AN OPERATING 15 METER 4-SQUARE ANTENNA PERFORMANCE POSSIBILITIES DICK JEDLICKA

Transcription

1 AN OPERATING 15 METER 4-SQUARE ANTENNA PERFORMANCE POSSIBILITIES DICK JEDLICKA W8PW

2 PURPOSE GAIN TECHNICAL KNOWLEDGE THRU COMPREHENSIVE LOOK AT 4-SQUARE ANTENNA CHANCE TO USE KNOWLEDGE FOR 4-SQUARE ANTENNA PLANS

3 WARNING Attendee may experience: SURPRISE CONFLICTIONS DOUBT TO DISBELIEF POSSIBLE CONFUSION DISTRUBING INFORMATION

4 15 METERS 4-SQUARE ANTENNA 4 VERTICAL ELEMENTS STEERABLE DIRECTION SYMMETRICAL BUILD EQUIVALANT QTRS (11.5 FT)----

5 ONE OF THE TWO KNOWN OPERATING 15 METER 4-SQUARE ANTENNAS IN THE WORLD??

6 OUTLINE WHY BASIC THEORY BUILDING PREDICTIONS vs MEASUREMENTS PROPAGATION REAL WORLD OPERATION LESSONS

7 WHY -- NO PERFORMANCE EXPECTATIONS -- OBSURITY -- GET ON 15 METERS -- PREVIOUS ATTEMPT -- CHALLENGE

8 BASIC 4-SQUARE THEORY

9 POWER DIVIDER & TIME DELAYS LEFT SIDE FRONT POINT REAR RIGHT SIDE - 90 deg -180 deg 0 deg - 90 deg TIME DELAYS CONTROL BOX TRANSMITTER FEED LINE

10 SIGNAL PHASING (CB) FRONT POINT (CB) ( deg) (CB) ( - 90 deg) REAR ( - 90 deg) ( 0 deg) CONTROL BOX (CB)

11 SIGNAL CLOUD FILLS NEAR FIELD (~ 22 FT RADIUS ) GROUND

12 BUILDING

13 OBSCURITY VIEW FROM HOME 200 FT

14 FLASH FLOOD DANGER-DRAINAGE CHANNELS

15 PROXIMITY OF HOME AND OTHER STRUCTURES

16 VIEW TO NW HORIZON 45 MILES

17 VIEW TO NE WITH ORGAN MOUNTIANS

18 VIEW TO SE 1 % RISE

19 1 ¼ INCH COAX TRANSMISSION LINE

20 ONE SIDE CONTROL BOX INTERIOR SHOWS PHASING TOROIDS AND DIRECTION SWITCHING RELAYS

21 60 RADIAL WIRE STAINLESS ELEMENT BASE PLATE COAX TO ELEMENT WIRE CONNECTION

22 240 VS 120 RADIAL WIRE MESH COPPER PIPE FRAME W I R E S / E L E M E N T W I R E S / E L E M E N T

23 IMPORTANT CHANGE TO ANTENNA COUNTERPOISE NE QUADRANT WITH 60 RADIALS WIRES TERMINATED ON COPPER PIPE FRAME CREATING A METAL MESH AS COUNTERPOISE (ONLY WAY TO KEEP RADIAL WIRES STRAIGHT AND DOWN ON THE GROUND) PLASTIC PALE COVERS BASE OF AL 2 INCH DIAMETER ELEMENT

24 CHARACTERISTICS TO BE MEASURED Deep Right angle & NSEW ---- Beam widths: H & V (some data) Vertical Angle (some data) Front to Back Ratio Gain Reflected Power (input / between elements)

25 DEEP NULLS -- Elements laid out N/S/E/W -- Peaks/Nulls fixed directions -- Nulls about 20 degrees wide -- Nulls: N/S/E/W; ~ 30DB deep -- See polar projections maps

26 NULL DIRECTION - RED BEAM CENTER - GREEN POLAR PROJECTION - LAS CRUCES CENTERED

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28 HORIZONTAL BEAMWIDTH DISAGREEMENT MEASUREMENTS VERSUS PREDICTIONS

29 HORIZONTAL PATTERN PREDICTION (BLACK) MEASURED (RED)

30 HORIZONTAL BEAMWIDTH --- Measured: ~45 deg vs Model: ~90 deg --- Plot Known bearing of a signal vs Depth of Null ( 0 dbm to -30 dbm --- Measured at ~ 0-5 vertical deg using >4000 mi signals --- Used 240 terminated radials (mesh) --- Model prediction at 14 deg, Vert beam vertical angle using 8 radials

31 VERTICAL ANGLE OF MAIN BEAM

32 VERTICAL PATTERN PREDICTED {ONLY 8 RADIALS} (BLACK) ESTIMATED {SOME DATA} (RED) DX SIG - 0 TO 5 DEG

33 VERTICAL ANGLE --- degrees with signal 300 ft --- Strong 2 degrees --- Decreased 5 degrees --- >6,000 mi stronger signals --- Est Vertical angle: ~0 degrees --- Est Vert beam width: ~10 deg

34 REFLECTED POWER --- Transmission Line: 1-3% measured at amplifier --- Element imbalance 2-8 w measured at dummy load in radio room

35 FRONT TO BACK RATIO --- Instantaneous reversal --- Test against many DX stations --- Receive signals only --- Assure station in beam center --- Ratio F/B: 20db to 25db

36 GAIN Relative to something????: - Isotropic: (models) ~10 dbm - Perfect dipole: (models) ~7dbm - Measures against imperfect, separate, calibration vertical antenna: 30 ft. high ~15-18 dbm

37 PREDICTED VS ACTUAL SUMMARY CHARACTERISTIC PREDICTED ACTUAL H BEAMWIDTH: 90 DEG 45 DEG V BEAMWIDTH: 14 / 10 DEG 5-10 DEG V ANGLE: 30 / 10 DEG 5-0 DEG* REFLIX POWER: 0 % 1 3% F/B: 25 dbm dbm GAIN: 7 /? dbm? / 18 dbm EFFICENCY: ********** ******** * INFINITE METAL MESH COUNTERPOISE PREDICTS 0 dg

38 ESTIMATED EFFICIENCY % NOMIN ANT ( 4 SQUARE) TRANS LINE TUNER/CONTR INNER CABLE ANTENNA GRD ABSORB TOTAL EFF

39 ESTIMATED EFFICIENCY % NOMINAL ( 4 SQUARE) TRANS LINE (100) TUNER/CONTR (60 70) INNER CABLE 0 (90 95) ANTENNA (50-80) GRD ABSORB (30 100) OVERALL % ( 8 53)

40 IONOSPHERIC PROPAGATION ( not ground wave or scatter)

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43 IONOSPHERIC PROPAGATION RERADIATED SIGNALS -- IN ANGLE = OUT ANGLE -- LOWER ANGLE GETS LESS LOSS ON DX PATHS, >2000 MILES -- LESS LOSS IF NO EARTH ENCOUNTER, NO ABSORBTION

44 IONOSPHERIC POLARIZATION TRANSFORMATION RERADIATED O MODE IONOSPHERE X MODE VERTICAL OR HORIZONTAL

45 IONOSPHERE POLARAZATION TRANSFORMATION - RERADIATION VERTICAL IONOSPHERE OR HORIZONTAL

46 O AND X MODES POLARIZATIONS O MODE X MODE counter clockwise clockwise

47 IONISPHERIC POLARIZATION SUMMARY In Vertical = Elliptical Out In Horizontal = Elliptical Out O Mode In = O Mode Out X Mode In = X Mode Out

48 O & X MODE PROPAGATION DIFFERENCES (Depends upon shape of earth s magnetosphere) (Receive/Transmit signal paths not recepical) PATHS ARRIVAL TIMES BEARINGS SIGNAL STRENGTHS VERTICAL ANGLES

49 TYPICAL REAL WORLD OPERATING EXAMPLES OF 4-SQ s UNIQUE CHARACTERISTICS REUNION ISLAND INCIDENT PARAGUAY-ANTARTICA INCIDENT 5 YEAR PROPAGATION EXPERIMENT

50 REUNION ISLAND INCIDENT (Distance 11,100 miles, South Indian Ocean) FR4MR breaks into W8PW / AA0A QSO Signal report for W8PW, only signal on band Only signal on band, reason for calling Not unusual: 120 countries initiated contacts Example of extremely low vertical beam angle

51 PARAGURY / ANTARTICA INCIDENT

52 PARAGUAY - ANTARTICA INCIDENT - Paraguay on 1st call from pileup - Paraguay works Antartica - Get Antartica qsy down ten - 10 min contact with Antartica - Antartica not hear na pileup - Antartica gets no further calls - Another example: low angle

53 FIVE-YEAR PROPAGATION EXPERIMENT

54 5 YEAR PROPAGATION EXPERIMENT (still ongoing every day) 6400 mi (PROPAGATION ONLY VARIABLE) HELD CONSTANT: -OPERATORS 5 -POWER 1KW 250 FT -TIME OF DAY 0 FT JA3CZY -IC 7600 W8PW

55 JA3CZY ANTENNA: 5 EL YAGI 250 FEET

56 JA3CZY 15M 250 ft

57 CONTACT SENERIO --- Establish clear frequency --- Usually signals slowly emerge out of noise --- Usually only signals on band to 20 Minutes to S-9

58 SUCCESSFUL CONTACT CRITERIA ---- Clear recognition of calls ---- Exchange of further information Weather Heath Band conditions

59 SIGNAL REPORTS --- NOT SIMULATANUEOUS --- Only signals on band --- Strongest on band --- Only from No. America --- Strongest from No. America

60 SUCCESSFUL & UNSUCCESSFUL CONTACTS -- Unsuccessful Successful 699 (as of Feb 24, 2016)

61 4-SQUARE DX BENIFITS ---- Most antenna gain at very low vertical angle of ~0-5 degrees ---- Min transmission path loss ---- Maximum strength of incoming DX signals from low angle ---- Wide H beam gets O & X modes ---- Quick directivity changing avoids noise and captures non-great circle paths

62 4-SQUARE NEGATIVE FEATURES ---- PERMANENT -30DBM NULLS AT N/S/E/W, NEED S9 MIN SIG ---- LOW EFFICIENCY ~10% TO ~50%, LOSS OF 1-3 S UNITS

63 LESSONS FOR 80M & 40M 4-SQUARES NOW & PROPOSED --- Operating scale model --- Basis for comparison --- Indicator of possible perturbing factors --- Site selection factors --- Realization of potential --- Verification current behavior --- Realization of benefits and limitations

64 --T H E E N D--

65 QUESTIONS