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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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


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