[TowerTalk] QUAD : coax switching and 40m..

[Pete Soper]

Hi LB,

You wrote:

> in some distant future issue of Communications Quarterly.  If I owned a
> GEM or Lightning Bolt Quad, I would seriously think about rewiring it for
>separate feed.  If I opted for a Cubex, I would choose the separate feed
>option over the transformer (which apparently is designed to effect some

I'm preparing to assemble a Gem Quad right now. After completing many
modeling runs with EZNEC and straight NEC2 I've abandoned the
manufacturer's specs and am going with a switchbox and 1/4wl 
transformers. No matter how I slice it, Gem Quad's instructions for
tying the feedpoints together results in severe distortion of the 10m
pattern (among other things).

By the way I plugged the wire sizes into my model after the discussion of
RF resistance and it appears that #12 wire vs #18 for the 10 meter band 
elements translates to 1/4db of gain. I'll take it!

Also, the triband quad switchbox design in the ARRL Antenna Book 
is in agreement with you and Paul Ferguson about leaving unselected 
elements open when 1/4wl transformers are used (i.e. effectively 
shorting the feedpoints).

Regards,
Pete
KS4XG

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