I'm trying to close out a job that we've done recently. It is a dedicated theater with a projector. Everything is working fine but the cable signal looks terrible. There is ghosting, static and basically an overall bad picture. The picture is bad on every TV in the house but is more noticeable because it is a large projected image. We've taken a straight cable feed that comes into the house and sent it to the digital HD cable box in our system and still have the same problem. We also tried a different coax to the box and then went to a vcr to bypass the cable box. The channel amp that we always use, and have been happy with, didn't do anything. Basically we have determent that the cable feed to the house is no good. We don't have a meter that can give us the db rating that the feed is coming in at. We are going to have the cable company come to take a look at the signal.
I was just wondering, since I have no faith in the cable company, what I may be able to do to fix there signal. I'm going to go back over there and try removing the ground from everything connected to our system to see if it is possibly an electrical problem. Would a scalar or line doublers improve the signal even if it does not have something descent to start with?

Thanks for any info

Crap in, Crap out.... Scaler will only increase the problem.

The fact that you say theres ghosting onthe Digital channels is pretty alarming though..... This should be immposible. These are Mpeg encoded digital signals.. They are there, or they are not. (Of course, bypassing the cable box you would have no access to the digital channels through a VCR.. So I doubt that they were checked in that regard)

Definatly sounds like a Feed problem. and a trip from the cable company is in order. A Signal meter is a truely worthwhile investment now-adays. We just upgraded to the Sencore meter and its awesome and really wasnt all that expensive..... COmes in handy for tuning HD Terrestrial broadcasts too.........

I have to disagree with Impaqt's statement above. When reception is marginal on a digital channel, it can capture for 50-100ms, and then lose signal for about that same time. This can result in dropped frames and audio, and some strange effects. I've seen links so marginal that I get blocky blobs of color on screen that move around, while the audio cuts in and out. I something that looks like ghosting possible... I haven't seen it, but I wouldn't rule it out.

Unfortunately, I think you'll have to rely on the cable company. They should be able to come in and crank up the signal level from their amp at the street to make the customer amp unnecessary. (I usually find this to be the best solution, their amps tend to have very good noise figures, and usually they can give me a better signal than I can get using reasonably priced amplifiers.)

Ghosting occurs when ANALOG signals arive at an ANTENNA on multiple paths and time frames. Common in big cities, and in areas where there are multiple obstructions to the analig signal. THis is IMMPOSIBLE with a digital signal.

There can be other problems as you've described. Audio hiccups and the blocking effect thats so common on DirecTV during rain. THos are NOT ghosting. they are interuptions inthe digital signal.

Digital Cable channels use the same technology DirecTV uses(But usualy more compression)

Cable company is your only option. They are required to give you more than just a decent dB level. They are also required to give you decent noise critera rating. I forget what it's called in the industry but there is definately a test that they car run that goes far deeper than just dB rating. Please don't go disconnecting grounds. Putting an isolation transformer on the cable feed for the home theater is always a good idea for controlling ground loops but randomly liftng grounds is asking for trouble.

if you looked at it as soon as it comes in the house and it looks bad, then the only ones that can do anything is the cable company. On the other hand make sure that you are testing it where it comes into the house or even outside depending on the set-up to make sure there are no splitters or amps that are causing the problem

Always remember, the service provider is responsible for the quality of the service to the homes demarc (gray box on the house) and after that it is the responsibility of the home owner. So when in doubt, make the service provider work for that dollar. :) give them a call first thing.

if you want to know if the signal is crap coming in, take your amp and an extention chord (I say this if you don't have a neat RF measuring tool) and hook it up at the service location. If the signal clears up some, then it may just be the wire length in the house. It could also be in part caused by the person who prewired the house pulling a Tarzan with the cable as he pulled it.

In the anycase, if your amp doesn't work in the pannel, just for shits and grins, put it outside... to test... Then if that doesn't work call the catv company..

I say this because in my area (san antonio), Time Warner is a huge pain the ass to deal with, whether they have a responsibility to the clients or not...

I know that when I do an install, my clients call me before they call time warner

Gerald

how do you do that?

You might want to check the terminated end outside for dielectric coating the pin. I have seen this happen before.

The customer had cable co out to her house three times and they couldn't find the problem.

I told her no gaurentees as I started the job with the outside connection. 10 minutes later the problem was fixed. I took my needlenose pliers and gently scraped the dielectric off the RG11's pin and was done.