| Author |
Message |
mr_c_monkey
Guest
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 Posted:
Wed Oct 06, 2004 6:00 am Post subject:
Help me debug this CATV reception problem. |
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Hi,
I'm stumped with this problem.
Cable Provider : comcast (digital), east bay area
Problem: Bad reception (confetti/snow) on one set (Sony ~5 yrs old)
Topology: Provider cable enters cable box, then into a 4 way splitter. only
two of the outbound connections are connected. The other two are terminated.
Cable wiring is w/in the walls of the house.
On the upstairs set, the cable is connected to a vcr, then to the tv.
On the downstairs set, the cable goes directly to the tv.
Distance from the cable box to upstairs tv is about 60' walking, no way to
tell the length w/in the walls.
Distance from the cable box to the downstairs tv is about 150' walking.
Observations:
1. I swapped out all cables on upstairs tv. Nothing seemed to help. Even
bypassed the vcr, nothing changed. Maybe they even got worse.
2. I've tried a Radio Shack in line attenuator, and in line amp. No change,
maybe they got worse.
3. I noticed that a few times, when I was messing with the upstairs cabling,
it seemed to affect the down stairs tv, the downstairs tv reception was
worsened.
4. Once I noticed that after one of these debugging sessions, the reception
got really bad so I gave up for the night. The next day, everything was
much improved. (??).
5. On the upstairs tv, the reception is bad, and it's even worse when trying
to watch tv through the vcr. The picture has a rolling horizontal line,
and the vcr seems to flash a blue screen periodically (this I thought was
because the signal was weak, hence the amplifier experiment).
I'm good with software, cars and home construction, but with CATV, my
knowledge is limited.
Thanks for any advice.
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weitrhino
Guest
|
| Posted:
Wed Oct 06, 2004 7:18 am Post subject:
Re: Help me debug this CATV reception problem. |
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"mr_c_monkey" <mr_c_monkey@yahoo.com> wrote in message
news:b58913dc.0410051800.44923ab0@posting.google.com...
| Quote: | Hi,
I'm stumped with this problem.
Cable Provider : comcast (digital), east bay area
Problem: Bad reception (confetti/snow) on one set (Sony ~5 yrs old)
Topology: Provider cable enters cable box, then into a 4 way splitter.
only
two of the outbound connections are connected. The other two are
terminated. |
Replace with a 2 way splitter, reduces signal loss.
| Quote: | Cable wiring is w/in the walls of the house.
On the upstairs set, the cable is connected to a vcr, then to the tv.
On the downstairs set, the cable goes directly to the tv.
Distance from the cable box to upstairs tv is about 60' walking, no
way to
tell the length w/in the walls.
Distance from the cable box to the downstairs tv is about 150'
walking.
Observations:
1. I swapped out all cables on upstairs tv. Nothing seemed to help. Even
bypassed the vcr, nothing changed. Maybe they even got worse.
|
The problem is prior to this point.
| Quote: | 2. I've tried a Radio Shack in line attenuator, and in line amp. No
change,
maybe they got worse.
|
Radio Shack for CATV use is almost always a bad idea.
| Quote: | 3. I noticed that a few times, when I was messing with the upstairs
cabling,
it seemed to affect the down stairs tv, the downstairs tv reception was
worsened.
|
Be certain of the wiring method. Home run or loop through method?
| Quote: | 4. Once I noticed that after one of these debugging sessions, the
reception
got really bad so I gave up for the night. The next day, everything was
much improved. (??).
|
Classic example of a poor connection or damaged cable---somewhere.
| Quote: | 5. On the upstairs tv, the reception is bad, and it's even worse when
trying
to watch tv through the vcr. The picture has a rolling horizontal line,
and the vcr seems to flash a blue screen periodically (this I thought
was
because the signal was weak, hence the amplifier experiment).
|
Blue screen = poor signal power. Rolling horizontal line = ineffective
ground plane or ground loop.
| Quote: | I'm good with software, cars and home construction, but with CATV, my
knowledge is limited.
Thanks for any advice.
|
Best bet: Schedule a service call. Let the guys with the knowledge and the
equipment solve it for you and then educate you.
weitrhino
(16 yr CATV vet) |
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DCT Dictator
Guest
|
| Posted:
Wed Oct 06, 2004 7:51 am Post subject:
Re: Help me debug this CATV reception problem. |
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|
"weitrhino" <weitrhino@spamfree.net> wrote:
| Quote: | 5. On the upstairs tv, the reception is bad, and it's even worse when
trying
to watch tv through the vcr. The picture has a rolling horizontal line,
and the vcr seems to flash a blue screen periodically (this I thought
was
because the signal was weak, hence the amplifier experiment).
Blue screen = poor signal power. Rolling horizontal line = ineffective
ground plane or ground loop.
I'm good with software, cars and home construction, but with CATV, my
knowledge is limited.
Thanks for any advice.
Best bet: Schedule a service call. Let the guys with the knowledge and the
equipment solve it for you and then educate you.
weitrhino
(16 yr CATV vet)
|
I agree about the service call. Sounds to me like bad cable or the
cable has a bad splice someplace.
I would diagnose bad prewires with a 30' piece of RG59, just to bypass
it - like out the window down to the junction box. That often made up
the mind of the customer who would not believe that the wire in the
wall was bad and my only way to repair it was to post-wire the cable.
DD
another cable vet - from the bay area . . ..
--
moblog at http://dctdctator.textamerica.com/ |
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mr_c_monkey
Guest
|
| Posted:
Fri Oct 08, 2004 1:52 am Post subject:
Re: Help me debug this CATV reception problem. |
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|
DCT Dictator <dctdictator@aol.com> wrote in message news:<1lq6m0lhoii4sjnnvsohmtk91oquplp8c7@4ax.com>...
| Quote: | "weitrhino" <weitrhino@spamfree.net> wrote:
5. On the upstairs tv, the reception is bad, and it's even worse when
trying
to watch tv through the vcr. The picture has a rolling horizontal line,
and the vcr seems to flash a blue screen periodically (this I thought
was
because the signal was weak, hence the amplifier experiment).
Blue screen = poor signal power. Rolling horizontal line = ineffective
ground plane or ground loop.
I'm good with software, cars and home construction, but with CATV, my
knowledge is limited.
Thanks for any advice.
Best bet: Schedule a service call. Let the guys with the knowledge and the
equipment solve it for you and then educate you.
weitrhino
(16 yr CATV vet)
I agree about the service call. Sounds to me like bad cable or the
cable has a bad splice someplace.
I would diagnose bad prewires with a 30' piece of RG59, just to bypass
it - like out the window down to the junction box. That often made up
the mind of the customer who would not believe that the wire in the
wall was bad and my only way to repair it was to post-wire the cable.
DD
another cable vet - from the bay area . . ..
|
Thanks for the input.
Answers to some of your questions ..
1. All runs are home runs from the cable box on the side of the house.
2. I'll try bypassing the bad cable with a cable from the cable box directly
to the vcr/tv.
3. If that doesn't fix things, I'll request a service calls.
thanks .. |
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