Many transponders in close proximity [Archive]

August 31st 06, 04:34 PM

jettester

August 31st 06, 10:29 PM

5Z wrote:
> With all this discussion going on now, maybe someone with some
> knowledge or experience could enlighten us on the consequences of 10 or
> more sailplanes in a tight gaglge all squawking the same info. Will
> ATC see them all? Or will interference and/or filtering software at
> ATC make some or all of them invisible?
>
> Will TCAS be able to make sense of all these close together
> transponders?
>
> Remember, the typical application of the transponder is to separate
> traffic, so it is very unusual to have two (in our case 5, 10 or even
> 40) or more within 1,000' of each other. Can furrent technology deal
> with that, or will equipping all sailplanes create more problems than
> it solves?
>
> Thanks
>
> -Tom

Tom;
I am a FAA Test Pilot who is authorized to test Transponders in new
aircraft... I do this for a living. I also was qualified as a Hawker
800XP test pilot.

Bottom Line - Transponders are NOT the answer! Try putting one of
these new LED Strobe Lights on the top of your Fin instead.

#1. Transponders would not solve the mid air problem unless you were
the only one in close proximity to the attacking aircraft. Typically,
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)

#2. If multiple gliders (or aircraft) are in the vicinity all
squawking 1200, ATC could not tell one from the other. Mode C (if you
have it) reports altitude, yet if the climb or descent rate is large
(let's say greater than 1500fpm) their equipment typically faults you
off the scope and does not report your altitude. Once again unless you
are given a discrete squawk other than 1200 (VFR traffic).

#3. If multiple gliders (or other aircraft) are in the same proximity
on closing trajectories, the ATC system will issue warnings to the
controller, that he must issue to the offending aircraft, to try to
prevent them from colliding.... Unless you are in direct communication
with ATC, they will probably get extremely miffed (read.. ask you to
call them when you land, and they will probably find you!!) because
they are spending more time trying to cancel these warnings to control
other "participating" aircraft.

#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.

#5. I have flown in wave with a transponder equipped glider, yet I was
talking with ATC and had clearance into the window. Always, conditions
were VMC, even though operating in Class A airspace under an IFR Flight
Plan.

#6. Transponders are expensive... DO NOT solve the "see and avoid"
problem.. can potentially really mess ATC up if you are not in direct
contact with them.. and in the case of the Hawker midair..... would not
have prevented the collision.

Jettester (UP)

Al[_1_]

August 31st 06, 10:50 PM

"jettester" > wrote in message
oups.com...
> 5Z wrote:
>> With all this discussion going on now, maybe someone with some
>> knowledge or experience could enlighten us on the consequences of 10 or
>> more sailplanes in a tight gaglge all squawking the same info. Will
>> ATC see them all? Or will interference and/or filtering software at
>> ATC make some or all of them invisible?
>>
>> Will TCAS be able to make sense of all these close together
>> transponders?
>>
>> Remember, the typical application of the transponder is to separate
>> traffic, so it is very unusual to have two (in our case 5, 10 or even
>> 40) or more within 1,000' of each other. Can furrent technology deal
>> with that, or will equipping all sailplanes create more problems than
>> it solves?
>>
>> Thanks
>>
>> -Tom
>
> Tom;
> I am a FAA Test Pilot who is authorized to test Transponders in new
> aircraft... I do this for a living. I also was qualified as a Hawker
> 800XP test pilot.
>
> Bottom Line - Transponders are NOT the answer! Try putting one of
> these new LED Strobe Lights on the top of your Fin instead.
>
> #1. Transponders would not solve the mid air problem unless you were
> the only one in close proximity to the attacking aircraft. Typically,
> 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)
>
> #2. If multiple gliders (or aircraft) are in the vicinity all
> squawking 1200, ATC could not tell one from the other. Mode C (if you
> have it) reports altitude, yet if the climb or descent rate is large
> (let's say greater than 1500fpm) their equipment typically faults you
> off the scope and does not report your altitude. Once again unless you
> are given a discrete squawk other than 1200 (VFR traffic).
>
> #3. If multiple gliders (or other aircraft) are in the same proximity
> on closing trajectories, the ATC system will issue warnings to the
> controller, that he must issue to the offending aircraft, to try to
> prevent them from colliding.... Unless you are in direct communication
> with ATC, they will probably get extremely miffed (read.. ask you to
> call them when you land, and they will probably find you!!) because
> they are spending more time trying to cancel these warnings to control
> other "participating" aircraft.
>
> #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.
>
> #5. I have flown in wave with a transponder equipped glider, yet I was
> talking with ATC and had clearance into the window. Always, conditions
> were VMC, even though operating in Class A airspace under an IFR Flight
> Plan.
>
> #6. Transponders are expensive... DO NOT solve the "see and avoid"
> problem.. can potentially really mess ATC up if you are not in direct
> contact with them.. and in the case of the Hawker midair..... would not
> have prevented the collision.
>
> Jettester (UP)
>

Thank you.

Al G

Mike the Strike

August 31st 06, 11:01 PM

Great info. It seems obvious that gliders should have a code different
from the generic 1200 so they can be tracked more efficiently and
separated from other general aviation traffic, but I guess there are
only a handful of places in the US where this is the case. Around the
heavily-trafficked Sky Harbor in Phoenix we mix it with dozens of GA
aircraft on 1200, while in the lightly occupied space further south,
the Tucson Soaring Club have been allocated 0400. Perhaps it's time
for some uniform codes?

Mike

Al wrote:
> "jettester" > wrote in message
> oups.com...
> > 5Z wrote:
> >> With all this discussion going on now, maybe someone with some
> >> knowledge or experience could enlighten us on the consequences of 10 or
> >> more sailplanes in a tight gaglge all squawking the same info. Will
> >> ATC see them all? Or will interference and/or filtering software at
> >> ATC make some or all of them invisible?
> >>
> >> Will TCAS be able to make sense of all these close together
> >> transponders?
> >>
> >> Remember, the typical application of the transponder is to separate
> >> traffic, so it is very unusual to have two (in our case 5, 10 or even
> >> 40) or more within 1,000' of each other. Can furrent technology deal
> >> with that, or will equipping all sailplanes create more problems than
> >> it solves?
> >>
> >> Thanks
> >>
> >> -Tom
> >
> > Tom;
> > I am a FAA Test Pilot who is authorized to test Transponders in new
> > aircraft... I do this for a living. I also was qualified as a Hawker
> > 800XP test pilot.
> >
> > Bottom Line - Transponders are NOT the answer! Try putting one of
> > these new LED Strobe Lights on the top of your Fin instead.
> >
> > #1. Transponders would not solve the mid air problem unless you were
> > the only one in close proximity to the attacking aircraft. Typically,
> > 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)
> >
> > #2. If multiple gliders (or aircraft) are in the vicinity all
> > squawking 1200, ATC could not tell one from the other. Mode C (if you
> > have it) reports altitude, yet if the climb or descent rate is large
> > (let's say greater than 1500fpm) their equipment typically faults you
> > off the scope and does not report your altitude. Once again unless you
> > are given a discrete squawk other than 1200 (VFR traffic).
> >
> > #3. If multiple gliders (or other aircraft) are in the same proximity
> > on closing trajectories, the ATC system will issue warnings to the
> > controller, that he must issue to the offending aircraft, to try to
> > prevent them from colliding.... Unless you are in direct communication
> > with ATC, they will probably get extremely miffed (read.. ask you to
> > call them when you land, and they will probably find you!!) because
> > they are spending more time trying to cancel these warnings to control
> > other "participating" aircraft.
> >
> > #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.
> >
> > #5. I have flown in wave with a transponder equipped glider, yet I was
> > talking with ATC and had clearance into the window. Always, conditions
> > were VMC, even though operating in Class A airspace under an IFR Flight
> > Plan.
> >
> > #6. Transponders are expensive... DO NOT solve the "see and avoid"
> > problem.. can potentially really mess ATC up if you are not in direct
> > contact with them.. and in the case of the Hawker midair..... would not
> > have prevented the collision.
> >
> > Jettester (UP)
> >
>
> Thank you.
>
> Al G

September 1st 06, 12:07 AM

jettester wrote:
> Bottom Line - Transponders are NOT the answer! Try putting one of
> these new LED Strobe Lights on the top of your Fin instead.

EXCELLENT response! Sounds like the "transponder" option is to get a
Zaon MRX http://www.zaonflight.com/mrx.html It's better if I'm AWARE
of ALL the transponders nearby instead of just trying to become visible
to a few others with limited success.

Did a quick Google search for LED strobes and these are intriguing, but
looks like 1/3 to 1/2 amp drain, so even worse than transponder. But,
it may be possible to rig these to flash less frequently...

-Tom

HL Falbaum

September 1st 06, 01:01 AM

Thanks for the good info--
but I have a question--see #6 below---
If the ASG29 was squaking the discrete code used in the Minden area, would
the 800XP not have been alerted to the conflict?

--
Hartley Falbaum

"jettester" > wrote in message
oups.com...
>> -Tom
>
> Tom;
> I am a FAA Test Pilot who is authorized to test Transponders in new
> aircraft... I do this for a living. I also was qualified as a Hawker
> 800XP test pilot.
>
> Bottom Line - Transponders are NOT the answer! Try putting one of
> these new LED Strobe Lights on the top of your Fin instead.
>
>
> #6. Transponders are expensive... DO NOT solve the "see and avoid"
> problem.. can potentially really mess ATC up if you are not in direct
> contact with them.. and in the case of the Hawker midair..... would not
> have prevented the collision.
>
> Jettester (UP)
>

[email protected]

September 1st 06, 01:57 AM

Mike the Strike wrote:
> Great info. It seems obvious that gliders should have a code different
> from the generic 1200 so they can be tracked more efficiently and
> separated from other general aviation traffic, but I guess there are
> only a handful of places in the US where this is the case. Around the
> heavily-trafficked Sky Harbor in Phoenix we mix it with dozens of GA
> aircraft on 1200, while in the lightly occupied space further south,
> the Tucson Soaring Club have been allocated 0400. Perhaps it's time
> for some uniform codes?
>
> Mike

By common agreement between Nevada glider operations and Reno ATC,
local gliders all Sqwawk 0440. It works well and then routinely route
traffic around us.

Yuliy Gerchikov

September 1st 06, 04:15 AM

"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

Ron Natalie

September 1st 06, 04:59 PM

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).

Ron Natalie

September 1st 06, 05:00 PM

jettester

September 1st 06, 05:36 PM

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)

Ramy

September 1st 06, 07:34 PM

Ha? The Hawker TCAS would have not detect a mode c transponder on a
collision course at 16,000ft, even if in a gaggle and sqwawking 1200?
(we sqwawk 0440 at this area though).

Ramy

jettester wrote:
> 5Z wrote:
> > With all this discussion going on now, maybe someone with some
> > knowledge or experience could enlighten us on the consequences of 10 or
> > more sailplanes in a tight gaglge all squawking the same info. Will
> > ATC see them all? Or will interference and/or filtering software at
> > ATC make some or all of them invisible?
> >
> > Will TCAS be able to make sense of all these close together
> > transponders?
> >
> > Remember, the typical application of the transponder is to separate
> > traffic, so it is very unusual to have two (in our case 5, 10 or even
> > 40) or more within 1,000' of each other. Can furrent technology deal
> > with that, or will equipping all sailplanes create more problems than
> > it solves?
> >
> > Thanks
> >
> > -Tom
>
> Tom;
> I am a FAA Test Pilot who is authorized to test Transponders in new
> aircraft... I do this for a living. I also was qualified as a Hawker
> 800XP test pilot.
>
> Bottom Line - Transponders are NOT the answer! Try putting one of
> these new LED Strobe Lights on the top of your Fin instead.
>
> #1. Transponders would not solve the mid air problem unless you were
> the only one in close proximity to the attacking aircraft. Typically,
> 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)
>
> #2. If multiple gliders (or aircraft) are in the vicinity all
> squawking 1200, ATC could not tell one from the other. Mode C (if you
> have it) reports altitude, yet if the climb or descent rate is large
> (let's say greater than 1500fpm) their equipment typically faults you
> off the scope and does not report your altitude. Once again unless you
> are given a discrete squawk other than 1200 (VFR traffic).
>
> #3. If multiple gliders (or other aircraft) are in the same proximity
> on closing trajectories, the ATC system will issue warnings to the
> controller, that he must issue to the offending aircraft, to try to
> prevent them from colliding.... Unless you are in direct communication
> with ATC, they will probably get extremely miffed (read.. ask you to
> call them when you land, and they will probably find you!!) because
> they are spending more time trying to cancel these warnings to control
> other "participating" aircraft.
>
> #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.
>
> #5. I have flown in wave with a transponder equipped glider, yet I was
> talking with ATC and had clearance into the window. Always, conditions
> were VMC, even though operating in Class A airspace under an IFR Flight
> Plan.
>
> #6. Transponders are expensive... DO NOT solve the "see and avoid"
> problem.. can potentially really mess ATC up if you are not in direct
> contact with them.. and in the case of the Hawker midair..... would not
> have prevented the collision.
>
> Jettester (UP)

Eric Greenwell[_1_]

September 1st 06, 09:43 PM

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"

jettester

September 1st 06, 10:08 PM

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)

Andy[_1_]

September 1st 06, 11:14 PM

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

Eric Greenwell[_1_]

September 2nd 06, 01:55 AM

jettester wrote:
> 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?

>
> 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.

I suppose improvements in the last 18 years in their hardware, software,
and power authorizations could mean your tests are no longer useful
references for their abilities nowadays? Anecdotally, it seems like they
are better than you measured back then.

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

Eric Greenwell - Washington State, USA

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

September 2nd 06, 04:07 AM

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

Doug Haluza

September 2nd 06, 12:04 PM

One thing, if you do decide to buy a transponder or other collision
avoidance device, please support the retailers who support soaring.
Don't just look for the cheapest internet price.

5Z wrote:
> jettester wrote:
> > Bottom Line - Transponders are NOT the answer! Try putting one of
> > these new LED Strobe Lights on the top of your Fin instead.
>
> EXCELLENT response! Sounds like the "transponder" option is to get a
> Zaon MRX http://www.zaonflight.com/mrx.html It's better if I'm AWARE
> of ALL the transponders nearby instead of just trying to become visible
> to a few others with limited success.
>
> Did a quick Google search for LED strobes and these are intriguing, but
> looks like 1/3 to 1/2 amp drain, so even worse than transponder. But,
> it may be possible to rig these to flash less frequently...
>
> -Tom

James D'Andrea

September 2nd 06, 07:29 PM

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)

Kilo Charlie

September 3rd 06, 02:32 AM

Ya I'm pretty uncertain now re the take home message for those of us with
mode C installed already. I thought that it was a given that traffic with
TCAS were seeing me and that center/approach could also and vector traffic
around me. After this thread I 'm not feeling froggy about any of this. In
Phoenix and most other places I fly I have been squawking 1200 (Ely,
Moriarty) but are you guys saying that I will be ignored by ground radar due
to filtering for airspeed and by TCAS for 1200???? Glad I spent the $2000.
It all seems inane to me that we go to the effort to be seen and our reward
is being "filtered out" because some moron thinks we aren't a real threat.

Casey Lenox
KC
Phoenix

Eric Greenwell[_1_]

September 3rd 06, 03:16 AM

Kilo Charlie wrote:
> Ya I'm pretty uncertain now re the take home message for those of us with
> mode C installed already. I thought that it was a given that traffic with
> TCAS were seeing me and that center/approach could also and vector traffic
> around me. After this thread I 'm not feeling froggy about any of this. In
> Phoenix and most other places I fly I have been squawking 1200 (Ely,
> Moriarty) but are you guys saying that I will be ignored by ground radar due
> to filtering for airspeed and by TCAS for 1200???? Glad I spent the $2000.
> It all seems inane to me that we go to the effort to be seen and our reward
> is being "filtered out" because some moron thinks we aren't a real threat.

You aren't being filtered out by airspeed or code. Read the posting by
Billy Hill. Your transponder is being seen by ATC, the airliner TCAS,
and everyone with a TPAS unit, so I think your $2000 was a good value
(that's what my Becker cost me, too). We still have to worry about all
the other gliders (even those with a transponder, because I don't have a
TPAS unit yet), and some/many of the small airplanes, too.

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

Eric Greenwell - Washington State, USA

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

Kilo Charlie

September 3rd 06, 06:22 AM

> You aren't being filtered out by airspeed or code. Read the posting by
> Billy Hill. Your transponder is being seen by ATC, the airliner TCAS, and
> everyone with a TPAS unit, so I think your $2000 was a good value (that's
> what my Becker cost me, too). We still have to worry about all the other
> gliders (even those with a transponder, because I don't have a TPAS unit
> yet), and some/many of the small airplanes, too.

> Eric Greenwell - Washington State, USA

Hmm.....well maybe you missed this above from jettester Eric or he's
incorrect.....

Tom;
I am a FAA Test Pilot who is authorized to test Transponders in new
aircraft... I do this for a living. I also was qualified as a Hawker
800XP test pilot.

Bottom Line - Transponders are NOT the answer! Try putting one of
these new LED Strobe Lights on the top of your Fin instead.

#1. Transponders would not solve the mid air problem unless you were
the only one in close proximity to the attacking aircraft. Typically,
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)

#2. If multiple gliders (or aircraft) are in the vicinity all
squawking 1200, ATC could not tell one from the other. Mode C (if you
have it) reports altitude, yet if the climb or descent rate is large
(let's say greater than 1500fpm) their equipment typically faults you
off the scope and does not report your altitude. Once again unless you
are given a discrete squawk other than 1200 (VFR traffic).

I also have a Becker and will continue to believe that its better than
nothing......

KC

588

September 3rd 06, 08:08 AM

Kilo Charlie wrote:

> Hmm.....well maybe you missed this above from jettester Eric or he's
> incorrect.....

>> Mode C (if you
>> have it) reports altitude, yet if the climb or descent rate is large
>> (let's say greater than 1500fpm) their equipment typically faults you
>> off the scope and does not report your altitude.

So, the aircraft climbing or descending at a high rate are the ones
they do NOT want to know about? This had better be wrong.

I suspect jettester's info may also be a little out of date. When did
he say he hung up his spurs?

Jack

Andy[_1_]

September 3rd 06, 03:20 PM

Kilo Charlie wrote:
After this thread I 'm not feeling froggy about any of this. In
> Phoenix and most other places I fly I have been squawking 1200 (Ely,
> Moriarty) but are you guys saying that I will be ignored by ground radar due
> to filtering for airspeed and by TCAS for 1200???? Glad I spent the $2000.
> It all seems inane to me that we go to the effort to be seen and our reward
> is being "filtered out" because some moron thinks we aren't a real threat.

The money you spent on a transponder was well spent. Now you need to
save up and buy a better bull**** filter!

Andy

Andy[_1_]

September 3rd 06, 03:44 PM

Eric Greenwell[_1_]

September 3rd 06, 05:19 PM

Kilo Charlie wrote:
>> You aren't being filtered out by airspeed or code. Read the posting by
>> Billy Hill. Your transponder is being seen by ATC, the airliner TCAS, and
>> everyone with a TPAS unit, so I think your $2000 was a good value (that's
>> what my Becker cost me, too). We still have to worry about all the other
>> gliders (even those with a transponder, because I don't have a TPAS unit
>> yet), and some/many of the small airplanes, too.
>
>> Eric Greenwell - Washington State, USA
>
> Hmm.....well maybe you missed this above from jettester Eric or he's
> incorrect.....
>
> Tom;
> I am a FAA Test Pilot who is authorized to test Transponders in new
> aircraft... I do this for a living. I also was qualified as a Hawker
> 800XP test pilot.
>
> Bottom Line - Transponders are NOT the answer! Try putting one of
> these new LED Strobe Lights on the top of your Fin instead.
>
> #1. Transponders would not solve the mid air problem unless you were
> the only one in close proximity to the attacking aircraft. Typically,
> 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)
>
> #2. If multiple gliders (or aircraft) are in the vicinity all
> squawking 1200, ATC could not tell one from the other. Mode C (if you
> have it) reports altitude, yet if the climb or descent rate is large
> (let's say greater than 1500fpm) their equipment typically faults you
> off the scope and does not report your altitude. Once again unless you
> are given a discrete squawk other than 1200 (VFR traffic).
>
> I also have a Becker and will continue to believe that its better than
> nothing......

I saw jettester's posting, and I think he is wrong, based on my
information from other pilots and ATC people over the last few years.
For example, I don't think ATC has any problem distinguishing a
transponder from ground returns, regardless of the transponder's speed,
so the "MTI" comment doesn't apply. Perhaps jettester's experience is
outdated or perhaps the testing he did involved procedures that are not
normally used by ATC - I don't know.

Also, TCAS is designed to handle multiple targets, and ATC can determine
the location of transponders even if they close to each other. ATC may
not be able to get a reliable altitudes or code readings in that case,
but they know where the group is, and they are not going to let an
aircraft in contact with them fly into a swarm of aircraft.

Here is what Billy Hill posted (in part) on Aug 31 (pilots should also
read his article in the July 2006 Soaring magazine):

"Each controller is required by virtue of the ATC handbook, (7110.65 and
the management handbook 7110.3), to display ALL transponder equipped
aircraft. What the controller does have the option to do is adjust the
filter limits at his scope to exclude the encoded altitude of aircraft
which are not in his assigned airspace.
Had the transponder been turned on by the pilot involved in the
mid-air, the jet would have seen the glider on it's TCAS, and ATC
would have been issuing the glider as traffic to the jet. In the Reno
area, most glider pilots are squawking an non discrete code which
indicates to ATC that they are a glider."

People that have experimented with strobe lights have been disappointed,
because they don't help much in sunny conditions. I don't know if LED
strobes are more visible than the glass bulb type, but they do use less
current.

Enjoy your Becker - it's a far better solution than indicated by jettester.

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

Eric Greenwell - Washington State, USA

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

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

Mike Schumann

September 4th 06, 12:55 AM

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

September 5th 06, 09:56 PM

588 wrote:
> Kilo Charlie wrote:
>
> > Hmm.....well maybe you missed this above from jettester Eric or he's
> > incorrect.....
>
>
> >> Mode C (if you
> >> have it) reports altitude, yet if the climb or descent rate is large
> >> (let's say greater than 1500fpm) their equipment typically faults you
> >> off the scope and does not report your altitude.
>
> So, the aircraft climbing or descending at a high rate are the ones
> they do NOT want to know about? This had better be wrong.
>
> I suspect jettester's info may also be a little out of date. When did
> he say he hung up his spurs?
>
>
> Jack

Sorry to all: I've been gone away from my computer for the holiday!
(was soaring !)

Wow, I was trying to clear up a number of misconceptions that people
typically have concerning Transponders. Did not mean to stir up a
hornets nest. Billy Hill is telling the truth also... so don't
misconstrue my remarks.

It depends on the radar you have in your area. whether you have 'line
of sight' with the glider and transponder whether the controller can
"see" your transponder. This is a continuation of my previous comments.

#7. My comments are reflective of "current" equipment used by ATC and
probably more current transponders than any of you can afford. Not
much has changed in the last 18yrs. Yet, I confirmed my previous
statements with the ATC supervisor here in Wichita as being correct.

#8. If two or more of you are operating on the same squawk code, and
end up with converging tracks or converging altitudes (if Mode C
equipped), you WILL set off ATC's traffic warnings (unless they turn
them off for all other traffic in your/their vicinity).

#9. Transponders are a good thing to have if ATC can "see" you, and
their participating traffic has TCAS.. it will "point" you out to that
traffic. TCAS uses the ATC radar to relay your transponder code and
altitude (if Mode C equipped) to that traffic.

#10. I spoke truthfully about their (ATC) not seeing you if climbing
too rapidly (or descending). It may X'out your info on their scope as
well as your altitude.

#11. A transponder may have helped the Hawker to receive a TCAS warning
if ATC could "see" the glider transponder (line of sight), Mode C would
have reported its altitude, and MTI did not filter because the glider
was not circling. I confirmed that MTI is set 65K in this area.

Jettester (UP)

Andy[_1_]

September 6th 06, 12:18 AM

jettester wrote:
>
> #11. A transponder may have helped the Hawker to receive a TCAS warning
> if ATC could "see" the glider transponder (line of sight), Mode C would
> have reported its altitude, and MTI did not filter because the glider
> was not circling. I confirmed that MTI is set 65K in this area.
>
> Jettester (UP)

TCAS does not depend on the target aircraft responding to ATC radar.
TCAS itself performs the interogation and processes the response
independent of ground radar. Since ground radar is not required, the
MTI settings of a proximate ground radar have no influence of the
visibility of the target to a TCAS equipped aircraft.

TPAS however, does rely on the target responding to someone else.

I'll provide one reference that supports my contention. Can you
provide any that support yours?

to quote from http://www.nak.no/flynytt/download/TCAS_II_V7.pdf

Target Surveillance:

TCAS, independent of any ground inputs,
performs surveillance of nearby aircraft to
provide information on the position and
altitude of these aircraft so the collision
avoidance algorithms can perform their
function.

Eric Greenwell

September 6th 06, 01:51 AM

jettester wrote:

> #8. If two or more of you are operating on the same squawk code, and
> end up with converging tracks or converging altitudes (if Mode C
> equipped), you WILL set off ATC's traffic warnings (unless they turn
> them off for all other traffic in your/their vicinity).

This must be a common occurrence at Minden. Perhaps someone can tell us
if this situation is one reason to have separate code for gliders, since
they could turn off the collision warning for 0440?
>
> #9. Transponders are a good thing to have if ATC can "see" you, and
> their participating traffic has TCAS.. it will "point" you out to that
> traffic. TCAS uses the ATC radar to relay your transponder code and
> altitude (if Mode C equipped) to that traffic.

I didn't understand this at all: why would TCAS send an aircraft's code
to ATC, when ATC can already get it when they interrogate the aircraft's
transponder?
>
> #10. I spoke truthfully about their (ATC) not seeing you if climbing
> too rapidly (or descending). It may X'out your info on their scope as
> well as your altitude.

If the limit is set at 1500 fpm, that won't be a problem very often,
even at Minden. And TCAS will still see you, right?

--
Note: email address new as of 9/4/2006
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

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

Overlap

September 6th 06, 07:19 AM

Jettester, #9 and #11 are not correct. TCAS does not need ATC radar to
"see" another transponder-equipped aircraft. I believe you may be thinking
of TPAS. Are you familiar with that technology?

Also, my understanding of the process differs from that to which you refer
in #8, in that donflict warnings will not be triggered unless one of the
aircraft is squawking a discrete code assigned by ATC. If the situation you
describe was true, alarms would be constantly triggered due to
VFR-squawkers, which in many areas would render the display confusing at
best, and needlessly distract a controller busy separating IFR traffic.

O

"jettester" > wrote in message
ups.com...
>
> 588 wrote:
>> Kilo Charlie wrote:
>>
>> > Hmm.....well maybe you missed this above from jettester Eric or he's
>> > incorrect.....
>>
>>
>> >> Mode C (if you
>> >> have it) reports altitude, yet if the climb or descent rate is large
>> >> (let's say greater than 1500fpm) their equipment typically faults you
>> >> off the scope and does not report your altitude.
>>
>> So, the aircraft climbing or descending at a high rate are the ones
>> they do NOT want to know about? This had better be wrong.
>>
>> I suspect jettester's info may also be a little out of date. When did
>> he say he hung up his spurs?
>>
>>
>> Jack
>
> Sorry to all: I've been gone away from my computer for the holiday!
> (was soaring !)
>
> Wow, I was trying to clear up a number of misconceptions that people
> typically have concerning Transponders. Did not mean to stir up a
> hornets nest. Billy Hill is telling the truth also... so don't
> misconstrue my remarks.
>
> It depends on the radar you have in your area. whether you have 'line
> of sight' with the glider and transponder whether the controller can
> "see" your transponder. This is a continuation of my previous comments.
>
> #7. My comments are reflective of "current" equipment used by ATC and
> probably more current transponders than any of you can afford. Not
> much has changed in the last 18yrs. Yet, I confirmed my previous
> statements with the ATC supervisor here in Wichita as being correct.
>
> #8. If two or more of you are operating on the same squawk code, and
> end up with converging tracks or converging altitudes (if Mode C
> equipped), you WILL set off ATC's traffic warnings (unless they turn
> them off for all other traffic in your/their vicinity).
>
> #9. Transponders are a good thing to have if ATC can "see" you, and
> their participating traffic has TCAS.. it will "point" you out to that
> traffic. TCAS uses the ATC radar to relay your transponder code and
> altitude (if Mode C equipped) to that traffic.
>
> #10. I spoke truthfully about their (ATC) not seeing you if climbing
> too rapidly (or descending). It may X'out your info on their scope as
> well as your altitude.
>
> #11. A transponder may have helped the Hawker to receive a TCAS warning
> if ATC could "see" the glider transponder (line of sight), Mode C would
> have reported its altitude, and MTI did not filter because the glider
> was not circling. I confirmed that MTI is set 65K in this area.
>
> Jettester (UP)
>