• 70cm Bowtie Beam

    From G8MNY@21:5/101 to WW on Wed Aug 21 10:05:12 2019
    G8MNY TECH 21.08.19 04:29l 77 Lines 2638 Bytes #365 (0) @ WW
    BID : 18344_GB7CIP
    Subj: 70cm Bowtie Beam
    Path: OK0NBR IR2UBX IW2OHX IR1UAW IQ5KG I0OJJ EA2RCF CX2SA GB7CIP
    Sent: 190821/0721Z @:GB7CIP.#32.GBR.EURO #:18344 [Caterham Surrey GBR]
    From: G8MNY@GB7CIP.#32.GBR.EURO
    To : TECH@WW


    GAIN FIG 10 dB
    ................. 550mm.................
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    + + + + + + 550mm
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    ++++++++++++++++++++++++++++++++++++++++++

    SIZE OF ELEMENTS(INSIDE) 170_175mm, ELEMENTS MADE FROM 6MM CABLE

    REFLECTOR MADE FROM GARDEN MESH (SQUARES NO MORE THAN 15_20mm)

    CLOSE UP OF BOWTIE ELEMENTS
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    + +
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    +# |+
    + # | +
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    BRADE OF COAX CENTRE OF COAX

    THE BOWTIE IS MADE FROM 1 PIECE OF CABLE ( LIKE 2 W'S PUT TOGETHER BUT NOT JOINED IN THE MIDDLE)

    SOLDER COAX TO BOWTIE AS SHOWN IN CLOSE UP

    DISTANCE OF BOWTIE FROM REFLECTOR 100mm. MOVE IN & OUT TO VSWR.

    TO SUPPORT BOWTIE USE 19mm PLASTIC OVERFLOW TUBE.
    TO FIX ONTO MESH USE A STRAIGHT PLASTIC OVERFLOW TANK FITTING.
    YOU CAN ALSO USE A TANK FITTING ON THE BOWTIE END.
    CUT A CROSS SHAPE DOWN THE THREADED END & FIT BOWTIE INTO CUT-OUTS.
    FEED THE COAX DOWN PLASTIC OVERFLOW FIX BACK NUT ON THREADED END.
    INSERT A PLASTIC WINE CORK INTO END TO STOP FITTING FROM COLLAPSING.
    TIGHTEN BACK NUT ONTO BOWTIE.
    IF THE BOWTIE SEEMS FLOPPY YOU CAN FIT 2 22mm POLY WASHERS NEXT TO THE
    BACK NUT/BOWTIE SANDWICH.
    TO WATERPROOF ROUND COAX JOINTS & PLASTIC FITTING USE SILICON MASTIC.
    TO MOUNT THE BOWTIE BEAM I USED A TV U BRACKET. THIS WAS BOLTED TO THE BACK OF THE REFLECTOR.

    DIMENSIONS & MATERIALS USED

    SIZE OF MESH FOR REFLECTOR 550mm SQUARE
    DISTANCE FROM REFLECTOR TO BOWTIE 100 MM APPROX
    SIZE OF ELEMENTS(INSIDE MEASUREMENTS) 170 - 175mm

    REFLECTOR GARDEN MESH ( 15-20mm SQUARES )
    2 PLASTIC STRAIGHT TANK CONNECTORS ( LONG THREAD IF POSSIBLE )
    PLASTIC OVERFLOW PIPE
    PLASTIC WINE CORK
    6mm CABLE
    SILICON MASTIC
    TV U BRACKET

    LASTLY HAVE FUN BUILDING THE BOWTIE. I HAVE USED THIS ANTENNA FOR 10 YEARS & HAVE WORKED SOME GOOD DX.
    IF YOU HAVE ANY PROBLEMS ON BUILDING THE BOWTIE BEAM DROP ME A LINE.
    TO ANDY G6OHM @ GB7HOL.22#.GBR.EU E.O.F


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