Jim: What kind of metal tube? The kind with wheels?

Well, it did have some. It's an older 12x65 mobilehome, with aluminum siding
and steel roof. The tiedowns, including those over the top, are probably
grounding the mobile, maybe even better than the ground I have in my little
office/shack.

I suspect I'm picking up sigs off the phone and power wiring. In fact, when I
clip onto a grounded wrought iron chandelier in the dining area or bathroom, I
get better signals on all bands, even AM and FM. And 3210 is better on that,
using my eTR7, than my DX-392 gets on the 65-foot outside antenna!

The ground wire is, of course, inductively (or capacitively) coupled to a
mighty long antenna, the area power lines. LOL Of course, there is some noise
on the line sometimes, but I usually win.

My trailer may be antenna -- or a reflector. Sometimes outside, I can hold a
portable close to the alum skin and get better sigs using just the radio's
whip.

73,
Bill, K5BY