As a follow-up to my previous post, I finally got the chance to test my Winegard YA-1713 and Antennas Direct 91XG outside for comparing reception against my attic location. In the attic, these antennas, as well as my CM4228, see signals through wood siding and/or plywood roof with asphalt shingles and receive stations up to around 50-55 miles in mid-day conditions. My area is an average suburban neighborhood with fairly flat terrain, homes spaced fairly well apart, some decent-sized trees around, but not a forest, and with no multipath problems at all.
The reason for my testing was that I'm right on the fringe for a 54-mile UHF station with my attic setup, and cannot reliably get stations at 60-65 miles in the daytime, although they do tend to come in later at night. My tv tuner will sense a signal starting at about 33 on the signal stength meter, and will reliably lock over about 37 or so.
I temporarily hoisted the two antennas (individually) outside up to about the height of the top of my chimney. I have four distant VHF stations of interest, one of which I've never gotten (71 miles), another which I've never gotten since they switched back to VHF (62 miles), and two that only occasionally came in late at night (each 65 miles). With the YA-1713, the one station that I've never gotten still didn't come in (perhaps they are not yet up to full power), the one which I've never gotten since they switched back to VHF barely came in at a 35, and the two that only occasionally came in late at night both came in solid at a 64. These last two channels even locked in around 40 when the YA-1713 was only 6 feet above my deck (much lower than the top of the chimney).
For UHF with the 91 XG, I tested a number of distant stations, several of which were in the 60-65 mile range. Some still did not come in at all. For one of my stations (at 68 miles) that only comes in late at night, it registered about a 40 and was stronger than from the attic. Another station at about 45 miles registered around a 60 on the meter, higher than the 48 or so it usually is from the attic. Another station (at 65 miles, and not very powerful) that I've only received once before (late at night) barely registered at a 35 on the meter.
From this, it seems that moving the antennas outside would indeed improve reception somewhat, bumping up my reception range by perhaps 10-15 miles. However, the improvement appeared much more pronounced for VHF than UHF. This also seems to confirm that the reception problems many people are experiencing with stations switching back to VHF are especially true where people are using indoor antennas.
Hope this is helpful to others planning their antenna setups these days...