[50mhz] 5 over 5 stacking recommendations

[jeremy-ca]

That 5/8 spacing has been around since the late 40's when first used on the 
Twin 5 2M array fed with TV twin lead. Performance is OK for short boom 
antennas but not so good once boom length gets over 13-15' or so. Another 
way to feed instead of transposing feed points is to simply flip one of the 
beams over; it still requires 2 unequal length coaxes. I used to do mountain 
topping in VT in the 60's with a pair of Hi Par 3 el Hilltoppers; gave many 
a new state with a rather haywire SSB station when AM still was the norm on 
6M..

Carl
KM1H
On 6M since 1958



----- Original Message ----- 
From: "Ray Brown" <kb0stn at sbcglobal.net>
To: "WD0T" <wd0t at mncomm.com>; <50mhz at mailman.qth.net>
Sent: Sunday, May 06, 2007 10:48 PM
Subject: Re: [50mhz] 5 over 5 stacking recommendations


> ----- Original Message ----- 
> From: "WD0T" <wd0t at mncomm.com>
> To: <50mhz at mailman.qth.net>
> Sent: Saturday, May 05, 2007 8:44 PM
> Subject: [50mhz] 5 over 5 stacking recommendations
>
>
> Greetings all, first time posting here!
>
> I have a question on recommended stack spacing, for using 2 cushcraft 5 
> element 6m yagis, looking to put 2 up on a short crank up
> tower for the June VHF contest.  By short tower I mean a 30ft to the lower 
> 6m antenna. I am talking about stacking one above the
> other.
>
> What would you recommend for stack spacing using 2 of the CC 5 element, 
> stock standard yagis?  Max gain would be nice, but also I
> need to not get crazy in terms of spacing distance.  I have seen in some 
> places recommendations for .6 wavelength spacing for lower
> sidelobes, however I have also read that each type of antenna and height 
> needs to be modeled to arrive at optimum spacing.
>
>
>
>  Howdy! Glad to see a question that I can answer! :-)
>
>  What I have at home is a pair of MFJ-1762 3-element 6m beams, in phase.
> Their manual gives instructions on how to construct a harness that can be 
> used
> to feed the two antennas. The major trick is to space them 5/8 wave, or 
> about
> 11'6" apart, then make sure you attach the center of one coax to the right 
> side
> of the driven element (ground to the other side), while connecting the 
> center of
> the other coax to the left side of the driven element on the other 
> antenna.
> The instructions here are pretty clear...
>
> http://www.mfjenterprises.com/man/pdf/MFJ-1762.pdf
>
>  Good luck!
>
>                _Ray_        KBØSTN
>
>
> Moderator: Ray Brown, KB0STN
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