Squawk code and altitude would be a good indicator. Any aircraft within 2NM (and approaching), under 2500ft, squawking 1200 would be a very likely target....or you are getting near the pattern of the local airpark.Quote:
Originally Posted by swarga
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Squawk code and altitude would be a good indicator. Any aircraft within 2NM (and approaching), under 2500ft, squawking 1200 would be a very likely target....or you are getting near the pattern of the local airpark.Quote:
Originally Posted by swarga
Well the test happened earlier today. I rode in the airplane and had the birdseye view. Many runs were made starting at 2500 ft and then subsequent runs at 1000-1500 ft.
I have videos from the airplane, but they are pretty boring. I'd say at 2500ft or higher its very difficult to identify car make. Much easier at 1500 or below.
Switch has the test results and videos of the device in operation in his car.
Most areas that the speed traps are being run are not "controlled" airspace. Technically no transponder is required. However even the most basic VFR aircraft have transponders and you always turn them as a matter of standard procedure. I don't think any pilot (aside from smugglers) would ever disable it.Quote:
Originally Posted by brasstownbald
I don't think there's any uncontrolled airspace in So.Fl around or south of West Palm Beach other than the Everglades is there?
I haven't seen a chart for these areas in years.
Thanks for the frequency.Quote:
Originally Posted by brasstownbald
I just checked and the 396xt gives "out of band" error. ;-(
hmmmmm...
wouldn't an AM radio pickup 1090 MHz ?
nevermind..AM radio is KHz
There's prolly a Radio Shack kit or something that wlll.
here's a link on building one.....not for the electronically faint-hearted
http://www.lll.lu/~edward/edward/adsb/Very#37;20Simple%20ADSB%20receiver.html
I'd like to start out by thanking THX and his pilot friend. Had it not been for their efforts, I would not have been able to test the TPAS in this way. I am truly grateful that you guys went to the trouble to do this, and I hope that this will help others who are seeking a usable countermeasure for airborne VASCAR.
Overall Impressions:
Perhaps the one most important things that we learned in this was that the ideal detection of an aircraft would occur around 2 miles from the aircraft. This is of course with the aircraft flying at 1000 feet, and assuming you are already near the lines (and need to slow down ASAP).
Also, tracking a vehicle was significantly more difficult at 2500 feet. This would suggest that an actual speed trap is more likely to occur near 1000 feet.
It is also important to note that a less than ideal detection would still work for you, as long as you are aware before reaching the VASCAR lines.
The TPAS's estimated distances also appeared to be correct by our own visual estimation. We also noticed that from the car, we were only able to get a visual one time at 1000 feet at about half a mile. From the plane, THX was able to spot us each and every time we called in. Lesson: Your chances of spotting an airplane with the naked eye are nearly zero, even at 1000 feet.
Methods:
Initially, we had been planning to base all distances off of a GPS coordinate that was at the center of the 2 mile test strip. The plane would fly over the strip in a 2 mile oval pattern, while we drive out of the area, make a u-turn, then approach the test strip. We would note our initial detection range, first alert range, and dire warning range relative to the GPS coordinate. We would also call out our position on the radio at each warning, so that THX could try to establish a visual and get an idea if he realistically could track us in a speed trap situation from that altitude and distance.
The above method was used at 2500 feet.
This approach presented several problems, which required that we change a few things when we got to the 1000 foot tests. The problems were:
- The range of our hand held radio was not enough to allow us to leave the area in order to determine first detection range.
- Due to the racetrack pattern of the aircraft, and our inability to drive further out, we had difficulty correlating the position of the plane with the GPS coordinate and our own position.
Because of this, we treated our 1000 foot results differently.
- We recorded distances as given by the TPAS. Then tried to reconcile that with THX's visual estimation.
- We kept our U-Turns closer to the test course, to avoid loss of radio contact.
Test Results:
TCA Mode @2500'
Initial detection - 3 Miles (we had been tracking another aircraft from 8 miles out. The TPAS only started tracking our plane when it became the closer target).
First Alert - 0.5 Miles from test coordinate, 1 Mile from plane
Second Alert - 375 yards from coordinate, 0.5 Miles from plane
Enroute Mode @2500'
Initial detection - Not tested (we did not lose contact when 7 miles from test strip center)
First Alert - 2 Miles from test center (2 miles from aircraft too)
Second Alert - 1.5 Miles from test center (1 Mile from aircraft)
TCA Mode @1000'
Initial detection - Not Tested (Never lost contact @4.5miles)
First Alert - 1 Mile
Second Alert - 0.5 Miles
Enroute Mode @1000'
Initial detection - Not Tested (Never lost contact)
First Alert - 2 Miles
Second Alert - 1 Mile
Alerts:
The alerts on the TPAS are intended for collision avoidance in an aircraft. The alerts are really geared more for that purpose. You will actually hear the the alerts in the video. But I will clarufy for those who aren't going to bother with the vids.
Initial detection - The TPAS begins to display a number to show the distance to the nearest aircraft.
First Alert - a tone follwed by "Monitor Traffic" (Means aircraft nearby)
Second Alert - "Traffic alert, obtain visual contact".(Means aircraft danger close)
Modes:
Standby - For sitting on runway with dense traffic. (I just turn it off if I don't need it)
TCA - For high traffic areas. Only alerts to very close traffic and has less range.
Enroute - For travel at cruising speed. Alerts farther out and has greater range.
Conclusion:
After this testing I am convinced that this method, while imperfect, presents the best chance of detecting presence of airborne VASCAR speed traps in your path. You should always be aware of the nearest aircraft while driving in areas prone to this type of trap, and look for lines while you are scanning ahead for other traffic enforcement.
Alerts of nearby aircraft at 2 miles distance are highly desirable, though not necessary. Shorter range warnings can still work as long as you spot the lines before you pass over them.
The emphasis here is that this is a tool that adds to your situational awareness. If you are merely waiting for an alert to start looking for lines, the chances of you adjusting your speed in time go way down. As always, Be Alert!
Videos:
This is a video from the drive out to the test site.
http://www.youtube.com/watch?v=9DN2fFpuYXw
This video shows actual alerts sounding as we near the test aircraft.
http://www.youtube.com/watch?v=pwEJZu5a0kQ
THX has some footage from the plane. We will get that posted as soon as we can, so you can get an idea of whathes was seeing up in the plane.
Excellent work!
GTO_04
Please excuse the picture quality. Here is a frame grab from one of the passes. Plane headed south, car headed north, estimated distance, 2500ft. Airplane altitude was about 1200 ft.
http://www.reddevilstudios.net/quick...ANE-SWITCH.jpg
Unless it's already been asked...
Were you able to see any VASCAR markings on the road and if so, what was the highest altitude you could clearly see them?
Also, Is timing between marks the ONLY way they can get you from aircraft?