RustyShackleford said:
I got a DB4, thinking it would be great - all the transmitters are about 38 miles from
me, more or less in the same location - and my place is not particualrly problematic,
except for the heavily wooded lot.
Anyhow, I'm a little disappointed, especially when leaves are on the trees I do not get
everything without dropouts. I thought of exchnging it for a DB8, but I think it I can
get it mounted higher it should be ok.
Ah-ha! I found my handy antenna comparison link:
http://www.hdtvprimer.com/ANTENNAS/comparing.html (edit: erm, it's not
my site, just a favorite site of mine)
The DB8 looks to get about 2db net gain higher than the DB4 over the entire spectrum. It's also more directional and presumably may ignore bounced signals better.
I also stumbled across a
page describing antenna siting with various problems including trees.
If the antenna is behind a tree, it is in overlapping fields: a weak field that passes through the tree plus a weak field that is diffracted around the tree. Overlapping fields are complicated, with strong spots and weak spots. This will be true even if the tree is not a perfect sphere. If you get a UHF antenna to work behind a tree, you will likely see dropouts when the wind blows because the strong and weak spots will move around as the tree deforms. Even in a good-signal neighborhood it is inadvisable to put a UHF antenna behind a tree.
The farther away a tree is, the less of a problem it is. For far away trees, assume no signal penetrates the tree, and reception will be by diffraction around the tree. Trees block 100% of satellite signals.
My inexpert interpretation of the above tells me getting the antenna above the trees would be best. If you can't, getting a more directional antenna may help, but I'm not sure on that one.
Unfortunately just getting a higher gain antenna won't seem to help you because the issue isn't signal strength but signal diffraction.
Anecdotally my PR4400 which is very similar to the DB4 worked well for signals from Bloomington, about 30 miles away from my apartment with a clear line of sight. So again the trees seem to be a bigger problem than the distance.
The home page of the linked site is a great resource for all sorts of HDTV info:
http://www.hdtvprimer.com/
That siting page says that leaves block all satellite signals, but I had a DirecTV dish lazily mounted on a table on the patio (instead of the roof) and pointed directly through the neighbors tree. Surprisingly it worked even after the leaves came in and did pretty well through most thunderstorms. My anecdotal theory was that precise aiming could compensate for the tree, but the link refutes that. Maybe I was just lucky or had a satellite-friendly tree.
EDIT: I notice you say your wooded lot is the problem. If the surrounding lots aren't wooded you could try burying an antenna cable to a point where there is no tree interference and use a strong amplifier to cover the distance. Going up may be simpler, though. That Solid Signal site probably has some tall pole equipment or maybe even a small tower.