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ZS2ABF > TECH 02.04.08 19:00l 42 Lines 1942 Bytes #999 (0) @ WW
BID : 670266ZS2ABF
Read: GUEST
Subj: Re: 70cm Bowtie Beam
Path: IZ3LSV<IW2OHX<IQ0LT<I0TVL<CX2SA<VK4TRS<ZS0MEE<ZS0ELD
Sent: 080402/0754Z @:ZS0ELD.ELD.ZAF.AF #:58736 [58737] FBB7.01.35 alpha
From: ZS2ABF@ZS0ELD.ELD.ZAF.AF
To : TECH@WW
Hi all,
I have just read John's (G8MNY) "70Cm Bowtie Beam".
I have also made several of these for 70 Cm's and 2.4 Ghz(for FSTV).
They work very well so John is correct when he says, he has worked many DX
with this type of Aerial.
The one I have on my tower has no Grid Reflector, it's just the dickey bow. I
made mine out of a piece of 6 mm aluminium thin wall, plastic coated, Car fuel
line piping. I knocked nails into a piece of wooden board to make a template
at the correct measurements. Then I just bent the tubing around the nails.
Our local Radio club was on a field day one weekend and I worked them 5:9++
with 10 Watts at a distance of 80 Km.
I also have another 70Cm aerial with 5 reflectors at the rear of the Driven
Element. These are spaced parallel to the driven bowtie at the same distance
as John's Metal Grid design. This is used if I need the aerial to be
directional.
The 2.4Ghz bowtie is just a down scale of the 70 Cm one.
The reflector I used is a solid metal thin disc 120mm in diameter. The driven
element was made out of Brazing rod. Each side of the bow is 32mm long.
The driven element is positioned +- 20mm from the circular Reflector.
I used a piece of "Cerflex" coax which has a solid Copper outer to feed the
Driven element, which can be soldered directly on to the outer and inner of
this coax.
A hole was cut in the middle of the disc and the Coax was pushed through it to
the correct matching length (20MM in my case) and the outer solid copper was
then soldered all around to the disc. I then soldered a connector to the back
side of the Disc reflector. With this Aerial I Tx'd and RX'd pictures on
2.4GHz with only 15 Milli Watts of power, over a distance of 16.8 Km, so it
must work.
Try this design as it is so easy to make.
regards, Peter ZS2ABF.
73 - Peter, ZS2ABF @ ZS0ELD
Message timed: 09:44 on 2008-Apr-02
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