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A REMOTE STEERABLE RECEIVING ARRAY FOR 1.8 MHz GREG SMITH ZL3IX.

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Presentation on theme: "A REMOTE STEERABLE RECEIVING ARRAY FOR 1.8 MHz GREG SMITH ZL3IX."— Presentation transcript:

1 A REMOTE STEERABLE RECEIVING ARRAY FOR 1.8 MHz GREG SMITH ZL3IX

2 REASON FOR THE PROJECT TO STUDY SKEWING ON LONG PATHS. TO AID THE RECEPTION OF WEAK DX SIGNALS.

3 REMOTE STATION BLOCK DIAGRAM

4

5 ANTENNA DESIGN REQUIREMENTS. BEAM WIDTH NOT EXCEEDING 60 DEGREES. MUST BE STEERABLE TO COVER ALL COMPASS POINTS MUST FIT INTO A REASONABLE SIZE, eg 1 HECTARE

6 THE BEVERAGE ANTENNA Long low wire about 2-3m off ground Needs to be about 2 wavelengths long.

7

8

9 BROADSIDE ENDFIRE ARRAY

10 100X21m BSEF ARRAY

11

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13 92X38m BSEF ARRAY

14 ELEMENT CHOICE SHORT LOADED VERTICAL SHORT VERTICAL WITH Hi Z BUFFER. SMALL LOOP

15

16 FET BUFFER

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20 CONTROLLER 16F876 PIC WIZ C DECODES SERIAL CONTROL DATA PROGRAMS DDS IN Rx SELECTS CORRECT ELEMENTS FOR REQUIRED DIRECTION

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22 UHF Rx/Tx Rx - MODIFIED DEVELOPMENT MODEL TB mW WHEN ASLEEP Tx - TM8100 PA CTCSS TONE TO SWITCH ON LACK OF CARRIER FOR 4 s, OR A DIFFERENT CTCSS TONE, SWITCHES SYSTEM OFF. DATA LINK 4800 Bd RAW RS232

23 POWER SYSTEM

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25 LOCAL STATION BLOCK DIAGRAM

26 TUNER BLOCK DIAGRAM

27

28 THE UHF LINK

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32 TELEMETRY PARAMETERS - 160m RSSI, UHF RSSI, Batt Volts, Solar Volts. SUPERIMPOSED ON AUDIO 300 Bd FSK, Tones at 1850 and 2150 Hz Telemetry has HP filter at Tx Audio has LP filter at Rx

33

34 THE TELEMETRY RECEIVER

35 PROBLEMS UNEQUAL ELEMENT PICKUP -PREAMP GAIN VARIATIONS

36 PROBLEMS UNEQUAL ELEMENT PICKUP -PREAMP GAIN VARIATIONS -PICKUP FROM COAX BRAID

37

38 PROBLEMS FADING ON UHF LINK -AIRCRAFT FLUTTER CAUSES DEEP SIGNAL FADES ON BOTH UP AND DOWN LINKS. -SLOW FADING DUE TO GENERAL TROPOSPHERIC PROPAGATION VARIATIONS NOISE FROM COMMON Tx/Rx ANTENNA -HOSE CLAMPS SERIOUS OFFENDERS -METAL MOUNTING PLATE -PVC TAPE UNDER U BOLTS -COAX BRAID

39 TESTING

40

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