[TowerTalk] Crossed Dipoles....

[Tom Rauch]

> The late W2PV wrote an article on crossed dipoles in either QST or CQ in
> the late 70's.   He put them up high (150' or so) and needed a strong
> signal in all directions.  At this height the pattern is very figure 8
> with nulls off the ends.   Several mobile antennas use this concept at
> both HF and VHF.
> 
> You can used crossed dipoles to also work both ends of 80/75, too.  Set
> one on 3800 and one at 3525 for example.

Just remember you need to shift the phase in one dipole 90 
degrees, or you won't have an almost omni pattern.

If you simply parallel the dipoles at the feedpoint with no phase 
shift, the pattern would be just like a single dipole with maximum 
radiation at right angles to a line bisecting the in-phase wires. 

So if you have ends like this from a top view:

A                         B



X                          Z


and A and X tie together at the feedpoint while B and Z tie together 
to the other side of the feedline, the lobe is a regular dipole pattern 
going up and down on this screen.


73, Tom W8JI
w8ji@contesting.com

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