splitter with amplifier... - Page 2 - Canadian TV, Computing and Home Theatre Forums
Reply
 
LinkBack Thread Tools Search this Thread Display Modes

post #16 of 39 (permalink) Old 2009-02-26, 06:02 PM Thread Starter
Veteran
 
Join Date: Jan 2009
Location: Montreal
Posts: 2,421
testing...

ScaryBob:

Here's what I did, not sure I should have though...I connected the 2 way amplifier to acble entrence, then I connected from the amplifier to the 2 way splitter, and connected the HDTV (& illico) to one leg of the splitter (leaving the other leg open).


The signal data went out of whack, and the picture froze (pixelated somewhat)...


Then I removed the amplifier, connected the cable entrance to the 2 way splitter, connected the HDTV (& illico) to one leg of the splitter, and the analog TV to the other leg of the splitter.


The signal data is now as it was originally, as in post #4


The reason I'm doing this is get the best digital PQ, without paying Videotron more and more (like for HD). For the HD I am building my own OTA antennas...
balm is offline  
Sponsored Links
Advertisement
 
post #17 of 39 (permalink) Old 2009-02-26, 07:41 PM Thread Starter
Veteran
 
Join Date: Jan 2009
Location: Montreal
Posts: 2,421
best so far....interesting!

here's my 5th scenario,


I connected the 2 way splitter to cable entrance, then connected one leg of the splitter to the amplifier, then connected on leg of the amplifier to the HDTV (with illico box) and the other leg of the amplifier to one of the analog TV.

Then I connected the other leg of the splitter to the other analog TV.


So far the best signal values at the HDTV:


Level ranges: +4 to -9 dbmv (a few channels fluctuate between -9 and -10, 3 useless channels are at -15)

S/N ranges: 31 to 32 db (a few channels fluctuate between 30 and 31)

Eq. gain: .9


Based on this for optimum you need to have an amplifier, after the splitter, then your HDTV connected to one leg of the amplifier. In fact the splitter with the amplifier gives even better values than connecting the HDTV directly to the cable entrance!


This tells me two 2 things, the amplifier helped overcome the splitter loss and the amplifier improves Videotron's cable feed ! Also most of the loss is due to Videotron, not the splitter, since the only loss of the splitter is 3 db's...


Am i missing something here?
balm is offline  
post #18 of 39 (permalink) Old 2009-02-26, 08:21 PM
 
Join Date: Feb 2004
Posts: 119
Your signals are poor. A good S/N must be between 33 and 38 dbmV for 256QAM. If your S/N drop below 30, you will get picture and sound freezing, black screens, etc... Installing an amplifier won't fix the problem if your signal levels at the input of the amplifier are too low or noisy. Normally, cable companies install amplifiers when the signal is too low for feeding several cable jacks (normally 5 and up). The signal at the input of the amplifier must be strong enough and without noise, cause the amplifier will also amplify the noise like you are experiencing right now (low signal to noise ratio s/n). You need to call Videotron for a service call...

There's one more thing... Explorer 940 from Videotron has a firmware problem and don't give a good s/n signal reading. You will never see more then 33 dBmV of s/n with this set-up box. (even if the s/n is 34 or up). That doesn't affect the signal, it's just the reading, the meter that is bad. But with a signal so low with an amplifier connected (-9, -10, -15), you need a service call for sure.
superham is offline  
 
post #19 of 39 (permalink) Old 2009-02-26, 11:24 PM
57
Moderator
 
Join Date: May 2002
Location: Toronto, Rogers, 9865 & 8300-eHDD, Sharp LC75N8000U, Denon AVR4310Ci; Sony KDL40W3000, 9865
Posts: 56,069
There's also something wrong if the signal strength varies as much as your does (from +4 to -9). A couple of dB is fine, but this indicates a problem, either with the amp or splitter, or signal coming to the home.

57's Home Theatre (Latest equipment & photos)
57 is offline  
post #20 of 39 (permalink) Old 2009-02-27, 01:33 AM
Veteran
 
Join Date: Feb 2009
Location: The Dandelion City
Posts: 7,131
Quote:
connected the HDTV (& illico) to one leg of the splitter (leaving the other leg open).
That won't work correctly. I suggest you follow the advice in the previous two posts.
ScaryBob is offline  
post #21 of 39 (permalink) Old 2009-02-27, 07:30 AM Thread Starter
Veteran
 
Join Date: Jan 2009
Location: Montreal
Posts: 2,421
superham:

Thanks for the info.


I was comparing my numbers to this:

http://www.digitalhome.ca/forum/showthread.php?t=17719 - post #1


and here:

http://www.dslreports.com/faq/11900


So are you saying even if the S/N value was 35, assuming the E940 reading was working correctly, that my Levels (-9 to +4) are still bad...

So I guess in the end I need to know how to approach Videotron about this, they can be very intimidating. As I said before they claim their values from their end are within "normal", but I have doubts now and I want to ensure I am getting the best (PQ) possible digital signal for the money I shell out - remember I can't say I've had any drop outs, freezing, or pixelation...

Quote:
...A good S/N must be between 33 and 38 dbmV for 256QAM....

....But with a signal so low with an amplifier connected (-9, -10, -15)....
BTW, where do you get the should/must be reference values...

thanks again
balm is offline  
post #22 of 39 (permalink) Old 2009-02-27, 09:14 AM Thread Starter
Veteran
 
Join Date: Jan 2009
Location: Montreal
Posts: 2,421
Videotron signal strength, what next?

I connected my LG 19" LCD HDTV with basic digital illico box (SA Explorer 940)directly to the videotron house entrance cable after the ground block (removed all other equipment). 40 ft new RG6 coax, gold plate fittings, no joints.

these are the signal strength readings on most channels from the diagnostic HDTV screen:


Level: -12 (+/-2)

S/N: 31 (+/-)

Eq Gain: .9


Based on the other forums and threads, these values are not normal. I have been complaining about poor digital PQ, kind of blurry, some channels a little worse than others, but never any drop outs, or pixellisation. Videotron has told me all "values are within standards" from their end.


My questions are:

With respect to Videotron, am I allowed to use the diagnostic screen;

what are the documented normal reference values (should be) for Videotron and the SA Explorer 940 STB;

Can these values affect picture quality (such that one can notice it) when compared to optimum;

If not optimum, how do I prove to Videotron the above, and get them to make any improvements, as they can be very intimidating!



BTW, adding just one good quality 2 way splitter reduces Level values by 30%. The highest Level values I got were with a splitter, then 2-way amplifier. The Levels were -9 to +4 with fluctuations, and S/N of 31 to 32.

Another member told me the reading for S/N on this model illico box do not show the correct actual values due to a software flaw...


Also, what is the best 3 way splitter for cable in Montreal...


thanks
balm is offline  
post #23 of 39 (permalink) Old 2009-02-27, 10:57 PM Thread Starter
Veteran
 
Join Date: Jan 2009
Location: Montreal
Posts: 2,421
Amp specs

My RS 2 way amplifer says:

bandwidth: 50-900 MHz
Gain: 5.5 db min. (50-900 Mhz)
Noise figure: 5 dB max (50-500 Mhz)
6.5 dB max (501-900 Mhz)
Power requirements: 120 VAC\VCA, 2W


Is this a problem, is it normal to have a noise figure as high or higher than the min. gain????
balm is offline  
post #24 of 39 (permalink) Old 2009-02-27, 11:53 PM
57
Moderator
 
Join Date: May 2002
Location: Toronto, Rogers, 9865 & 8300-eHDD, Sharp LC75N8000U, Denon AVR4310Ci; Sony KDL40W3000, 9865
Posts: 56,069
That isn't the same as what you told us in post 1, or am I confused? That amp is not recommended since it should be rated 5-1000 MHz minumum and bidirectional.

57's Home Theatre (Latest equipment & photos)
57 is offline  
post #25 of 39 (permalink) Old 2009-02-28, 09:45 AM Thread Starter
Veteran
 
Join Date: Jan 2009
Location: Montreal
Posts: 2,421
57:

No you are not confused, I was...the amp rating is in fact 50-900MHz (1100 MHz in post #1 was for splitter).

The RS guy said the 2-way meant bi-directional...guess it actually means it's split 2 ways, correct...

BTW why 1000Mhz, if the TV channles frequencies max. is 770 MHz...

and why bi-directional, RS said that's only for Internet communication...

thanks for you patience!

Guess I should just try to return it!
balm is offline  
post #26 of 39 (permalink) Old 2009-02-28, 10:03 AM
57
Moderator
 
Join Date: May 2002
Location: Toronto, Rogers, 9865 & 8300-eHDD, Sharp LC75N8000U, Denon AVR4310Ci; Sony KDL40W3000, 9865
Posts: 56,069
Most splitters/amps that are rated at below 1000 MHz are not very good, hence the minimum 1000 MHz.

Bi-directional is required for any digital cable TV system so that the STB can communicate with the head end or node - for VOD, PPV, SDV (where applicable) allowing the head end to check your signal and other things, etc.

57's Home Theatre (Latest equipment & photos)
57 is offline  
post #27 of 39 (permalink) Old 2009-02-28, 12:09 PM Thread Starter
Veteran
 
Join Date: Jan 2009
Location: Montreal
Posts: 2,421
Quote:
Originally Posted by 57 View Post
...Bi-directional is required for any digital cable TV system so that the STB can communicate with the head end or node...
57:

1) Re. bi-directional, is this required also for an analog cable signal (no STB)...

2) If I'm getting signal readings (S/N, Level) on the TV, with amplifier in place, does that not mean then the STB is communicating with the "head end", or are those readings being "falsefied"

3)for the basic digital (STB) with no HD, or VOD or anything else, can the amplifier I bought, still help increase the "S/N" values, and/or optimize the "Level" values, make them worse, or is it useless????

also I assume the unit or specs have to say "bi-directional"...
balm is offline  
post #28 of 39 (permalink) Old 2009-02-28, 12:24 PM
 
Join Date: Feb 2004
Posts: 119
Signal levels don't affect digital tv picture quality, but if your
signal levels are out of spec, you can have picture and sound freezing,
black screens, etc.

When you call Videotron, they are able to see the live signal levels
of your set-up box and a log with the signal levels for a long period
of time. I suggest you to connect your terminal to the cable entrance
without any slitters or amplifier and syntonise the channels with
the worst signal levels. If you are not interrested by these channels,
just let the terminal turn-on on these channels when you are not home or
don't watch tv. By doing so, when you will call Videotron, they will
see the problem with your signal levels in the log.

They are able to see if you have audio/video discountinuity
(picture freezing), so if you don't have this issue and your signal is
not too bad (-12 is the lower edge), it's possible they don't do a
service call, cause after all, if there is no audio/video
discountinuity, there is no problem...

In fact, there is probably a signal problem. If a technician come
to your house to install Internet/phone service or a second cable jack,
he is suppose to have enough signal to split the cable with a 2-way
splitter (4 dBmV lost) whitout using an amplifier. In your case, that
means your set-up box will drop out of spec to -16 dBmV.

Don't wast your time and money by trying to fix it yourself,
the problem is probably with the cable line from the pole to the house
or with the equipment on the distribution line, installing an amplifier
won't fix that problem. Your amplifier is a "old fashion amplifier",
causing more bad than good, even for analog tv. It's very important
that your teminal is bidirectional, cause Videotron is using in
Pointe-Claire, a technology called Switching Digital Broadcast,
that need terminal to be 2-way to broadcast some speciality channels,
if not, you can have troubles to watch some channels sometimes.

Don't be intimidated by Videotron, you pay for the service and if
there is really a problem, they will fix it with pleasure. They want
to offer quality and trouble free telecommunication services. Be
advise that if you have some cable jacks that was not installed by
Videotron, they can't guaranty the quality, so you can have a charge
for the service call, it's why i suggested you to connect your
terminal to the cable entrance.
superham is offline  
post #29 of 39 (permalink) Old 2009-02-28, 12:39 PM Thread Starter
Veteran
 
Join Date: Jan 2009
Location: Montreal
Posts: 2,421
summary results

1) cable direct to TV, S/N= 31, Level= -12

2) cable to splitter to TV, S/N= 31, Level= -13

3)cable to amp to splitter to TV, S/N= 31 to 32, Level= -1 to -4

4)cable to amp to TV, S/N= 31 to 32, Level= 4 to 11

5)cable to splitter to amp to TV, S/N= 31 to 32, Level= 4 to -9
balm is offline  
post #30 of 39 (permalink) Old 2009-02-28, 01:28 PM
 
Join Date: Feb 2004
Posts: 119
Bidirectionality is not required for analog tv, but please don't connect this cheap amplifier to Videotron's network, it can cause problem to your service and to your neighbours.

You will always be able to see your signal levels, it's Videotron that won't be able to see your signal levels if the amplifier is not bidirectional, cause the amplifier block the upstream patch (your house to the head-end). If your set-up box is not bidirectional, you will get Status: Broadcast Only on the first diagnostic page. When the set-up box is communicated with the head-end, you will get Status : Ready.

A bidirectional amplifier let pass the upstream signal patch (5-42 MHz) and the foward patch (54-1000 MHz).

The signal must be strong enough and noise free at the input of any amplifier, even the better ones, if not, the problem will be worse, it's why you need the problem to be fix on a service call.

Signal levels are not the same depending of the channels, the frequencies you are syntonising. Some people use a splitter to watch a digital show and record an analog show at the same time, it's the way to do it, Videotron don't have any problem with that. If with the splitter your lower QAM signal is -13, it's kind of border line, but if you dont have any audio/video discountinuity issue, its up to the csr at the phone to decide to do a service call or not. That doesn't cost nothing to try it!!!
superham is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Canadian TV, Computing and Home Theatre Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome