splitter with amplifier... - Canadian TV, Computing and Home Theatre Forums
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post #1 of 39 (permalink) Old 2009-02-25, 12:51 PM Thread Starter
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splitter with amplifier...

Anyone


the cable coax entering the house is immediately split indoors with a 2 way nextech splitter (from RS), from one leg of the nextech splitter a piece of coax connects to an amplifier-splitter (1100 mhz) (from RS) which then feeds to 2 TV's with analog cable signal, from the other leg of the nextech splitter a coax goes to a TV with basic digital illico box (standard digital signal)


Is the amplifier-splitter necessary for the 2 analog cable TV's, or is that actually introducing more noise into the system, rather then creating improvement...


thanks
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post #2 of 39 (permalink) Old 2009-02-25, 01:22 PM
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Analogue signals degrade with a poor signal, so the amp could certainly be necessary. You could move the STB to the other TVs and measure the signal strength and S/N ratio with and without the amp to see the numbers and post here.

http://www.digitalhome.ca/forum/showthread.php?t=17719

Videotron will usually supply the appropriate splitters and amp if necessary, so that the RS stuff (which may not be good enough, especially the amp) could be replaced with the appropriate equipment. But check the signals first.

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post #3 of 39 (permalink) Old 2009-02-25, 08:59 PM Thread Starter
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57:

Great. Thanks. someone who knows their stuff....

Looks like I have some more interesting reading and learning to do.

By the way, when I asked the Best Buy folks if this was possible to measure, they were confused and said to forget about it with Illico standard digital STB...

thanks again
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post #4 of 39 (permalink) Old 2009-02-25, 10:23 PM Thread Starter
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update signal readings...

I have a SA Explorer 940 STB. I verified my HDTV connected to the STB, while one of the other 2 analog TV's was powered on. I left the set - up as it was - see post#1

Screen page 5 - "Current Quam" -

Most channels show:

Level: -16 dBmV (in orange writing)
S/N: 29 dB

Level ranges from -16 to -12 dBmV
S/N ranges from 27 to 30 dB

Ok, so from what I read up, this is not too good!

Should my next step be to test the HDTV directly connected to the incoming cable from the house entrance (no splitter, amp, extra cabling etc...basically remove the analog part of the set-up)

I had already complained to Videotron about the digital cable reception being worse than the analog cable reception, but they said they verified from their end, and all signal levels were within the standards...
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post #5 of 39 (permalink) Old 2009-02-25, 11:08 PM
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Amplifiers should not be necessary with cable. Sometimes signal levels degrade due to corroded connectors or damaged lines. That is usually noticeable either on the very low analog channels (2,3) as snow or the very high channels as weak signal levels and low S/N ratio. The cable company should fix the signal levels but there are a couple of caveats. 1. The signal level may be intentionally set to feed just one TV. 2. If the cable company comes out and connects more than one TV, you could get hit with installation fees and/or additional monthly charges.

If you want to keep the amplifier, it should go ahead of any splitters. With cheap one way amplifiers, the major exception is if a cable modem is connected. That also applies for digital boxes if two way connection is required (such as for PPV.) I would not use a RS amplifier either. Their equipment is generally poor quality and not suitable for modern cable systems. You need a good quality two way amplifier that can safely be placed ahead of any splitters and digital equipment.

I would contact the cable company to find out their policies regarding service calls and extra TV connections before making a decision. If you connect the cable box directly and still have a low signal, I would call the cable company for a service call to get that corrected first. If you decide to install an amplifier and/or do the signal splitting yourself, a better quality amplifier (expensive) and better splitters (inexpensive) are called for. You may also want to put good compression connectors on the lines. By the time you end up doing as good a job as the cable company tech would do, you may only end up breaking even on the installation cost. I would get the signal level corrected and try a new setup with new connectors and splitters but without an amplifier first.
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post #6 of 39 (permalink) Old 2009-02-25, 11:41 PM Thread Starter
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ScaryBob:
Makes sense, along the lines I was thinking - I forgot to mention I already changed over all the cables to RG6, with brass/gold fittings

Quote:
Originally Posted by ScaryBob View Post
...1. The signal level may be intentionally set to feed just one TV. 2.
I guess I will know this when I connect directly to the source cable...


Quote:
Originally Posted by ScaryBob View Post
...If you want to keep the amplifier, it should go ahead of any splitters. You need a good quality two way amplifier that can safely be placed ahead of any splitters and digital equipment.
RS told me to put the amplifier for amplifying only the 2 analog cable feeds, thus after the splitter. He was under the impression their amplifier was only compatible with analog. There was another, expensive one available, but the manager said he didn't know anything about it, and didn't trust it, as no one ever bought that one before...it's no wonder... great service eh...

something I don't understand, how does the amplifier detect analog vs digital feed, is it only by the frequencies...since my understanding is Videotron send the digital and analog signal down the cable, and the illico box decodes for the digital signal...will they eventually filter out somehow the analog signal...

When I changed to illico service under channel package B, I still have analog cable service on the original package A...

By the way if I am in a postion to complain, can they contest my use of the screen data...


thanks
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post #7 of 39 (permalink) Old 2009-02-26, 09:55 AM Thread Starter
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Update signal strength

OK, so I bypassed everything, and connected the DTV (approx. 50 ft RG6) coax cable (approx. 50 ft long RG6) directly to the cable entrence to the house, indoors, (at the ground block I believe). I also rebooted the illico box.

Page 5 info, current QAM side now indicates (on most channels):

Level: -13 dbmv (in orange writing)

S/N: 31 db

EQ gain: .9

Note: A few channels show -6 dbmv and 32 db mostly on channels below #20

If I take this up with Videotron (leaving aside the analog TV's for now), how can I show these values are in contradiction (or should I say "enough" contradiction) to their own documented standards for those numbers and therefore warrant correction. I know for a fact they will argue about the page 5 screen method used, they are in general very difficult to deal with...

I did not find SA Explorer 940 STB specs.

According to the specs for the other SA STB's models linked in this forum, my data would represent a marginal deviation, and only with respect to the "Level".
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post #8 of 39 (permalink) Old 2009-02-26, 10:43 AM Thread Starter
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original set-up equip

BTW:

I verified my initial set-up equipment:

All new RG-6 coax, with gold plate fittings;

Nexxtech 2-way splitter # 1502582X, 5-1100 MHz, each out leg indicates 3.5 db;

Nexxtech, TV-VCR-FM, 2 way amplifier splitter, # 150116, 2 W

DTV is LG 19LG30

CRT #1 is JVC (old)

CRT # 2 is Sanyo (ancient)
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post #9 of 39 (permalink) Old 2009-02-26, 01:48 PM
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I wouldn't go after a service call with receiver levels. If there are channels that don't work correctly, or if there is snow or interference on some analog channels (especially 2 and 3 or 14-21) then I would tell them that. If there are fees for extra TVs, you might want to leave the digital box directly connected. Weak signals and interference can sometimes indicate a corroded connection on an outside line. There should be no service fee for fixing that.

I would replace what you now have with a good quality 3 way splitter. Put the digital box on the 3db leg and the analog TVs on the 6db legs. You might get a little snow on the analog TVs but, as you say, they are not used much so it shouldn't be a big issue. If they exist, I would also replace any barrel connectors in the line or on wall plates.
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post #10 of 39 (permalink) Old 2009-02-26, 02:39 PM Thread Starter
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Still...

ScaryBob:

thanks for the useful tips and prompt replies.

Do you thinks based on my test results, that these signal levels are giving me the best possible digital picture quality

Also, still don't know what premise to use with Videotron to check the outside cables, I don't have snow, but the digital quality is not what I expected, somewhat blurred, and certainly not better than analog cable reception...

I will also try with a good 3 way splitter, since it seems like adding the amplifier isn't helping


thanks again
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post #11 of 39 (permalink) Old 2009-02-26, 03:13 PM
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Are you talking the digital channels on an HDTV or on an SDTV. If on HD, see the following on SDPQ:

http://www.digitalhome.ca/forum/showthread.php?t=18580

Be aware that with digital channels you either get them or you don't. With borderline reception you usually get massive pixellation. There is no decrease in picture quality on digital channels with decreased signal. That is only applicable to analogue signals.

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post #12 of 39 (permalink) Old 2009-02-26, 03:34 PM Thread Starter
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57:

yes I was talking about the HDTV, mine is an LG (720p), and I have it connected to basic digital service (basic illico, not HD illico) - no pixelation on any channels - so I guess you answered my question on the reception for my HDTV, thanks. It's just I read in the SA STB's links here that there is a specific "optimal" range for these figures, even for digital, but I did not think anything outside these levels would be that obvious in the reception. I continue to learn!

yes I will read up on the proper HDTV set-up also - thanks again

Also, am I wrong to assume it's impossible to use my illico box to test signal on the other 2 older crt analog TV's, since I suspect they have no ATSC tuner

thanks
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post #13 of 39 (permalink) Old 2009-02-26, 03:37 PM
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To answer the last question, you cannot test the TVs themselves, but you can test the signal on the cable that leads to those TVs, as mentioned in post 2.

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post #14 of 39 (permalink) Old 2009-02-26, 05:01 PM
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If you are watching standard, SD digital on a HDTV, picture quality is an issue. It can be even worse on cable due to the way some cable companies source the channel feeds. Satellite SD isn't much better (sometimes worse) so the best solution is to subscribe to HD.
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post #15 of 39 (permalink) Old 2009-02-26, 05:20 PM Thread Starter
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57:

Got ya! thanks
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