Poor reception for some HDTV channels (ABC, PBS)
 

I have only basic cable but I can receive network HDTV. The problem is that
my HDTV tuner have problems to lock signals from ABC(720p) and PBS(1080i).
Other stations (CBS, NBC, Fox, CW) are ALWAYS great.

My setup is that I immediately amplify the cable signal once it is in my
house. There are four ports out from the Radio Shack amplifier, I use them
to feed my HDTV, VCR, DVD recorder and computer. The other three devices
besides the HDTV are using only analog signals. They all work great. On the
other hand, while watching ABC or PBS program, my HDTV will suddenly drop
the signals and have a blank screen. The temporary solution is odd. If I
re-arrange how all those cables cross and slightly move around all the
cables from the amplifier, I will get my HDTV back on the screen. But like I
am a "giant antenna", if I leave the area and stop touch the cables, most
likely I will lose the signals again unless I find a "rare good spot". After
finding a good spot, it may works for days or only 10 minutes.

This is driving me crazy. Does anyone have a good idea what causes the
problem and suggest a solution? Thanks.

Ar Q

Poor reception for some HDTV channels (ABC, PBS)
 

Ar Q wrote:
I have only basic cable but I can receive network HDTV. The problem is that
my HDTV tuner have problems to lock signals from ABC(720p) and PBS(1080i).
Other stations (CBS, NBC, Fox, CW) are ALWAYS great.

My setup is that I immediately amplify the cable signal once it is in my
house. There are four ports out from the Radio Shack amplifier, I use them
to feed my HDTV, VCR, DVD recorder and computer. The other three devices
besides the HDTV are using only analog signals. They all work great. On the
other hand, while watching ABC or PBS program, my HDTV will suddenly drop
the signals and have a blank screen. The temporary solution is odd. If I
re-arrange how all those cables cross and slightly move around all the
cables from the amplifier, I will get my HDTV back on the screen. But like I
am a "giant antenna", if I leave the area and stop touch the cables, most
likely I will lose the signals again unless I find a "rare good spot". After
finding a good spot, it may works for days or only 10 minutes.

This is driving me crazy. Does anyone have a good idea what causes the
problem and suggest a solution? Thanks.

Ar Q

What is your zip code and what antenna are you using? Where is the
antenna located - indoors, upstairs, attic, outdoors on the roof? The
dropouts come from marginal signal levels which you are splitting
through a cheap Radio Shack amplifier. If you have an inadequate
antenna, the better path is to upgrade the antenna and then, if still
necessary, to upgrade the amp.

Alan F

Poor reception for some HDTV channels (ABC, PBS)
 

On Sat, 07 Jul 2007 16:43:54 GMT, "Ar Q"
wrote:

This is driving me crazy. Does anyone have a good idea what causes the
problem and suggest a solution? Thanks.

Is the distributor/amp equipment-grounded? A lot of this stuff seems
to suggest it be mechanically grounded as well as electrically Might
be something. That four-port Radio Shack amp is not really meant as a
simple distributor, try replacing it with a passive 4-way splitter, or
driving all four of your devices from one output via splitter, you may
have TOO MUCH signal. Or slap on an attenuator or a filter or
something to get the same effect.

J.

Poor reception for some HDTV channels (ABC, PBS)
 

"Alan F" wrote in message
news:[email protected]


What is your zip code and what antenna are you using? Where is the
antenna located - indoors, upstairs, attic, outdoors on the roof?

It is Camcast Cable in Pittsburgh. No antenna.

Ar Q

Poor reception for some HDTV channels (ABC, PBS)
 

Ar Q wrote:
"Alan F" wrote in message
news:[email protected]

What is your zip code and what antenna are you using? Where is the
antenna located - indoors, upstairs, attic, outdoors on the roof?

It is Camcast Cable in Pittsburgh. No antenna.

Ar Q

My mistake. I scanned your posting thinking this was an over the air
reception question. You should try a 4 way simple splitter without the
amp or call Comcast to ask for a service call. The tech may be able to
boost the signal going into the house or remove unused splitters up the
line that are weakening the signal. You are paying Comcast for the
channels, so have them take a look.

Alan F

Poor reception for some HDTV channels (ABC, PBS)
 

"JXStern" wrote in message
...
On Sat, 07 Jul 2007 16:43:54 GMT, "Ar Q"
wrote:

This is driving me crazy. Does anyone have a good idea what causes the
problem and suggest a solution? Thanks.

Is the distributor/amp equipment-grounded?

The Radio Shack amplifier has only 2 pin AC plug. It has not the third
ground pin. I have to remove the third pin if it has one because all of my
A/V equipments are connected. To avoid multi-grounding problem, all 3 pin AC
plugs are using 3-pin-to-2- pin adaptor before plugging into wall outlets.
The whole A/V system are grounded via the cable from Comcast Cable TV.

Ar Q

Poor reception for some HDTV channels (ABC, PBS)
 

"Ar Q" wrote in message
ink.net...
I have only basic cable but I can receive network HDTV. The problem is
that
my HDTV tuner have problems to lock signals from ABC(720p) and PBS(1080i).
Other stations (CBS, NBC, Fox, CW) are ALWAYS great.

My setup is that I immediately amplify the cable signal once it is in my
house. There are four ports out from the Radio Shack amplifier, I use them
to feed my HDTV, VCR, DVD recorder and computer. The other three devices
besides the HDTV are using only analog signals. They all work great. On
the
other hand, while watching ABC or PBS program, my HDTV will suddenly drop
the signals and have a blank screen. The temporary solution is odd. If I
re-arrange how all those cables cross and slightly move around all the
cables from the amplifier, I will get my HDTV back on the screen. But like
I
am a "giant antenna", if I leave the area and stop touch the cables, most
likely I will lose the signals again unless I find a "rare good spot".
After
finding a good spot, it may works for days or only 10 minutes.

This is driving me crazy. Does anyone have a good idea what causes the
problem and suggest a solution? Thanks.

Ar Q


I'm using a RS amp and a 4 tap splitter to power 4 devices. Works well.

Sounds like a bad cable or more likely connection. I've had problems in
other situations when the cable center conductor was just long enough to
touch the conductor in the jack but not make good enough contact. Strip the
cable so the center conductors are long enough and make sure the outside of
the connectors are crimped tightly to the outside conductor. If that's not
it switch cables or replace.

Poor reception for some HDTV channels (ABC, PBS)
 

"Alan F" wrote in message
news:[email protected]
You are paying Comcast for the
channels, so have them take a look.


Can't call Comcast. I am only paying for Expanded Basic Cable, not their
expensive Digital Cable. Not that I am cheap, I just don't like to add one
more box next to my TV.

Guess Comcast don't want to run two sets of cables around the city. When I
bought a HDTV, I was surprised to find out my new TV can pick up the digital
channels from major networks and those unscrambled stations (like religious
and shopping channels), even I don't have an external cable box.

Ar Q

Poor reception for some HDTV channels (ABC, PBS)
 

Ar Q wrote:
"Alan F" wrote in message
news:[email protected]
You are paying Comcast for the
channels, so have them take a look.


Can't call Comcast. I am only paying for Expanded Basic Cable, not their
expensive Digital Cable. Not that I am cheap, I just don't like to add one
more box next to my TV.

Guess Comcast don't want to run two sets of cables around the city. When I
bought a HDTV, I was surprised to find out my new TV can pick up the digital
channels from major networks and those unscrambled stations (like religious
and shopping channels), even I don't have an external cable box.

Ar Q

I'm not sure how Comcast's billing structure works, but the digital HD
& SD versions of the local broadcast stations are provided as
unscrambled QAM channels as part of the basic package. All the cable
companies that provide local broadcast stations on the digital tier are
required to sent them unscrambled. Now the Comcast CSR is likely to have
no clue whatever that you can get the digital locals without a STB
leased from Comcast, but you are legally getting those channels. Ask for
a service call, just don't get into details with the CSR as they usually
know very little.

Of course, you realize that by not subscribing to the digital cable
package and getting a STB, you are missing out on a lot of HD
programming from the national HD cable channels and HD VOD. By this
fall, the number of national HD channels are going to grow quickly,
although Comcast will take time to add them as they have to upgrade
their systems first. Besides, in Chicago, Comcast recently did away with
analog cable except for only the local broadcast stations. Everyone had
to get a digital STB or have a TV / STB / DVR with cable card if they
wanted to still get CNN, TNT, TBS, USA, etc. This will happen to other
Comcast areas over the next year or two. The separate digital tier
package will go away as it will be all digital.

Alan F

Poor reception for some HDTV channels (ABC, PBS)
 

Explain (again, sorry if I missed it) what you mean by "poor reception" on
some "HDTV channels". Unless you're experiencing pixellation (partial
picture dropout or tearing in little squares), digital reception is either
there 100% or it's not there at all. There's no snow with digital
reception. However, if it *IS* a snowy picture then what you're watching
is not a digital signal (and therefore is absolutely not "HD" TV).

Now, some of the OTA stations are doing bit robbing from the main
(primary) channel to do multicasting. This is where a station will have
multiple sub-channels (for weather, alternate programming, etc). A
standard digital (full bandwidth) tv channel has approx 19.4 mbps of
digital bandwidth although not 100% of this is needed for a decent-looking
HD signal. As long as the station has a good quality digital encoder and
does the right amount of null suppression, they can have the main channel
down to 15 Mbps and still have a darn good looking picture.

However, in those situations where the station may have a first generation
digital encoder or they get a little over-zealous with their bit robbing
to try and carry too many sub-channels (3 or more), your main (HD) channel
will at times begin to look like hell. What happens is a phenomena known
as macroblocking. This is especially noticeable in action sports, i.e.,
football, basketball and auto racing. Macroblocking appears as blurry
pixellation but only during the action scene and is otherwise not visible
and the picture will otherwise look fine until the camera pans quickly or
during the first 1 second following a sudden scene change or you get
another fast action scene. NBC's "Friday Night Lights" frequently has poor
video quality because most of the scenes are shot using a portable
handicam. Some of the MPEG4-compression used with some of the satellite
providers (i.e., DirecTV) looks horrible at times because of compression.
Rather than bit robbing they (the satellite provider) is doing digital
compression to conserve bandwidth. Of course the CATV provider can do the
same thing with similar crappy results, but again it's not poor reception,
rather it's poor PQ (picture quality). Translation: An amplifier is
unlikely to help.



In article . net "Ar Q"
writes:


"Alan F" wrote in message
news:[email protected]


What is your zip code and what antenna are you using? Where is the
antenna located - indoors, upstairs, attic, outdoors on the roof?

It is Camcast Cable in Pittsburgh. No antenna.

Ar Q