[CDuda]

Ok here is my setup…


- Samsung 56†DLP with Samsung T160 STB

- Channel Master 4228 Antenna with Channel Master 7778 preamp. This is mounted in my garage about 10 feet up

- According to AntennaWeb all of my HD channels are within 4 compass degrees of one another and the CM 4228/CM7778 combo should be more than powerful enough to bring these stations in.


Here is what happened…

- I setup the antenna yesterday afternoon and was able to get the Samsung T160 to scan 10 HD channels. ABC-HD was at 100%.

- 3 minutes into the game I lost the ABC-HD signal. A couple of times the T160 would flash a frame, however the T160 signal strength meter registered 0%.

- I tried to re-scan the channels this time I only got one channel (CBS-HD at 100%). I kept trying this through most of the 1st half of the game (still not ABC-HD).

- After the game was over I tried again. This time I got the 10 channels again (ABC-HD was at 100%).

- I should I also note that occasionally all of the channels experience a momentary signal strength drop (about 20-30%) from time to time, however most of the time the majority of the channels are at 100%.


So what is going on here? Could this be a reception problem (I could move the antenna to the attic – It would be about 15’ higher)? Could this be an antenna alignment problem? Could this be a problem with the CM 7778 preamp? Is this a problem with the Samsung T160 (which I have read may not be the best at handling OTA signals)?


Between the Eagles stinking it up on the field and my HD reception problems last night was a big disappointment.

 

[SteveK2]

Well, this isn't really an issue with local reception, but more likely a hardware issue. You may have better luck posting this in the hardware section of the forum.


Having said that, you didn't mention anything about your exact location. It may be that your signal strength is quite high without the pre-amp and you are experiencing signal overload or possibly multipath. So more precise information about your location (i.e., distance from transmitter) would help here.


Also, have you done any diagnostic work yourself? You ask lots of questions...could it be this, could it be that....the answer is yes, it could be any of those until you try a little process of elimination. For example, regarding the pre-amp....don't use it and see what the result is. Check all of your connectors (did you make them yourself or are they 'factory made' (not that that guarantees that the connections are any good).


Your symptoms sound like they might be multi-path problems, but you need to provide some info and do a little investigating/diagnosing, too.


BTW, I'm in Central NJ (about 48 miles northeast of the Philly transmitters). I use a Samsung Ts-160 STB, a CM 4228 antenna in the attic, and a CM 7775 pre-amp (a very similar setup to you). MNF was rock-solid gorgeous last night....signal strength @100%.


Good Luck

 

[CDuda]

SteveK2,


I live in Northern Chester County (Phoenixville) so that would put me about 15 miles (approx) from the transmitters.


I have done some testing of my setup. When I disconnect the preamp my signal strength drops about 25-30% on all HD channels except for CBS (it is still at 100% - Since CBS and ABC broadcast from the same location I have to assume that CBS is using more power that ABC). My cabling is all RG-6QS with self installed crimp connectors. I have checked each connector (all are sound with no shorts).


I am familar with multipath signal interference with analog TV, however I am not sure how to properly test this and correct with HD sources (or even how it would manifest itself/degrade the digital signal since it is not going to show up as a ghost like in analog reception - for HD wouldn't it be a repetion and inproper ordering of the digital feed).


At the beginning of yesterday's MNF broadcast my signal was fine (100%) and at the end of game it was fine (100%). It was only after 3 minutes into the game that I experinced problems and lost all of my HD channels except for CBS (which was still at 100%).


Wouldn't multipath impact all HD channels from the same location (again CBS and ABC braodcast from the same exact location)? Or is that how the multipath reception problem would manifest itself with and HD source (effectively causuing the STB to cancel out and ignore the entire data stream). If that is the case what is the best way to mitigate this?