Microwave QSOs with the aid of airplane reflection

Microwave QSOs with the aid of airplane reflection Wolf-Henning Rech DF 9 IC in JN 48 iw http: //www. df 9 ic. de 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC

Content z Some theory z Observations on beacons z Experience from QSOs z Airplane tracking with ADS-B z A propagation test z Conclusion 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 2

Reflection or scatter? z Reflection: ylike a mirror: angle of incidence = angle of reflection yreflective area must be: large - smooth - plane e. g. dish reflector z Scatter: ymostly omnidirectional (with varying power density) yfrom either a rough surface or from a large number of small particles e. g. moon (EME) 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC e. g. rain (RS) 3

Geometry of DX via airplane z Large passenger and freight airplanes use a height of FL 300 - FL 400 (30. 000 - 40. 000 ft) z the airplane is close to the horizon for maximum range (very low elevation 0. . . 1°) z then the angle of incidence of the wave on the aircraft is around 3° 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 4

Maximum range via airplane z Maximum range by airplane at FL 400 at the right position and radio LOS path including refraction in the atmosphere is 1040 km z Experimental limit on 1296 and 2320 is 800 km for good probability and duration (from DF 9 IC SK 7 MW 777 km easy, SM 7 ECM 809 km difficult) 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 5

Geometry of DX via airplane Top View 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 6

Path attenuation z Reflection: z Scatter: with A : effective reflective area s : radar cross section z Example: d 1 = d 2 = 390 km, f = 1296 MHz, g. TX = 32 d. Bi, PTX = 51 d. Bm, g. RX = 24 d. Bi, PRX = -130 d. Bm results in 28. Nordic VHF Meeting 2006 Sletten A = 2. 7 m 2 s = 5000 m 2 Wolf-Henning Rech DF 9 IC 7

Duration and Doppler shift z Airplane speed = 900 km/h = 15 km/min z typical duration of one reflection is between few seconds to few minutes z Doppler shift occurs because of difference in aircraft speed perpendicular to both stations z Different Doppler shifts from various airplanes allow to differentiate between them (only CW) 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 8

Which is the best frequency? z Path attenuation is frequency independent z Pro lower frequencies: ywide beamwidth of antennas ycurvature of reflecting planes is less harmful yangle condition (incident = reflected) is less stringent ywe use more TX power (but microwave will QRO in future) z Pro higher frequencies: ymore antenna gain z Conclusion: we should try more on microwave! 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 9

Observations on beacons z Use of SPECTRAN or similar programs for audio analysis (spectrogram, waterfall display) z Airplane reflection is Doppler-shifted; frequency depends on its speed relative to both stations z Example: GB 3 MHL 1296. 830 at DF 9 IC d = 630 km 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 10

Observations on beacons z Even on local signals you can often see airplane reflected spurs below the main signal z Doppler shift changes fast when airplane is close to one of the stations z Example: DB 0 KI 1296. 840 at DF 9 IC d = 263 km Airplane reflections Direct signal 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 11

Experience from QSOs TX RX TX ON 4 IY 1296 MHz 750 m. W 360 km recorded in NAC May 2006 (each red tick is 10 seconds): just readable in CW in the peak 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 12

Experience from QSOs RX TX RX OZ 2 LD 1296 MHz 688 km recorded in NAC May 2006 (each red tick is 10 seconds): end of QSO 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 13

Experience from QSOs RX TX RX DL 7 VTX 1296 MHz 528 km recorded in NAC May 2006 (each red tick is 10 seconds): end of QSO 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 14

Experience from QSOs z Example: 23 cm NAC May 2006 DF 9 IC in JN 48 iw 17: 41 17: 54 18: 00 18: 05 18: 15 18: 20 18: 29 18: 32 18: 39 18: 45 18: 46 18: 48 18: 49 18: 56 19: 07 19: 16 20: 18 20: 19 20: 23 20: 30 20: 59 DL 1 SUZ PA 5 DD PA 3 CEG OZ 1 FF SK 7 MW OZ 9 KY OZ 2 LD SM 7 ECM DJ 8 MS DK 3 WG DK 9 TF DJ 6 JJ/p DL 3 YEE DL 5 YEE DB 6 NT G 4 EAT ON 4 IY G 4 HUP DG 1 KJG DB 5 KN G 4 BEL DL 7 VTX 559 55 53 529 53 519 529 519 52 549 56 549 54 54 59 529 519 55 57 54 54 519 28. Nordic VHF Meeting 2006 Sletten 579 56 54 519 559 519 52 569 57 539 57 57 59 529 55 57 59 54 539 JO 53 UN JO 22 IC JO 33 FB JO 45 BO JO 65 MJ JO 45 VX JO 54 TU JO 65 NQ JO 64 AD JO 72 GI JO 31 NF JO 31 LG JO 42 GE JO 42 GF JO 50 TI JO 01 HR JO 20 IV JP 02 PC JO 30 NT JO 31 NB JO 02 BI JO 62 TM 555 452 485 743 777 787 688 809 624 560 279 288 362 366 263 653 360 632 237 262 715 528 km km km km km km Airplane (? ) Airplane Airplane Airplane (? ) Airplane Wolf-Henning Rech DF 9 IC 15

Airplane tracking with ADS-B z Questions: ywhere are the airplanes now? (interesting) ywhen will an airplane be there where I need it? (even more interesting : -))) ) z Solutions: yexperience from former tests yflight plans, departure lists in the internet yreal-time tracking of airplane positions 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 16

Airplane tracking with ADS-B z ADS-B (automatic dependence surveillance broadcast mode) is a data protocoll for the transmission of information about the status of airplanes z ADS-B datagrams are transmitted by a growing number of airplanes on the transponder output frequency 1090 MHz with 1 Mbit/s in ASK z information is not encrypted (!!), frame structure is known 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 17

Airplane tracking with ADS-B z Since 2005 a non-professional ADS-B-RX is available from Kinetic Avionics (UK) 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 18

Airplane tracking with ADS-B z The SBS-1 with base station software allows real -time tracking of ADS-B equipped airplanes (GPS position, speed, heading, etc. ) z About 50% of the big airplanes are equipped (2006) z Data is visualized on a map z Reception is limited to LOS z But the 1090 channel is overloaded so distant airplanes are received only sparsly 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 19

Airplane tracking with ADS-B z Reception with omni antenna 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 20

Airplane tracking with ADS-B z Reception with 120° sector antenna 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 21

Airplane tracking with ADS-B z Reception with 1. 2 m dish and 1090 feed 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 22

A propagation test on 1296 MHz z On 23 rd Oct. 2005 we did a test >1 h between SK 7 MW and DF 9 IC on 1296 MHz (777 km) z SK 7 MW transmits dots with 2 x 2 C 39 and 4. 5 m dish 28. Nordic VHF Meeting 2006 Sletten SK 7 MW 4. 5 m dish Wolf-Henning Rech DF 9 IC 23

A propagation test on 1296 MHz z DF 9 IC receives with 4 x 35 Ele Yagi and RX AGC off z Airplanes were tracked at DF 9 IC on 1090 MHz with ADS-B RX on a 1. 2 m dish 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 4 x 35 El 24

A propagation test on 1296 MHz z During this time about 7 major airplane reflections could be observed z Audio voltage from the RX with AGC off: 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 25

A propagation test on 1296 MHz z Some reflections could be correlated with airplanes passing the „midway“ area SN Brussels Airline DAT 2556 ENE to WNW FL 320 Air France AFR 2535 ENE to WNW FL 340 28. Nordic VHF Meeting 2006 Sletten Hapag Lloyd Express HLX 3129 Berlin-Tegel to Köln FL 340 Ryan Air RYR 2336 London Stansted to Posen FL 370 Wolf-Henning Rech DF 9 IC SAS Scandinavian Airlines SK 1606 Zürich to Stockholm FL 380 Iberia IBE 3547 Berlin-Tegel to Madrid FL 330 26

A propagation test on 1296 MHz „midway“ z Best reflection from SAS SK 1606 z it was flying exactly along the radio path 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 27

2320 and 3400 MHz z 2320 MHz: ymultiple QSOs on this same path y. DF 9 IC: 1. 2 m dish -4 d. B cable loss and 250 W y. SK 7 MW: 1. 8 m dish -1 d. B cable loss and 250 W z 3400 MHz: yonly one test in the evening of May 3 rd 2006 y. DF 9 IC: 1. 2 m dish and 35 W y. SK 7 MW: 1. 8 m dish and 50 W ytwo good reflections of 1 min duration in a 40 min test, up to SSB signal strength 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 28

Conclusion z QSOs by airplane need directive reflection, not scatter z on 1296 MHz, 2320 MHz and 3400 MHz a range of 800 km is possible with good equipment z we have to use short CQ and make QSO quickly z airplanes along the radio path seem to be best z ADS-B reception may allow an airplane forecast but needs a network of receiving stations z How about 5. 7 and 10 GHz with high power? 28. Nordic VHF Meeting 2006 Sletten Wolf-Henning Rech DF 9 IC 29