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Author Topic: Could it be the cable?  (Read 7854 times)

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Offline EV607797

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Could it be the cable?
« on: August 26, 2014, 09:45:04 AM »
We just did an installation that involved 36 runs of RG6 type cable for TVs.  Comcast came in and put a converter in that converts the digital signal to analog so that each TV does not require one of their cable boxes.  Everything was working fine until the customer decided that they wanted more channels.  Comcast changed out their equipment and now they're saying that channels 7-24 aren't working.  Everything below 7 and above 24 works.

Normally, this would be a no-brainer and I'd toss it back at Comcast, but the customer says it isn't happening at every location. 

Could an issue with the cable runs cause something like this?  Remember, this is analog TV.
Ed Vaughn

(540) 623-7100 (V)  (910) 835-3600 (F)
EMVaughn3@Outlook.com

Offline jknichols

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Re: Could it be the cable?
« Reply #1 on: August 26, 2014, 11:18:05 AM »
Wow, sounds like some kind of notch-filter.
If they had only 2-14, I'd check that the affected TVs were set to Antenna instead of Cable.
Channels 14-22 are in the FM Radio band between 6 and 7, so I could see that block filtered out, but 7-24 is a mystery to me.
I would think that cable damage / kinking would cause a loss of high frequencies, not a notch.

How do the 36 runs connect to Comcast's equipment, individually, or one output from Comcast to your amplified splitter?

Offline EV607797

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Re: Could it be the cable?
« Reply #2 on: August 26, 2014, 11:25:10 AM »
Comcast installed seven 9-port splitters.  Each of these splitters' inputs is fed from another 9-port splitter that ultimately feeds from their digital/analog converter.  They put terminating resistors on all unused ports.  We just put connectors on our cables and terminated them on these splitters.
Ed Vaughn

(540) 623-7100 (V)  (910) 835-3600 (F)
EMVaughn3@Outlook.com

Online MacGyver

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Re: Could it be the cable?
« Reply #3 on: August 26, 2014, 11:45:35 AM »
Each of these splitters' inputs is fed from another 9-port splitter that ultimately feeds from their digital/analog converter. 

Remember the math behind your db conversions.  I can't say for sure that's the problem, but no tech worth his salt would ever daisy chain splitters.  Is that what you meant, or is there a single 9 port splitter that in turn feeds each of the other 9 port splitter one step down from it?  Also you said it's not all locations.  Is it possible they're isolated to specific splitters?

7-24 encompasses two totally different areas.  The picture and sound carrier for 7 in the 175MHz range where the picture and sound for 24 is all the way up at 530 MHz.  Now the frequency for channel 6 however drops significantly.  As Jknichols said, 7 gets you down from the 175 range to the 83 MHz range, and the wavelength changes signicantly from about 67 to 142.

Assuming the splitters are daisy chained, could someone have caused a ground in the crimp????

If it were me, I think I'd take my pocket tv and go to the splitters.
-I'm only here because my flux capacitor is broken.

Offline JWRacedog

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Re: Could it be the cable?
« Reply #4 on: August 26, 2014, 12:36:46 PM »
We just got done running 35 plus runs of RG6 for  8 apartments & 4 businesses.  I'll be looking at this thread carefully.  I hope there is a positive outcome for you on this. 
Retired Now

Offline EV607797

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Re: Could it be the cable?
« Reply #5 on: August 26, 2014, 12:40:06 PM »
Trace, they hit one 9-way splitter with the feed.  Then, in star topology, fed each of the other splitters with an individual cable, so they aren't exactly daisy chained.  I was surprised to see that they did it this way, but who am I to argue with the almighty Comcast?

I do have to wonder if one of their splitters feeding only the affected TVs is causing this.  I guess that shouldn't be very hard to determine.  Most of these TVs are mounted on fitness equipment, so it will be easy to just try hooking up to an adjacent machine's outlet for troubleshooting purposes.  

Yes, this is quad-shield plenum cable, so it is entirely possible that we got a whisker in one of the connectors, or maybe more.  I sure hope that's not the case here.
Ed Vaughn

(540) 623-7100 (V)  (910) 835-3600 (F)
EMVaughn3@Outlook.com

Offline ttech

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Re: Could it be the cable?
« Reply #6 on: August 26, 2014, 02:44:06 PM »
Do you have one of those cheap coax testers? That may help.   

I would also thing that with that many TVs comcast would engineer a solution.

Online MacGyver

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Re: Could it be the cable?
« Reply #7 on: August 26, 2014, 03:34:48 PM »
I would also thing that with that many TVs comcast would engineer a solution.

You would think so.  With a Wavetek meter you can isolate it within 10 minutes.
-I'm only here because my flux capacitor is broken.

Offline ttech

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Re: Could it be the cable?
« Reply #8 on: August 26, 2014, 03:57:15 PM »
How long are the runs.  About 175 feet is all they want to see on an RG6 around here.

Online hbiss

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Re: Could it be the cable?
« Reply #9 on: August 26, 2014, 04:40:30 PM »
Ed, are ALL the TVs affected? NONE get 7-24? What channels did they have before? 2-6?

A related story- I have a customer that is also a health club like this. I was there for a service call for the phones a few weeks ago and the KSU happens to be in the same closet as the cable distribution. I hadn't been there for a couple of years and when I open the door and what I see makes me laugh my ass off. A 6 foot rack that I could just about squeeze by. On the top were two shelves with 12 cable boxes (6 and 6) standing on edge and below are mounted 11 Blonder-Tongue modulators- channels 2-12. Video and audio out from the cable boxes to the mods then combine the outputs to feed the distribution. Because the cable boxes were on end and right next to each other they had a bunch of fans blowing on them to keep them cool. I laughed but except for the fans I guess it's a cheap and dirty solution and if they want some other cable channel just change the channel on one of the boxes.

-Hal
I gotta get out of this business...

COMSYSTEC- Phone Systems | paging systems | background music systems | foreground music systems | retail music | restaurant music

Offline silversam

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Re: Could it be the cable?
« Reply #10 on: August 26, 2014, 07:43:02 PM »
Ed -

I would ID all the cables and see if which splitter they feed from. If It's not something stupid like one bad splitter, I would grab a small TV, put it on a cart and wheel it over to the splitters. See if you're getting everything back at the distribution point.

Somebody mentioned distance. Depending on the runs, you might need an amplifier and/or some RG-11.

I did CNNs studios in Rockefeller Center 10-12 years ago and I had grief from Time Warner. Luckily for me, a video engineering firm had designed the layout and it worked perfectly - Until Time Warner changed something and the picture went to sh*t. The engineer had the tools and pointed TW back to their problem in 15 minutes. HIM they listened to. Me? Not at all.

BTW, that was quite the job. EVERY desk got voice, data and video. About 500 locations and two huge studios -one for Connie Chung and one for Paula Zahn. Studios were on the ground floor and offices were up on the 20th or 30th floor. Big feeders.

And the two anchors? Couldn't have been nicer. No BS, polite, sweet, fun. A pleasure to work for.


Sam

Online hbiss

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Re: Could it be the cable?
« Reply #11 on: August 26, 2014, 08:22:02 PM »
My big question is why the customer is asking you to fix this. The cable company has the equipment to determine in about 2 seconds if there is a signal there or not and they are responsible. I don't have to tell you about trying to troubleshoot without any equipment. Unfortunately I took my, what originally cost $2500 analog signal level meter to the scrap yard a few months ago so I can't help you.

-Hal
I gotta get out of this business...

COMSYSTEC- Phone Systems | paging systems | background music systems | foreground music systems | retail music | restaurant music

Offline EV607797

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Re: Could it be the cable?
« Reply #12 on: August 27, 2014, 07:16:20 AM »
Hal:  No, this isn't happening on all of the TVs, just some of them.  The reason that they are asking us to troubleshoot this is because we ran the cables.  We originally were only supposed to run them and let Comcast terminate them.  Unfortunately, the customer insisted upon plenum cable and Comcast doesn't stock connectors for that, so they refused to do the terminations.  Now that we've done them, they don't want to have anything to do with troubleshooting.
Ed Vaughn

(540) 623-7100 (V)  (910) 835-3600 (F)
EMVaughn3@Outlook.com

Online hbiss

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Re: Could it be the cable?
« Reply #13 on: August 27, 2014, 07:38:27 AM »
Go to the TVs in question, make sure the input is set to cable and push the auto program button and let it run.

-Hal
I gotta get out of this business...

COMSYSTEC- Phone Systems | paging systems | background music systems | foreground music systems | retail music | restaurant music

Offline EV607797

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Re: Could it be the cable?
« Reply #14 on: August 28, 2014, 10:17:57 PM »
We went to the site today and found that the missing channels (7-24) affect all of the TVs, not just the ones that are built into the fitness equipment.  I could understand the possibility that a faulty cable or two, or even a bad splitter could be causing this issue for a few of them.  The fact that ALL of the TVs are demonstrating this proves to me that our cabling and terminations aren't the cause.

All channels below 7 and above 24 come through just fine.

We will be going there next week with our own TV and connect it directly to the cable head. There is an open port on the tap, so this should be a hands-down demonstration to the customer. After a full auto channel scan, we should be able to prove where the fault lies.

The proverbial guilty before being proven innocent.......
Ed Vaughn

(540) 623-7100 (V)  (910) 835-3600 (F)
EMVaughn3@Outlook.com

Offline silversam

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Re: Could it be the cable?
« Reply #15 on: August 29, 2014, 08:07:50 AM »
Good catch, Ed.

Make sure you bill for all your visits and time.

Sam

Offline tonyburkhart

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Re: Could it be the cable?
« Reply #16 on: September 08, 2014, 08:18:20 AM »
Any updates? I'm in suspense :)
Thanks,
Tony Burkhart
Team Burkhart
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Offline EV607797

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Re: Could it be the cable?
« Reply #17 on: September 08, 2014, 01:49:57 PM »
We took a 13" portable TV out there and connected directly to an open port on the Comcast tap.  Set up the TV to auto tune and it picked up every channel just fine.

Connected to a spare port on one of the splitters and same thing:  Every channel came through just fine.

Went upstairs and spot-checked the floor outlets for the fitness equipment.  After checking about ten of them with the same results, we realized that there was nothing wrong with our cabling.

Upon further investigation, we found that they have two brands/models of multimedia centers on the fitness equipment.  All were auto-tuned to the original cable channel lineup when they were installed.  The vendor of these systems claimed that they reconfigured them remotely and that roughly half of them didn't receive the additional channels afterward.  Of course, they didn't send anyone out to confirm this; just insisted that they did their part and now we needed to do ours.

In the end, there were about a dozen TVs that needed to be reconfigured manually.  That's all that it ever was from the beginning, but as always, the lowly cable installer is the one who caused the problem.  $450.00 worth of troubleshooting time later, the customer is happy with us and NOT happy with the fitness equipment provider.  Par for the course.

As always, thanks to everyone for the suggestions and commentary.
Ed Vaughn

(540) 623-7100 (V)  (910) 835-3600 (F)
EMVaughn3@Outlook.com

Offline tonyburkhart

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Re: Could it be the cable?
« Reply #18 on: September 08, 2014, 02:05:44 PM »
Classic. Absolutely classic.

Cool deal, thanks for the update. We could almost "call the shot" on these ones :)
Thanks,
Tony Burkhart
Team Burkhart
www.teamburkhart.com