About receiving loop balance, it seems that if I coil up the coax (instead of leaving it in a jumble) then moving the coax around seems to have less of an effect on the reception than when the coax is in a jumble. Perhaps it's acting as some sort of a choke when it's in a coil.
Mom always said, "Neatness counts!" Yes, you're making a choke. A smaller diameter coil, wrapped on a plastic bottle or something, would be even better.
As for VHF/UHF, another way of saying "rubber ducky antenna" is, Dummy Load
. No surprise you aren't hearing much. Because much FM-voice operation is done mobile, vertical polarization is the standard for FM. CW and SSB operators almost always use horizontal polarization. On the VHF/UHF bands, polarization makes a big difference.
The good news is, it's easy to make Yagi antennas for those bands. Mssrs Yagi and Uda, who developed the antenna, were, of course Japanese, so an array of them on your balcony could be talked away as celebrating your host country's rich radio heritage!
If your Yagi isn't going to stay outdoors permanently, you can make it from cheap, lightweight materials. A half-wavelength at 432 MHz is only about 14 inches. You easily can make a Yagi with whopping gain that stashes in a closet when not in use. Gains of 13 dB or more are no problem. Even on 144 MHz, a Yagi only a few feet long is good enough for hundreds of miles with QRP power.
But while you're trying to surmount your HF noise problems, you could try making a two-band dipole. An SO-239 connector with four pieces of solid copper wire (say 14-ga) set up on your tripod will way outperform the ducky. For receiving, you don't have to be compulsive about matching if you have only 15 feet or so of feedline. Use the formula 468/f-MHz to get the dimensions. Download the Japanese bandplan chart: http://www.jarl.or.jp/English/6_Band_Plan/JapaneseAmateurBandplans20090330.pdf
I see that CW is done around 430 MHz there, while U.S. hams operate higher in the band. Our Two-Meter CW bandplans are similar, 144.02-144.10 over there.
Omnidirectional horizontal antennas called "halos," or even horizontal loops are another option, but you can whip up a simple two-band dipole in a few minutes.