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G8MNY > TECH 21.12.23 11:24l 77 Lines 2638 Bytes #999 (0) @ WW
BID : 62946_GB7CIP
Read: GUEST
Subj: 70cm Bowtie Beam
Path: IZ3LSV<DB0ERF<DK0WUE<GB7CIP
Sent: 231221/1024Z @:GB7CIP.#32.GBR.EURO #:62946 [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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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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