Stacking Loop Yagi's

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G4OHV
Posts: 37
Joined: Sat Oct 08, 2011 10:31 pm

Stacking Loop Yagi's

Post by G4OHV » Fri Nov 16, 2012 11:34 pm

I am intending to stack 2 X 27 element 23cm Loop Yagi's.
Does anyone know the stacking distance

regards

Col

M0DTS
Posts: 468
Joined: Sun Feb 24, 2008 9:03 pm

Re: Stacking Loop Yagi's

Post by M0DTS » Mon Nov 19, 2012 3:58 pm

Hi Col,

I have two bayed and used 75cm spacing, it is not that critical because i tried various different spacings 50-100cm when i first got them with only a small change in main lobe performance, mainly differing levels of side-lobes.

The larger the spacing the more the gain but at the cost of stronger side lobes...

Related article for VHF yagi stacking etc maybe interesting read: http://www.grantronics.com.au/docs/StkYagis.pdf

Rob
M0DTS

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G8ADM
Posts: 121
Joined: Sat Feb 23, 2008 7:14 pm

Re: Stacking Loop Yagi's

Post by G8ADM » Sun Nov 25, 2012 10:26 pm

Hi

Slightly negative comment from me!
The maximum additional gain you will get from stacking two antennas is +3dB
This assumes no loss in the two way splitter, antennas with an identical impedance, identical feed cables etc.
All this is very unlikely so the best improvement you will get is say +2dB
It's really not worth all the effort. It would probably be worth putting up a stack or box of four but not two.

Regards,

Dave.
G8adm

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