once
you start thermalling they lose you unless you are given a discrete
squawk other than 1200 (for non participating VFR Traffic)

TCAS filtering out "highway ground traffic" ...squawking 1200?

I think he's talking about ground radar. TCAS gives not a hoot about
mode A codes.

Yuliy Gerchikov wrote:
"jettester" wrote in message
oups.com...
#1. Transponders would not solve the mid air problem unless you were
the only one in close proximity to the attacking aircraft. Typically,

TCAS can't factor multiple threats?!? Even the lowly Zaon MRX can.

they set MTI (moving target indicator) to above 60K or higher
(especially if near a large amount of highway ground traffic), so once
you start thermalling they lose you unless you are given a discrete
squawk other than 1200 (for non participating VFR Traffic)

TCAS filtering out "highway ground traffic" ...squawking 1200?

The biggest benefit of transponder is not that people on the ground will see
you -- after all, they are not the ones that are going to hit you. My
transponder is on not as much for the ATC, but for the TCAS/TPAS flying out
there.
--
Yuliy

This is why I love these websites....
The Zaeon MRX Unit is intriguing for several reasons...
1. Its relatively cheap $500
2. It uses 2 self contained batteries (from 5.8 to 7 hrs duration)
3. The ATC radar interogates the other aircraft and the MRX just
listens to the replies
4. You don't have to have a transponder or Mode C
5. Its small and lightweight
6. It gives relative altitude from your altitude (built in digital
altimeter)
7. I don't mess ATC up if I'm not talking or participating with
them.

Draw backs are... it still only helps with finding other aircraft with
transponders and mode C.

I'm glad to hear that at places like Minden and Arizona you guys are
using a discrete code with ATC's blessing. It still would mean you are
talking with the ATC controllers on their freq.
.... Incidentally, we (USAF) did tests with fibreglas gliders to see if
we could "see" them with ATC radars.. you typically could not unless
they increased their power above the rated power they were authorized
at the time... yet, if we put wadded up tin foil (Reynolds Aluminum
wrap) in the wings, they showed up like gang busters.

Jettester (UP)

jettester wrote:

I'm glad to hear that at places like Minden and Arizona you guys are
using a discrete code with ATC's blessing. It still would mean you are
talking with the ATC controllers on their freq.

No talking for code 0440 is required at Minden, anymore than is required
for code 1200. You just punch it in and use it while VFR.

... Incidentally, we (USAF) did tests with fibreglas gliders to see if
we could "see" them with ATC radars.. you typically could not unless
they increased their power above the rated power they were authorized
at the time... yet, if we put wadded up tin foil (Reynolds Aluminum
wrap) in the wings, they showed up like gang busters.

Seattle center and the local approaches don't seem to have problems
seeing our gliders, especially if we announce our prescence. Perhaps
your tests predate the newer radars?

--
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

www.motorglider.org - Download "A Guide to Self-launching Sailplane
Operation"

Eric Greenwell wrote:
jettester wrote:

I'm glad to hear that at places like Minden and Arizona you guys are
using a discrete code with ATC's blessing. It still would mean you are
talking with the ATC controllers on their freq.

No talking for code 0440 is required at Minden, anymore than is required
for code 1200. You just punch it in and use it while VFR.

... Incidentally, we (USAF) did tests with fibreglas gliders to see if
we could "see" them with ATC radars.. you typically could not unless
they increased their power above the rated power they were authorized
at the time... yet, if we put wadded up tin foil (Reynolds Aluminum
wrap) in the wings, they showed up like gang busters.

Seattle center and the local approaches don't seem to have problems
seeing our gliders, especially if we announce our prescence. Perhaps
your tests predate the newer radars?

--
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

www.motorglider.org - Download "A Guide to Self-launching Sailplane
Operation"

I did a Electronics Counter Measures test in the late 1980's against
their (Seattle's) radar, and their's is the newest in the country and
the most capable.

Jettester (UP)

jettester wrote:
... Incidentally, we (USAF) did tests with fibreglas gliders to see if
we could "see" them with ATC radars.. you typically could not unless
they increased their power above the rated power they were authorized
at the time... yet, if we put wadded up tin foil (Reynolds Aluminum
wrap) in the wings, they showed up like gang busters.


Tucson approach had no problem seeing my ASW-19B, and vectoring airline
traffic round me as a climbed. I was not squawking anything except
"please let me stay here long enough to get enough altitude to get
home".


Andy

Andy wrote:
Tucson approach had no problem seeing my ASW-19B, and vectoring airline
traffic round me as a climbed. I was not squawking anything except
"please let me stay here long enough to get enough altitude to get
home".

They could see a Kestrel back in the mid 1970's at 30 miles or so if I
recall correctly. One of the Tcson Soaring Club members did some
testing with them.

-Tom

I do not know what radar band ATC uses, but couldn't one suspend a
metalic reflector like sailboats use to provide a radar return? Of
course, space would be consideration depending on the glider model (see
http://www.tri-lens.com/trilensweb12002002.htm)

... Incidentally, we (USAF) did tests with fibreglas gliders to see if
we could "see" them with ATC radars.. you typically could not unless
they increased their power above the rated power they were authorized
at the time... yet, if we put wadded up tin foil (Reynolds Aluminum
wrap) in the wings, they showed up like gang busters.

Jettester (UP)

That doesn't provide altitude data, and the radar return would potentially
be filtered out as ground traffic due to the slow speeds involved.

Mike Schumann

"James D'Andrea" wrote in message
ps.com...
I do not know what radar band ATC uses, but couldn't one suspend a
metalic reflector like sailboats use to provide a radar return? Of
course, space would be consideration depending on the glider model (see
http://www.tri-lens.com/trilensweb12002002.htm)

... Incidentally, we (USAF) did tests with fibreglas gliders to see if
we could "see" them with ATC radars.. you typically could not unless
they increased their power above the rated power they were authorized
at the time... yet, if we put wadded up tin foil (Reynolds Aluminum
wrap) in the wings, they showed up like gang busters.

Jettester (UP)

jettester wrote:
\
#4. MODE S transponders have a discrete ID code embedded in the
transponder that is supposed to be set to your aircraft registry ID
(look on the FAA website for your aircraft registry information and you
will find that ID for your aircraft). Mode S talks to other mode S
equipped transponders, and is typically used to provide TCAS (Traffic
Collision Avoidance System) information to issue the advisories to each
aircraft. If you have this feature, and were to pullup rapidly with
another mode S aircraft overhead, it could set off his traffic warning
system.

A mode S transponder is not required for an aircraft to be detected
by TCAS. The conflicting traffic only needs mode C for the TCAS
to give an RA. The only advantage mode S gives is that if you have
TWO TCAS equipped aircraft, they use the mode S datalink to coordinate
a resolution (one climbs the other descends).