AirNav Systems Forum
AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: Judwin45 on June 23, 2014, 09:55:51 PM
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Hi
Can anyone suggest how I have picked up TF-BBH at a range of 290miles when my normal max range is about 114 miles.
I think I have attached a screen shot!
Regards
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Hi Judwin, every once and awhile, I get returns like that....However I had my antenna up over 35 Meters..that may have helped... You seem to have very limited range, so I cannot explain it. Maybe the signal was reflecting off of an object...
Jason
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Another possibility is that the aircraft was within your normal range but reporting a wrong position. A B734 is quite likely not to have GPS.
Maybe you've done it already, but a little research on the flight might tell you if the reported position was close to its actual route.
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Rod has probably hit the nail on the head.
There is another possibility - Thermal Inversion.
When layers of warm air form above layers of cold air, the condition known as temperature inversion develops. This phenomenon causes ducts or channels to be formed, by sandwiching cool air either between the surface of the earth and a layer of warm air, or between two layers of warm air. If a transmitting antenna extends into such a duct, or if the radio wave enters the duct at a very low angle of incidence, vhf and uhf transmissions may be propagated far beyond normal line-of-sight distances. These long distances are possible because of the different densities and refractive qualities of warm and cool air. The sudden change in densities when a radio wave enters the warm air above the duct causes the wave to be refracted back toward earth. When the wave strikes the earth or a warm layer below the duct, it is again reflected or refracted upward and proceeds on through the duct with a multiple-hop type of action.
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Hi
I have picked up the same aircraft (TF-BBH, flight TAY29V) tonight at 2050 local time again at a range of over 200 miles over France.
The only info from the internet suggests a flight between Liege and Dublin. Has anyone else picked up this flight tonight.
No big deal, I am just intrigued.
Regards
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Real position 401 nm or 742 Km. Amazing !!!!