Why do my digital signals come and go

[paul27675]

I have tried both an indoor amplified antenna and now an outdoor roof top antenna both with the same effect.
I get good signal strength with both but my signal comes and goes with no pattern. I may watch TV for 45 min.
with great picture but then have the channel pop in and out several times over the next 10 min. then back to
a good picture for a while. There are no airports near by and this is not weather related. It does this on all chanels.
ANY IDEAS?????

[hdtvlabs]

Does it happen to one specific channel or to all channels?
When you do get a good reception,how strong is the signal? what do you see on the signal strength meter?
Try to provide us more details: the zip code, the channel that fades out, the antenna you are using, etc

[paul27675]

It does it on all channels. My signal strength bounces between 7 and 8 out of 10.
The 2 antennas I have tried are a RCA ANT525 indoor amplified and a
radio shack 40" boom 17 element rooftop. I am approx. 31 miles from TV Towers
based on antennaweb.org. There is little difference between the 2 antennas, they both will
hold the picture for a while and then the signal bounces in and out. Could it be I am just on
the fringe of reception? My zip is 27522.
Paul

[hdtvlabs]

The signal strength is the same for both antennas? That would be very surprising. Amplified or not, ANT5250-like antenna can not come close in performance to 17-elements directional yagi. Are you sure your outdoor antenna actually points to the towers?

[paul27675]

I am positive, I even went outside and rotated the rooftop antenna as my wife watched
the signal strength on the TV and we could get as high as 9 bars.
We watched for a while and then it started going in and out. I am using 50' of RG-6 cable
from the antenna directly into the TV. I have a samsung with built in digital tuner.
One other note, my house is surrounded by lots of tall trees and I live somewhat in a valley

[cylinder]

what you are experiencing is the cliff effect, the main downside to the digital transition.
its basically this: either you get a perfect signal or dont get a signal at all. if you live in a valley, then that might explain it. is the screen completly blank? or is the picture garbled in pixels?

[paul27675]

It is either there or not. When it is there, the picture is great with no pixels and when it goes
it is just for a few seconds and then back, and it will continue doing this for a while then back
to a good picture.

[SWHouston]

cylinder,
Is the location for the TV well vented ?
I've had some problems that were similar to yours, and found that the unit was overheating.
My problem was, that I couldn't do much about it, except put an extra Cooling Fan in.
Hope this helps.

Have a good Day !
S.W.