David wrote:


Unfortunately, DTV signals are line-of-sight so anything from a
building near the Tx tower ten miles from you or the woods, trees,
hills, general terrain, etc., can make a weak signal fluctuate. It's
normal to lose reception during storms, snow, rain or even high
humidity in some cases. The higher the channel frequency (not the
channel number you receive on), the worse the symptoms will be.
We're in a fringe area and have an 80 dBm amp running in order to
get anything to come in and you should see how bad it gets here!
Digital has a considerably shorter reception range than the old analog
signals. Our gummint critters are work.

Twayne
A few comments: DTV signals are no more 'line of sight' than analog
signals were. The degree of loss from not being 'line of sight' depends
solely upon the RF transmit frequency rather than if the modulation is
analog or digital. DTV signals do suffer more from dynamic multipath
reception however.

What is an 80 dBm amp? Is that the same as (80-30) dB?

David


I bought 30 feet of cable to try my antenna at various indoor and
outdoor locations. I bought an amplifier because it would have been a
good idea with UHF analog using that much cable. I never tried the amp
because I discovered I could get all the channels indoors on the ground
floor that I could get outdoors 30 feet above the ground. That
convinced me that a few dB of gain wasn't important with HDTV.

One station 80 miles away would break up in some weather conditions.
Reception improved if I turned the antenna 90 degrees from the
transmitter. That must have reduced my gain by a lot of dB. I wouldn't
have received anything at all with UHV analog, but digital worked.

I think multipath distortion from a reflection off the sky was causing
the breakup. I don't know how turning the antenna helped. I was
unaware of that kind of distortion with analog TV, perhaps because the
ghost image was offset by only a millimeter or so.

I'm on a hill. My BIL is in a hole three miles from me. When we both
had rooftop antennas, my reception was better than his. He couldn't get
analog reception after he took his antenna down. He watched recorded
movies.

I told him to try HDTV indoors. He had a cable and a 4-bay bowtie
antenna. He paid $6 for the only balun available at Radio Shack. He
couldn't get any channels, but when I unscrewed the balun and put my
finger on the center conductor of the cable, he received some channels.
Apparently that balun was causing reflections what would have been
acceptable with analog TV.

I gave him a 25-cent balun and he was in business. He gets most of my
channels and some I don't get, down in a hole with his antenna indoors,
80 miles from some of the transmitters. I doubt he has line-of-sight
reception on any channel.