[VHFcontesting] 432 Yagi Design Help

Thomas Miller ac5tm at bellsouth.net
Tue Oct 28 01:52:58 EST 2003


Downeast Microwave sells the driven element dipoles mentioned in the ARRL
handbook that are made with a piece of rigid coax etc. For two antennas I
would think of purchasing them rather than finding all the materials.
Tom AC5TM
----- Original Message -----
From: "David Vondrasek" <n5ito at arrl.net>
To: <vhfcontesting at contesting.com>
Sent: Monday, October 27, 2003 11:03 PM
Subject: [VHFcontesting] 432 Yagi Design Help


> I have an old 432 18 ele Sat cross beam ( 9 ele V - 9 ele H ) with a shot
> relay/phasing box. With an 80 element DX-432 array going up very soon and
I
> don't use Satellites I really had no use for it. Then I got  bored and was
> thinking of extending the boom and making on hell of a long boom yagi out
> of it , maybe 2 and stacking them for EME or 432 tropo work and give me an
> antenna to compare to the 80 ele array.. I have lots of tubing that is the
> same size as the current boom so extending isn't an issue. I'm really weak
> on how to feed such an antenna,.
>
> Currently it has a  Folded di-poles as the driven elements such as the
> Cushcraft  738XB does seen here
>
> http://www.cushcraft.com/support/pdf/738xb.pdf
>
> But the elements are mounted through the center of the boom much like the
> M2 Yagis are.
>
> I have *lots* of Cushcraft elements ( 96 to be exact) with the M type
> bracket for the elements they use for Yagis and was thinking of using this
> feed set up and building a LONG BOOM yagi with about ohhhh lets say  28-32
> elements .
>
> The Cushcraft  729B boomer
>
> http://www.cushcraft.com/support/pdf/951456.pdf
>
> uses a  T-Match as the driven element. . Is there a reason for switching
> from a T-Match to a Folded di-pole feed on these antennas ?
>
> My plans are to use one of the folded di-pole directors and use the M-type
> mounting brackets on top of the boom and build something in the area of
> 28-32 ele yagi.  This should give me about 17 db I guess..If I can feed it
> this way.  If if all goes well build another out of the other driven
> element and stack them for a total of 56-64 ele mounted at 50 feet. Since
I
> only have 12 watts on 432 I need all the gain I can get. Antennas are
> cheaper for me as I have lots of parts. And amps cost cash.. I'm looking
at
> getting in the area of 20-22 db if I can for the  432 playground
>
> Comments ?
>
> Dave
> N5ITO
> http://david.davidv.net  <-- My shack
>
>
>
> David L. Vondrasek
> N5ITO Amateur Radio Call
> AAR6NM Army MARS Call
>
>
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> VHFcontesting at contesting.com
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