TVs & Home Theaters forum

General discussion

Is HD Cable signal strength dependent?

by 45921 / August 19, 2006 6:43 AM PDT

Unfortunately, the home I moved into is wired for cable via a maze of splits and extensions. The room in which I watch the most TV is at the end of the line after many splits.

In this room, I often don't get many of the features I should on digital cable -- the OnDemand works intermittently, and even some channels don't work. I had to cancel my cable-internet due to poor signal strength. Oddly, things work much better in cool weather compared to hot.

I'm considering a new HD TV, but wonder if its going to be worth the investment -- I'd hate to get the TV home, install the Comcast HD box, and then learn I cannot receive (adequate) HD signal.

Of course, neither comcast service nor a TV salesperson has any intelligent reply to this question.

Does anyone know if HD is signal strength dependent?

(Second question - does anyone have any theory why warm weather would reduce signal strength/increase problems. My theory is that the old copper cable in the wall expands during heat. I get much better service in the winter.)

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by kena10 / August 20, 2006 4:34 AM PDT

And to give you a short answer, yes.

Cable signals are good (in a perfect world), up until they come into your house.

It seems like you have really old coax wires inside your home. Although this is a silly idea, try and see if you can replace some of the lines inside your home with new ones.

Cable signals, especially hd signals, require a certain db level, otherwise you're going to start to experience tiling issues and image degradation.

Sorry to be the bearer of bad news but, at this point I would suggest bringing new lines into the house and do lots of wire fishing.


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by stewart norrie / August 20, 2006 9:24 AM PDT
In reply to: Interesting......

If you are only feeding one t.v. then you may want to just run 1 new co-ax cable from outside to your t.v. Or check out a satellite system dish network or direct t.v they will install the dish system and run a new cable for you. I have had the Dish network hi-def system for 2 years and have never had a problem good luck stewee

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heres some basic info
by gabereyes / August 20, 2006 1:44 PM PDT

Amount of signal loss in your system. In every system, there is some amount of loss from antenna to TV set or FM receiver.

Cable Loss: There is some loss for every foot of cable used, depending on the size of the cable (Bigger cable = smaller loss); the length (longer length = bigger loss); signal frequency (more loss on channel 69 than channel 2).
Splitter Loss: Occurs every time the signal coming from the antenna or cable is split. To operate two TV sets, the two-way splitter used reduces signal 30%; four TV sets, the four-way splitter reduces the signal 60%.
Feed-thru Loss and Isolation Loss: Usually occur in large MATV systems (motels, apartment buildings). In 98% of home systems, these losses will not occur.

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Have the cable company check strength
by Dan Filice / August 20, 2006 3:04 PM PDT

When I decided to get digital and HD cable service, the cable guy came out and he had a meter that measured the signal strength at the end of the various cable ends. He said that HD requires a certain signal strength. So my suggestion would be to call the cable company and complain about not receiving signal, and they should send someone with a signal strength meter. Don't try to solve this yourself. As far as summer vs winter, could it be that more people are watching the cable service during summer, thus causing an overload at the cable distribution source? Probably not, but it sounded good.

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follow up
by 45921 / August 20, 2006 4:07 PM PDT

thanks to all for the advice

I coincidentally did what the most recent poster suggested - I've called the cable company, and they're sending someone out to test signal strength.

Fishing new wires is not an option - I wish it was. Nor is a new line, or a satellite dish, due to condo complex configuration.

Interesting fact I learned from Comcast -- old copper coax -- like anything -- expands with heat. They told me its very common to receive lower signal strength and resultant problems during warm months. They told me the recent 110+ heatwave we had here in CA, their phones were insane: everyone had service problems.

I'll have to wait and see what the signal strength test shows - and whether a new signal amplifier can help.

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FYI,,, about copper.
by jcrobso / August 21, 2006 7:26 AM PDT
In reply to: follow up

Most metals the resistance in ohms increases with tempture. This increase in resistance will reduce the signal level over long distances. This is life.
Putting a RF amp in the right place will help. John

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And the CableGuy said.....
by 45921 / August 25, 2006 12:48 PM PDT
In reply to: follow up

Had a comcast cable guy out to my place to test signal strength.

He said the signal strength itself is fine. He said the amplifier installed 6 years ago is fine, working, etc.

According to the guy, HD cable signal works on the same ''bandwith'' of the cable as the digital signal -- whatever my experience with digital, I should have similar performance with HD. In my case, since most of digital works, most of HD will work. I may experience occassional tiling as I do now.

His assessment - its the poor quality of the old cable in my walls, and maybe some low quality splitters (one is in a 100% inaccessible location due to home modifications.)It's not the signal.

His advice - go get the HD box from Comcast and test it out for a while. While I won't get the widescreen, I will at least see if the signal on the few HD channels works. It won't be HD on a regular TV, but at least I'll know if it works at all. If it works - OK to buy an HD TV. If it doesn't work, return for a non-HD, digital box.

The other thing I didn't realize is how few HD channels there are - just the major networks, PBS, Discovery, premium movie channels (to which I don't subscribe,) and 1 sports channel. While more are planned long-term, he wasn't aware of any new channels planned for the next year or two (although a service tech may not be the best source of this info.)

I wish there was a way to pull new cable through walls - but all inquiries tell me they cannot do that.

And, I may just go purchase an HDTV set anyway.

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Best Solution In My Opinion
by hireup / August 21, 2006 2:06 AM PDT

Dump cable and get Direct TV. I got sick and tired of quality issues with cable and installed Direct TV. Couldn't be happier. AND a big plus, ALL stress ALL of the channels are digital where as cable is mostly analog. That means that when it's not an HD channel you get a higher quality picture and sound. The only viable alternative to cable is Verizon's FIOS, fiber optic service. Hope this opinion helps

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one more idea please dont laugh
by stewart norrie / August 21, 2006 4:21 AM PDT

My mobil home looks like a police station ha ha 2 dishes 40ft. huge outside antenna and f.m antenna, Well rite down the street there is a huge condo complex and on almost every balcony you can see a dish installed on a stand we are all wired for comcast but as you can see no one wants cable Also after they hooked uo comcast to my mobil home I called and asked if they would switch on comcast for a day so I could see if it worked as well as my dish system. they did and talk about picture problems most s.d. and hi-def channels looked horrible Just an Idea. Dish also has a cover for the dish that looks like a big rock reallly good luck stewee no joke

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by kena10 / August 23, 2006 3:50 AM PDT

Did you guys read the part where he said that he owned a condo and satellite in his condo was not an option????

Besides, it's not a question of service, it's a question of hardware that is creating the problem (in this case the coax lines inside the condo).

The only option I see viable as of now is to have the cable company run new coax lines along the baseboards of the condo. That's what they usually do in apartment complexes when they want to bring in additional coax lines into other rooms.


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Cable vs satellite
by Dan Filice / August 21, 2006 6:45 AM PDT

What's the difference of signals if you have "digital" cable service as compared to satellite's "digital" signal. They both start out as the same lousy source and then are converted to digital. Just because a satellite transfers the signal doesn't make it better. For a quality signal, a lot depends on how much compression each provider needs to do. I've seen satellite that looks horrible (blocky) because of so much compression, but I've seen the same on cable. Now, if the homeowner here needs to have TV reception provided into different rooms (I have 5 TVs fed a signal), it seems that cable would be the way to go. A simple splitter from the main cable line will provide a free way of getting signals into 5 rooms. No boxes, no add'l roof-top appliances. And, cable enables you to simply add HD and digital cable service (using a cable box) to select TVs while maintaining simple "free" basic cable to other TVs. My neighbor uses satellite and he wanted to get HD, but the installer told him he couldn't because of large trees blocking the signal. Cutting the tree down wasn't an option. I was in my car dealer waiting for service one day, and it began to rain. The TV went blank with an error message on the screen. The service manager came out and said "We have satellite and it always does this when it rains." Hmmm...not a great sales pitch for satellite. I've never had any reception issues with my cable caused by weather, wind, heat, etc. There are lots of reasons satellite and cable can be better than each other. One isn't necessarily better than the other. A lot depends on individual providers.

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by hireup / August 21, 2006 7:21 AM PDT
In reply to: Cable vs satellite

We ran both Direct TV and Brighthouse cable simultanously. The difference, when you are watching a channel and flip from Dish to Cable is amazing. It blows the minds of people visiting. Your bit about digital not making a difference is very wrong when you can flip between cable and dish - it is very obvious. Further, if you are into audio, forget the analog cable you can't get close the the quality of sound, on the same channel, that you get with digital.


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He is mostly right.
by gabereyes / August 23, 2006 1:46 PM PDT
In reply to: NOT TRUE

cable pulls most the digital channels from the same place so they should look the same. but I cant speak for brighthouse cable, I can for comcast and time warner.

And HD channels on cable do look better then sat do to a higher band width

digital channels only look the same from cable to sat if your using a digital cable box, FYI the first 100 channels are not digital the rest of the channels are digital or digital HD.

I think its a brighthouse thing, we have a little cable company here called unite and there signal looks like crap too, but all there channels are analog.

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All of this is provider dependent.
by jcrobso / August 24, 2006 12:50 AM PDT
In reply to: He is mostly right.

DirectTV and Dish, the signal will be all most the same every where in the country. Cable can be drasticaly different depending on the company.
I had cable for many years, switched to Dish 6 years ago.
For about a week I had both cable and Dish. Dish had a better picure than the cable did, it wasn't Comcast at the time.
YES if a very heavy storm comes through I will lose the Dish signal for a few minuets, but with the cable I had, I could loose it for hours or days!!!
All of my daughters have cable and high speed internet through Comcast. In the Chicago area Comcast seems to be good.
All of this said, Comcast has this special, Cable, highspeed Inet and phone for $33 for a year. Maybe I'll give it a try for year,, If I like it by by Dish,
If I don't like it by by Comcast. John

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Poor cable signal
by GWMKJM / January 23, 2011 3:35 AM PST

Unfortunately, we have the exact same problem as 45921 above. We have had our cable company(Suddenlink) come out 3 times so far. First they said signal from outside box was low & fixed that. Then they said it was still low, don't know what they did on that visit. Third time, they said signal coming into house is good, but splitters and old wiring is causing the problem & suggested a booster/amplifier. My question is, has anyone had experience with amplifier & which coax cable is the best to use? Any help would be greatly appreciated.

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Cable amo
by Dan Filice / January 23, 2011 10:42 AM PST
In reply to: Poor cable signal

I had a cable a mp installed because I have a 5-way splitter and the signal strength was uneven. The amp is inside the house and it's plugged into an outlet. The the cable goes back to the splitter. My cable seems better.

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