Spectrum Strips of OH7HJ Dual Rx Aircraft Scatter Experiment Setup. Listening to AS on OIRT 1 TV carriers. Incoming plane high doppler on each strip right and departing low doppler on left. Spectrogram strips plot as a pair from up added with an amplitude graph at right. Time Finnish local. Rx loc KP42QP. Receivers are 2 x FT100D, mode CW/USB with 500 Hz filters.
Aerial for St. Petersburg TV is a 4-el horizontal dipole array 12 m above ground built for large aircraft radar signature observing, with element end dip directed to St Petersburg Tx to attenuate signal strength increase during carrier crossing. The aerial for Segezha TV is a diagonally polarized 4-el yagi 5 m above ground is, dir 100.
<-- Left strip: St. Petersburg TV, KO59DX dist 300 km, bearing 170, freq 49749.975 kHz.
<-- Right strip: Segezha Nadvoitsy TV, KP73CW dist 281 km, bearing 057, freq 49757.818 kHz.
On Segezha TV freq aircraft flight paths are usually almost parallel to Rx-Tx line which makes aircraft doppler visible as a dotted interference track which separates from center as plane passes Rx or Tx. Segezha carrier has two +-50 Hz size bands. An unknown Tx is 12 Hz below it at bearing abt 140.5 degrees. There are also other unknown distant TV carriers and side bands which plot as those curious spread spectrum pings and bursts visible on strips mostly through Electric Discharge Scatters (EDS).
Lisää: Keskustelu, väitöskirja: Aircraft tracking and classification with vhf passive bistatic radar (PDF / HTML)
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