[TowerTalk] phased array vs. purely parasitic

w8ji.tom w8ji.tom@MCIONE.com
Fri, 06 Nov 1998 21:29:45 -0500

Hi Lane,

> I ran across an article by W6PU regarding a four element phased quad. He
> a pair of loops spaced 1/8 wave and fed 135 degrees out of phase. He then
> added a parasitic reflector and director. Claims that it performs much
> better than the original version of parasitic elements only. Around 5.5
> better.

PU!  Those gain claims smell funny.
(Sorry, couldn't resist the pun.)
> If this is so good why are not others running this set up? I do not have
> modeling software so I cannot do the modeling but is it really 5 dB or
> better than a conventionally fed parasitic array??

That claim is ridiculous.

Yagi's and quads with parasitic elements are very close to optimized arrays
for gain. 

Since PU used a bi-directional cell for a "driven element", he would gain
very little if anything over a regular three element quad from the
additional element. 5.5 dB gain would require an extreme amount of
additional "focusing" in the forward lobe, and it just isn't going to
happen. He'd be lucky if he picked up a fraction of a dB!

73 Tom

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