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Topband: Phasing Flag antennas?

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Subject: Topband: Phasing Flag antennas?
From: (Tom Rauch)
Date: Fri, 19 Nov 1999 10:03:31 -0500
All arrays of antennas increase directivity by a process we used to 
call "pattern multiplication". 

If you look at the pattern you get from that broadside spacing with 
two non-directional antennas, and multiply that by the original 
pattern of each antenna, the result is the new pattern.

We used to have to do that before computers.

>  I'll be putting the second Flag broadside, maximum
> spacing is 150 to 200 feet. I'll be looking from 540khz 
> to topband.

If you look at the broadside pattern of a pair of radiators 150-200 
apart, you'll see the directivity change is minimal. The EWE 
already has a side lobe suppression, and you are adding just 
slightly more suppression. You would get much more side 
suppression (almost infinite) if you stacked them in-line with a 
similar spacing and fed the out-of-phase.

200 feet is just way too close for side lobe null on 160 meters and 
lower to be really useful. It actually takes over 300 feet spacing to 
improve things on 160 if the antennas are broadside, unless the 
individual elements have no side suppression at all!

End-fire is much more space economical, if you can manage it, for 
gain advantage in small area arrays.

> The MFJ-1026 is used to null noise, will it phase my 
> antennas and sharpen the lobe?

Only if the antennas are located correctly for the direction and 
distance of the noise. 
>  Do I aim the two antennas in the same direction?

Yes, as a general rule.

Your other questions are too complex for this forum.
73, Tom W8JI

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