Inspired by this discussion, I wanted to check if this is something I can get away with.
I've got an old FM Broadcast antenna that came with a home stereo receiver -- it's 75 ohm flat cable, in a T shape (not sure if it's a loop or folded dipole, but I'll check -- let's assume, for this question, that it's a folded dipole). It's close to resonant length for the 3m approximate center of the FM Broadcast band.
I've read that antennae often work well if they're on a third harmonic of the transmit frequency. This antenna is close to a third harmonic of the upper end of the 10m ham band (a little short, but not much).
I currently have it connected to a Heathkit SB-102; I was using it to test the receive functions. It occurred to me that I might be able to transmit meaningfully (possibly at reduced power) on the highest 10m segment supported by this transceiver (29.5-29.8 MHz), or, if there's enough matching capability, on the rest of 10m band. I'm concerned, however, not to damage anything while trying to adjust the transceiver's matching network.
Is that a realistic concern?