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#1
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Air traffic detection question
Has anyone flown with any of these new "portable tcas" devices? I
recently got a Monroy ATD-300, which is the lowest price, that gives range and altitude, but have been very disappointed in the performance. My experience is that the altitude and range of aircraft it is reporting are constantly changing drastically. |
#2
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FISHnFLY wrote:
Has anyone flown with any of these new "portable tcas" devices? I recently got a Monroy ATD-300, which is the lowest price, that gives range and altitude, but have been very disappointed in the performance. My experience is that the altitude and range of aircraft it is reporting are constantly changing drastically. Thats sad news, I've been interested in the purchase of that model, mainly because of its "best deal" pricing as well... |
#4
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James M. Knox wrote:
I haven't had a chance yet to put an ATD-300 through it's paces, nor to compare it to the latest new crop that have come out in the last few months. I do have an ATD-200 in my plane and find it somewhere between useful and toy. Toy, because it probably only identifies about 30% of the traffic in a useful fashion (has a habit of not lighting up until the traffic has passed G). Useful, because it sometimes does alert me to look for traffic out in the boonies, when there hasn't been another aircraft within 100 nm for the last 2 hours (hard to keep a good scan going under those conditions). A large percentage of the time it gives false alarms. Are you using the included antenna or an external one? I like the fact that the new model allows you to check your own equipments ouputted signals... None of these are going to give you anything more than a very loose idea of range. Any appearance of good range information is a lie -- a big smoothing algorithm that makes it look like good data, but still may be grossly inaccurate. The older units did NOT do a real decode on altitude and hence might trigger on a jet 30,000 feet above you, and fail to detect a '172 flying 200 feet below. The newer ones are supposed to pick up the transponder altitude, but probably have trouble keeping it matched to the appropriate target. [I develop algorithms for the military to track airborne threat targets and it can get complicated.] Does it vary the altitude substantially when you are pretty sure there is only one threat nearby? I'm sure the plane itself will always act as a shield, depending on where the target aircraft might be located... |
#5
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James M. Knox wrote:
I do have an ATD-200 in my plane and find it somewhere between useful and toy. Toy, because it probably only identifies about 30% of the traffic in a useful fashion (has a habit of not lighting up until the traffic has passed G). Useful, because it sometimes does alert me to look for traffic out in the boonies, when there hasn't been another aircraft within 100 nm for the last 2 hours (hard to keep a good scan going under those conditions). A large percentage of the time it gives false alarms. That just about NAILS it for what mine does for me. I'm starting to get curious about what the newer ones can do, but to act on that curiosity, I need to sell my ATD-200. If anyone's interested, email me. I'd sacrifice it for $250 plus shipping. |
#6
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I couldn't speak for the 200 model to be honest with you. The model I
got is the ATD-300. I watched it closely for a while and it was very hard to understand what it was tracking. The NM half would show anywhere between 5 to 0 and the altitude would jump around a lot. At times it would appear to be functioning correctly, but then it would go back into a very random cycle of range and altitude. If I turn off my transponder it appears to settle down a bit. It may be having a hard time trying to hear my transponder, but I can't tell for sure. At one point I watched a twin Cessna fly within a half mile of me and about 200-400 feet above me, but the only thing I got on the display was that it was somewhere between 4 miles and 0 miles and above me 100 feet, then it would report below me 300, then show *my* altitude with no range. Most of the time the range would change from 4 or 5 miles to 0-1 miles within 5 to maybe 10 seconds. I think the ATD-300 is the lest expensive out there, doesn't appear to be very accurate in WHAT it displays. "James M. Knox" wrote in message ... (FISHnFLY) wrote in om: Has anyone flown with any of these new "portable tcas" devices? I recently got a Monroy ATD-300, which is the lowest price, that gives range and altitude, but have been very disappointed in the performance. My experience is that the altitude and range of aircraft it is reporting are constantly changing drastically. I haven't had a chance yet to put an ATD-300 through it's paces, nor to compare it to the latest new crop that have come out in the last few months. I do have an ATD-200 in my plane and find it somewhere between useful and toy. Toy, because it probably only identifies about 30% of the traffic in a useful fashion (has a habit of not lighting up until the traffic has passed G). Useful, because it sometimes does alert me to look for traffic out in the boonies, when there hasn't been another aircraft within 100 nm for the last 2 hours (hard to keep a good scan going under those conditions). A large percentage of the time it gives false alarms. None of these are going to give you anything more than a very loose idea of range. Any appearance of good range information is a lie -- a big smoothing algorithm that makes it look like good data, but still may be grossly inaccurate. The older units did NOT do a real decode on altitude and hence might trigger on a jet 30,000 feet above you, and fail to detect a '172 flying 200 feet below. The newer ones are supposed to pick up the transponder altitude, but probably have trouble keeping it matched to the appropriate target. [I develop algorithms for the military to track airborne threat targets and it can get complicated.] Does it vary the altitude substantially when you are pretty sure there is only one threat nearby? ----------------------------------------------- James M. Knox TriSoft ph 512-385-0316 1109-A Shady Lane fax 512-366-4331 Austin, Tx 78721 ----------------------------------------------- |
#7
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Indeed sad. I've been interested in an extra set of "eyes" ever since what
initially appeared to be a bird turned into a mooney faster than you can say Ovation Dx. I can't tell you how many times I've watched planes fly by me without a peep from flight following. Anyone had experience with the SureCheck RX series transponder detectors? I guess I'll have to just buck up and get a mode-s transponder w/MFD. -Brian "Darrel Toepfer" wrote in message .. . FISHnFLY wrote: Has anyone flown with any of these new "portable tcas" devices? I recently got a Monroy ATD-300, which is the lowest price, that gives range and altitude, but have been very disappointed in the performance. My experience is that the altitude and range of aircraft it is reporting are constantly changing drastically. Thats sad news, I've been interested in the purchase of that model, mainly because of its "best deal" pricing as well... |
#8
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Darrel Toepfer wrote in
: Are you using the included antenna or an external one? I'm using the included antenna still. There is no doubt that a dual (high-low) antenna would be a big help. However, I often see the threat aircraft pass directly in front of my plane and nothing from the ATD until it is well past. The ATD antenna had a clear view - so I suspect the problem is more with shadowing of the transmitting antenna. Unfortunately, there is nothing that can be done about this on the ATD- equipped aircraft. I like the fact that the new model allows you to check your own equipments ouputted signals... True. Even the ATD-200 had a light to alert you that you were responding to a ping. And my GPS tells me what my xpndr encoder is saying. That still leaves faults in the xpndr itself (transmitting false information) but not a big problem. I'm sure the plane itself will always act as a shield, depending on where the target aircraft might be located... True. I know aircraft with Skywatch installed, complete with the top and bottom antennas. That's a $20K+ system, and still they see aircraft "appear and disappear" in certain quadrants. Heck, even ATC (which typically has a better geometry) will see aircraft drop the Mode-C when the plane is turning, or when some other part of the plane intervenes. That could be fixed with a more sophisticated xpndr system, but no one is going to propose that much money to upgrade the entire fleet. ----------------------------------------------- James M. Knox TriSoft ph 512-385-0316 1109-A Shady Lane fax 512-366-4331 Austin, Tx 78721 ----------------------------------------------- |
#9
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(FISHnFLY) wrote in
om: I couldn't speak for the 200 model to be honest with you. The model I got is the ATD-300. I watched it closely for a while and it was very hard to understand what it was tracking. The NM half would show anywhere between 5 to 0 and the altitude would jump around a lot. Can you define "a lot"? The range problem is something I would expect. But the altitude (if there is only one target anywhere near) should be accurate. Having said that, both your altitude and that of the threat aircraft can be jumping around by at least 100 feet (for a minimum "jitter" of a couple of hundred feet). So... Are you only seeing it "jump around a lot" +/- maybe 300 feet? Or is the altitude readout REALLY varying massively? ----------------------------------------------- James M. Knox TriSoft ph 512-385-0316 1109-A Shady Lane fax 512-366-4331 Austin, Tx 78721 ----------------------------------------------- |
#10
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James M. Knox wrote:
Darrel Toepfer wrote: Are you using the included antenna or an external one? I'm using the included antenna still. There is no doubt that a dual (high-low) antenna would be a big help. However, I often see the threat aircraft pass directly in front of my plane and nothing from the ATD until it is well past. The ATD antenna had a clear view - so I suspect the problem is more with shadowing of the transmitting antenna. Unfortunately, there is nothing that can be done about this on the ATD- equipped aircraft. But did they have a working transponder? g Thanks for the reply... |
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