IZ3LSV

G8MNY  > TECH     19.05.22 10:23l 79 Lines 2640 Bytes #999 (0) @ WW
BID : 22046_GB7CIP
Read: GUEST
Subj: 70cm Bowtie Beam
Path: IZ3LSV<DB0ERF<OK0NAG<OK0NBR<SR1BSZ<EA2RCF<LU9DCE<VA3TOK<VE3KPG<GB7CIP
Sent: 220519/0904Z @:GB7CIP.#32.GBR.EURO #:22046 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW


GAIN FIG 10 dB
   <................. 550mm.................>
   +                                        +
   +                                        +
   +          +                 +           +
   +       +     +           +     +        +
   +     +         +       +         +      +
   +   +             +   +             +    +   550mm
   +    +             00              +     +
   +      +         +    +          +       +
   +        +     +        +      +         +
   +           +               +            +
   +                                        +
   ++++++++++++++++++++++++++++++++++++++++++

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
                      +             +
                        +         +
                          +     +
                           +# |+
                          + # | +
                        +   # |   +
                      +     # |     +
            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


Why Don't U send an interesting bul?

73 De John, G8MNY @ GB7CIP




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