Increasing Cable TV signal strength
 

On Thu, 09 Feb 2012 09:01:21 -0800, Jeff Liebermann
wrote:

How to Check Comcast Signal Levels
http://www.ehow.com/how_7777024_check-comcast-signal-levels.html
I'm not sure if this works on the newer set top boxes, but give it a
try.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Increasing Cable TV signal strength
 

On Thu, 9 Feb 2012 08:14:31 +0000, Ian Jackson
wrote:

In message , Jeff Liebermann
writes
Something is wrong. The nominal signal from the cable drop is suppose
to be 0dBm. If there's a splitter involved, they like to crank it up
to about 10dBm.

Careful! Don't get your dBm mixed up with your dBmV. There's around 48dB
difference! 0dBm is a massive 48dBmV. That would certainly make most
set-top boxes wake up and pay attention!

Oops. All my mentions of dBm should be dBmV. Thanks.

Range of acceptable signal levels. They're similar for DTV.
http://www.dslreports.com/faq/16085

How to check signal levels with a Motorola set top box:
http://www.ehow.com/how_12186368_check-signal-strength-comcast-digital-cable-motorola.html

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Increasing Cable TV signal strength
 

On Feb 8, 2:00*pm, amdx wrote:
Hi All,
I'm on a boat, about 170ft from the utility post.
Recently our cable company switched to the wonderful world of
Digital TV. I got the new digital converter and had no picture.
I took the box back and got a second box, still no picture. So now I
suspect a weak signal and confirm that it is the cable length. The cable
company came out and gave me a better cable than I had installed. At
this point I have a picture but it is intermittent. The signal at the
utility post has 3 outputs and had a four way splitter, I suggested the
cable guy put in two 2 way splitters and give me the stronger (first) tap..
* That got my signal to work almost all the time. I'd like to get the
signal to work 100% of the time.
* *I don't has access to electricity at the utility post, so an amp is
out. Although I could try an amp at the cable box end. Is that reasonable?
I would run two cables if there was a way to make it increase signal
strength.
* Getting anymore from the cable company is not an option.
* *Any ideas to get a better signal?
* * * * * * * * Mikek

PS.

* When the signal fails it seems channel 41 is ok and above 42 it breaks up.
Curious to know if there is an unusual frequency jump between those two
digital channels.

Google your cable box model. You should able to find ifo on how to
pull up a menu that shows signal strengh. -60dbm is about where my
sigal starts droping out

Jimmie

Increasing Cable TV signal strength
 

amdx wrote:

On 2/8/2012 7:50 PM, Joerg wrote:

Where does the other leg of that splitter go to? And is that end
properly terminated?

They go to two other outlets, that are used for transient boaters.
sometimes they are used and sometimes they sit unterminated.
I have not seen my problem better or worse when boats are in or out.
But I have several 75 ohm F connector terminations. It's worth a try.


Not really. If there are long unterminated 75 ohm cables after the
splitter, they are a crude termination. The splitter's backmatch
eliminates ghosting from reflections from the unterminated end.

--
You can't have a sense of humor, if you have no sense.

Increasing Cable TV signal strength
 

Michael Coslo wrote:

I don't know exactly how it's done now, but when I worked in the Cable
industry many moons ago, we had a lot of adjustment we could make. Even
more, we had variable by frequency attenuators so we could ensure that a
flat signal showed up.


Those are 'Equalizers' and used to cancel the cable losses. There is
some adjustment in the trunk amplifiers, but some brands just used a
plug in equalizer marked with the rolloff in dB while others had both.
The coarse plugin, and a variable equalizer to level the trunkline for
'Proof of Performance' tests.


--
You can't have a sense of humor, if you have no sense.

Increasing Cable TV signal strength
 

Joerg wrote:

amdx wrote:
Hi All,
I'm on a boat, about 170ft from the utility post.
Recently our cable company switched to the wonderful world of
Digital TV. I got the new digital converter and had no picture.
I took the box back and got a second box, still no picture. So now I
suspect a weak signal and confirm that it is the cable length. The cable
company came out and gave me a better cable than I had installed. At
this point I have a picture but it is intermittent. The signal at the
utility post has 3 outputs and had a four way splitter, I suggested the
cable guy put in two 2 way splitters and give me the stronger (first) tap.
That got my signal to work almost all the time. I'd like to get the
signal to work 100% of the time.

Looks like the cable guys screwed up.


In your opinion. If they are delivering the level called for in
their franchise, they didn't screw up. It has always been up to the
customer to pay for or provide extra equipment for non standard
installs.


--
You can't have a sense of humor, if you have no sense.

Increasing Cable TV signal strength
 

Robert Baer wrote:

amdx wrote:
Hi All,
I'm on a boat, about 170ft from the utility post.
Recently our cable company switched to the wonderful world of
Digital TV. I got the new digital converter and had no picture.
I took the box back and got a second box, still no picture. So now I
suspect a weak signal and confirm that it is the cable length. The cable
company came out and gave me a better cable than I had installed. At
this point I have a picture but it is intermittent. The signal at the
utility post has 3 outputs and had a four way splitter, I suggested the
cable guy put in two 2 way splitters and give me the stronger (first) tap.
That got my signal to work almost all the time. I'd like to get the
signal to work 100% of the time.
I don't has access to electricity at the utility post, so an amp is
out. Although I could try an amp at the cable box end. Is that reasonable?
I would run two cables if there was a way to make it increase signal
strength.
Getting anymore from the cable company is not an option.
Any ideas to get a better signal?
Mikek


PS.

When the signal fails it seems channel 41 is ok and above 42 it breaks up.
Curious to know if there is an unusual frequency jump between those two
digital channels.

Well, you could add an amplifier at the splitter where (nominally)
there is no power.
Use the coax center conductor for power; inline capacitors allow
signal to pass and feeding center via small choke allows DC but no signal.
Once upon a time there were little adapters that did this AC/DC thing...


A power inserter is used to put 9-28 volts DC on the coax, depending
on the amplifer you use.


--
You can't have a sense of humor, if you have no sense.

Increasing Cable TV signal strength
 

" wrote:

On Wed, 08 Feb 2012 18:52:10 -0800, The_Giant_Rat_of_Sumatra
wrote:

On Wed, 8 Feb 2012 18:21:19 -0800 (PST), Mark wrote:



Just a point. I may not have made it clear. I had the tech put in two
2way splitters and connect me to the first one. Hoping to gain 3db.
(or 4) and it did make a difference.

Where does the other leg of that splitter go to? And is that end
properly terminated?



Cable installers terminating things? You must be ****ing joking.
They would have to have an IQ above 25 for that.

*WAY* above your pay grade.


Makes you wonder what they paid him for at Time Warner, if he wasn't
smart enough to install a terminator.


--
You can't have a sense of humor, if you have no sense.

Increasing Cable TV signal strength
 

"JIMMIE" wrote in message
...
On Feb 8, 2:00 pm, amdx wrote:
Hi All,
I'm on a boat, about 170ft from the utility post.
Recently our cable company switched to the wonderful world of
Digital TV. I got the new digital converter and had no picture.
I took the box back and got a second box, still no picture. So now I
suspect a weak signal and confirm that it is the cable length. The cable
company came out and gave me a better cable than I had installed. At
this point I have a picture but it is intermittent. The signal at the
utility post has 3 outputs and had a four way splitter, I suggested the
cable guy put in two 2 way splitters and give me the stronger (first) tap.
That got my signal to work almost all the time. I'd like to get the
signal to work 100% of the time.
I don't has access to electricity at the utility post, so an amp is
out. Although I could try an amp at the cable box end. Is that reasonable?
I would run two cables if there was a way to make it increase signal
strength.
Getting anymore from the cable company is not an option.
Any ideas to get a better signal?
Mikek

PS.

When the signal fails it seems channel 41 is ok and above 42 it breaks up.
Curious to know if there is an unusual frequency jump between those two
digital channels.

Google your cable box model. You should able to find ifo on how to
pull up a menu that shows signal strengh. -60dbm is about where my
sigal starts droping out

Jimmie

================================================== ===

Yes, but be mindful of the difference between dBm and dBmV. The cable
industry often deals in levels on the dBmV scale.

There are places like this ...

http://www.maxim-ic.com/app-notes/index.mvp/id/808

where you can see some conversion equations. Jimmie's -60dBm equals -11.25
dBmV. Same power level -- different scale.

I have long known level requirements for the TV tuner's cousin, the cable
modem. The common DOCSIS 2 cable modems are usually spec'ed for -15dBmV to
+15dBmV and the smart operators try to keep inside +/- 12. Thus, you can
see that Jimmie's -11.25dBmV is near the low limit and that dropouts become
more likely in that neighborhood.

I little bit of google snooping revealed that DTV cable boxes would like
0dBmV and will usually be okay with -10dBmV to +10dBmV. Almost the same.

i hope this helps.

"Sal"

"Sal"

Increasing Cable TV signal strength
 

Michael A. Terrell wrote:
Joerg wrote:
amdx wrote:
Hi All,
I'm on a boat, about 170ft from the utility post.
Recently our cable company switched to the wonderful world of
Digital TV. I got the new digital converter and had no picture.
I took the box back and got a second box, still no picture. So now I
suspect a weak signal and confirm that it is the cable length. The cable
company came out and gave me a better cable than I had installed. At
this point I have a picture but it is intermittent. The signal at the
utility post has 3 outputs and had a four way splitter, I suggested the
cable guy put in two 2 way splitters and give me the stronger (first) tap.
That got my signal to work almost all the time. I'd like to get the
signal to work 100% of the time.
Looks like the cable guys screwed up.


In your opinion.


If their company cable box doesn't deliver a useful and reliable signal
I call that screwed up. One pays for a service and expects to either get
it delivered as promised or money back.


... If they are delivering the level called for in
their franchise, they didn't screw up. It has always been up to the
customer to pay for or provide extra equipment for non standard
installs.


Mike's install does not sound non-standard. 170ft cable drop towards
premises which is fairly normal, plus the cable company's set-top box.

--
Regards, Joerg

http://www.analogconsultants.com/