Mounting question "under-the-eave"
 

I realize that mounting antenna in clear sky and highest possible is mostly best, like on a rooftop.

However, if there was 2nd best option of mounting "under the eave from hanging rafters," meaning the back of the antenna (eg, HD9032 antenna gives this mounting choice a possibility) is against the side of the house, about 1 feet away, will the house siding attenuate the signal, more so than if it was just clear air to the back of the antenna (assuming the front is aimed with a somewhat clear shot of the towers)?

This website shows how TV signals--both VHF and UHF--propagate near buildings and trees.

As long as the signal from the TV station sees the antenna without going through the eaves, there will be no attenuation.