Wow! Check THIS out!
Maybe my antenna limitations
are not all that serious after all!
I found a thread at eHAM.net forum
about BALCONY attenna issues
and this guy gave a URL to his full tech sheet
on how to build a portable tunable dipole good for FOUR bands!
Here is a sketchy description and below that I have given the URL to the whole article.
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I use a 20-meter dipole that has switches inserted in the right places so I can make it work on 20-, 17-, 15-, 12-, and 10-meters. I also have clip-on torroid loading coils for 30- and 40-meters (they clip across the 10-meter switch to effectively center-load each arm of the dipole). I place the feed on the center of the balcony railing, and extend the dipole up to the upper corners of the balcony, then let the ends drop straight down (sort of like an "M" configuration). Anyway, this works great and is very difficult to see. And the dipole length is constant (band changing by flipping switches only).
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Here is the link to the full article:
http://www.ad5x.com/images/Articles/Dipole RevA.pdf
His posting was at:
http://www.eham.net/forums/AntennaRestrictions/4973
and his profile (for the sake of giving him credit)
is:
http://www.eham.net/user/profile/AD5X