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I have need of a directional antenna for a 30 foot path within the house.
(the microwave oven wipes out the signal).

Yikes! I have never seen that. I would be concerned about leakage.
Sometimes I have torn into things and found stupid stuff like paint over
grounding surfaces or rust in the compartment. There is a critical ground
around the probe entrance.

My microwave oven is in the far corner of the house and I run 100 watts on
VHF and 600 on HF at times and never had trouble. I never tried the laptop
in the kitchen for fear of spillage. The Linksys is essentially on the
floor to keep people in the park next door from ripping up my bandwidth.
(although sometimes I would prefer geeks hanging out there to chase the rest
out) No coverage problems at all. I do have an HT that gets "some"
interference when I set it on top of the oven.