Cable amplifier: affect telephone via cable & suggested layout?

[Opus4]

Long ago, I got some good info about cabling in an older topic & it included some info about cable amplifiers. While I made use of the cable info, I'm only now getting around to really needing to add an amp.

Question 1: will having phone service on the cable system affect the type of amp that can be used? I don't think it would be any different that the existing need for a bidirectional-capable amp, but I would like to confirm that since I don't really know how phone service works on the cable system.

From re-reading old posts about amps, I keep seeing comments that the cable installers like to make one 2-way split to send one side to the modem & the other side to all the TVs. That isn't possible in my house, unless another cable is run all the way around the house just for the modem -- it is on the opposite side of the house where the cable comes in & where it is split for all the other connections, like this layout updated from an older post:

In - 
   2 way (-3.5 db drop each) Main TV room
     |----4 way -- TV + 3 tuners (-7.5 db drop each) (-11 db total)
     |
     | 20 feet or so
     |
    2 way (-3.5 db drop each)
      |-- TV (-7 db total)
      |
      | another 20 feet or so
      |
     3 way (db drop differs) Office
       |-- modem (-3.5 db drop) (-10.5 db total)
       |--TV (-7 db drop) (-14 db total)
       |--tuner (-7 db drop) (-14 db total)

Obviously, I still have an internet connection, despite those numbers.

The above system is working, but I now need to add additional connections in the main TV room & office. So...

Question 2: what type of amplification would be recommended -- this Electroline 8100 amp looks interesting in terms of boosting the return signal, but putting it at the start doesn't do much further down the line, so maybe a large boost just at the start is better, using something like this.

I've seen reverse amps, so maybe that's what I should consider near the modem if I end up with connections issues there. I don't know what type of loss there is on the return signal at each splitter -- same as the forward loss, maybe?

Thanks for any info provided.

- Andy

[gplasky]

So I have the EDA-FT08100. Now actually that is an amplifier and will amplify the incoming cable signal. The important thing is the zero return loss. The return is amplified but not boosted so the intent is to keep the return at the same level. Very important from a digital equipment perspective.

So the longest run I have is 57 feet to an analog tuner card in a seperate test PC. That signal is just as good as the dual tuners connected not further than 17 feet from the amp. I have the EDA-FT08100 connected right where the cable enters the house. I have 7 active runs in total.

I have a HDHR connected to it and it routinely shows between 88%-98% signal. Prior to that using 2 way and 3 way splitters the analog just looked dirty and the HDHR showed 80%-89 sometimes 90%. I'm very happy with the results.

Gerry

[paulbeers]

Originally Posted by Opus4

Long ago, I got some good info about cabling in an older topic & it included some info about cable amplifiers. While I made use of the cable info, I'm only now getting around to really needing to add an amp.

Question 1: will having phone service on the cable system affect the type of amp that can be used? I don't think it would be any different that the existing need for a bidirectional-capable amp, but I would like to confirm that since I don't really know how phone service works on the cable system.

From re-reading old posts about amps, I keep seeing comments that the cable installers like to make one 2-way split to send one side to the modem & the other side to all the TVs. That isn't possible in my house, unless another cable is run all the way around the house just for the modem -- it is on the opposite side of the house where the cable comes in & where it is split for all the other connections, like this layout updated from an older post:

In - 
   2 way (-3.5 db drop each) Main TV room
     |----4 way -- TV + 3 tuners (-7.5 db drop each) (-11 db total)
     |
     | 20 feet or so
     |
    2 way (-3.5 db drop each)
      |-- TV (-7 db total)
      |
      | another 20 feet or so
      |
     3 way (db drop differs) Office
       |-- modem (-3.5 db drop) (-10.5 db total)
       |--TV (-7 db drop) (-14 db total)
       |--tuner (-7 db drop) (-14 db total)

Obviously, I still have an internet connection, despite those numbers.

The above system is working, but I now need to add additional connections in the main TV room & office. So...

Question 2: what type of amplification would be recommended -- this Electroline 8100 amp looks interesting in terms of boosting the return signal, but putting it at the start doesn't do much further down the line, so maybe a large boost just at the start is better, using something like this.

I've seen reverse amps, so maybe that's what I should consider near the modem if I end up with connections issues there. I don't know what type of loss there is on the return signal at each splitter -- same as the forward loss, maybe?

Thanks for any info provided.

- Andy

Adding a cable phone line runs on the same principal as a Cable Modem.

First off, I am really surprised you have internet, with a 10.5db loss on your cable modem. At least you have the least db loss leg of your 3 way to your cable modem.....I can't have anything more than 7db loss without completely losing all signal, so you must have a damn strong signal coming into your house....

Second. Based on what I am seeing, you do not have a centalized Cable/Coax which really makes everything more difficult....You're best bet is to amplify the signal at entry point so before your first split. If you amply a poor signal, you aren't gaining anything. Your best bet is actually probably to get this:

http://www.cabletvamps.com/Products/ERA-4100.htm and install it before your 1st split. It will actually negate (to some degree) the DB loss that your cable modem is experiencing.

[Brent]

I can second Gerry's experience with the EDA-FT08100. I added that to my setup right at the point of the CATV into the house and it is an excellent device. I have the HDHR 2 feet away from the 8100, but then have cable runs from the basement to my office upstairs for all the other tuners. This isn't ideal, but the 8100 does a wonderful job with this situation for me.

[Opus4]

Thanks for the comments so far -- the HDHR is one item I'm going to finally be adding.

Originally Posted by paulbeers

Adding a cable phone line runs on the same principal as a Cable Modem.

Great -- so as long as my modem works, the phone service should too.

First off, I am really surprised you have internet, with a 10.5db loss on your cable modem. At least you have the least db loss leg of your 3 way to your cable modem.....I can't have anything more than 7db loss without completely losing all signal, so you must have a damn strong signal coming into your house....

I made sure to use the lowest db drop for the modem for just that reason -- I think it does get stopped if I use one of the other connections when I tested that.

Second. Based on what I am seeing, you do not have a centalized Cable/Coax which really makes everything more difficult....You're best bet is to amplify the signal at entry point so before your first split. If you amply a poor signal, you aren't gaining anything.

Yes, I plan to put the amp right at the start where the cable comes out the wall -- my UPS & so on is right there too.

Your best bet is actually probably to get this:

http://www.cabletvamps.com/Products/ERA-4100.htm and install it before your 1st split. It will actually negate (to some degree) the DB loss that your cable modem is experiencing.

That would be the reverse path amp that I mentioned seeing above -- I think that would go next to the modem to bump its return signal, since it has to return through a few splitters.


I just remembered something else: If I boost the signal coming in to cover everything all the way down the line (the 15db 1 port amp instead of the 8-way 8100 amp) and then end up too high mathematically at any of the TV/tuner connections, is it worth considering using an attenuator to drop the signal back down in a couple places?

I'm just leery of using the 8100 at the start because the coax has to split so much after that point due to my house layout.

- Andy

[bialio]

I think your best bet is to replace your first 2-way splitter with the electroline eda2200.

That gives you 11 db of boost on each of the primary legs.

In - 
   EDA2200 2 way (+11 db boost each) Main TV room
     |----4 way -- TV + 3 tuners (-7.5 db drop each) (+3.5db each total)
     |
     | 20 feet or so
     |
    2 way (-3.5 db drop each)
      |-- TV (+7.5 db total)
      |
      | another 20 feet or so
      |
     3 way (db drop differs) Office
       |-- modem (-3.5 db drop) (+7 db total)
       |--TV (-7 db drop) (+0.5 db total)
       |--tuner (-7 db drop) (+0.5 db total)

That would give you some wiggle room to add more splitters pretty much anywhere you want.

btl.

[gmijackso]

Just wanted to add my 2 cents.

One thing to be aware of when putting the amp at the beginning of the runs is that it is possible to feed too much signal to receivers. This is what generally causeses ghosting of your pictures. That said, I recently put a Motorola amp with 32x (15db) amplification and saw no problems only MUCH better pictures.

Just so it's out there for those who don't know, every 3db in loss means signal is dropped by half. So if your original signal is represented as 1, 3db loss means you're down to 1/2, 6db loss means your down to 1/4, 9 db loss means 1/8 etc.

I'm not a cable TV expert by any means, but I've always been willing to split a good cable feed 4 ways before feeling the need to amplify. Now not all cable feeds from the cable company are "good" so YMMV.

Just my 2 cents, maybe it helps.

[Opus4]

Originally Posted by bialio

I think your best bet is to replace your first 2-way splitter with the electroline eda2200.

Thanks; yes, that's another one to consider.

Originally Posted by gmijackso

One thing to be aware of when putting the amp at the beginning of the runs is that it is possible to feed too much signal to receivers. This is what generally causeses ghosting of your pictures.

That's why I was asking about adding attenuators -- I don't know how much signal is too much... too low is all I'm used to.

I'm still trying to find out the return loss at a splitter, in case anyone knows that.

I just found out how to get status info from my cable modem -- simply go to 192.168.100.1
Downstream:
SNR: 35 db
Power Level: -10 db

Upstream:
Power Level: 55 dBmV

- Andy

[hemicuda]

good 'ol Motorola

upstream:
41 dBmV power

down:
36 dB S/N
11 dBmV power

and that's on the modem tap of the 8100 w/ the DC power insertion splitter. keeps the amp powered from the UPS

[mikesm]

Originally Posted by Opus4

Thanks; yes, that's another one to consider.

That's why I was asking about adding attenuators -- I don't know how much signal is too much... too low is all I'm used to.

I'm still trying to find out the return loss at a splitter, in case anyone knows that.

I just found out how to get status info from my cable modem -- simply go to 192.168.100.1
Downstream:
SNR: 35 db
Power Level: -10 db

Upstream:
Power Level: 55 dBmV

- Andy

55 dbmv on the upstream? Ugh... That means the modem has to be yelling at the top of it's voice to be heard adequately at the CMTS. In my experience, this is going to be marginal, since some noise or other issue can push it over the edge pretty easily.

What as the upstream power level when you plugged the modem directly into the main feed from the cable company? if it's roughly the same, there is a plant problem.

Personally, I take the feed from the MSO and split it into two feed, one to the modem, and the other to a distribution amp that feeds the other stuff in the house.

[kevine]

What are good levels? Mine is split with a 2 way -3.5 dB splitter cable modem and into electroline 1x8 amplifier for tuners.

Mine is:
Upstream
Power Level: 39 dBmV

Downstream
SNR: 35 dB
Power Level: 0 dBmV

[Opus4]

Originally Posted by kevine

What are good levels?

Upstream
Power Level: 39 dBmV

Downstream
SNR: 35 dB
Power Level: 0 dBmV

I was trying to figure out good numbers last night & found a few web sites that showed the signal ranges... here's one.

I know my upstream 55 is right at the high end; any more & I would lose connection, which I alreay knew from when I tested it connected to the higher db drop port of my 3 way splitter long ago. There was a cable guy next door today & he commented that their modems can usually go up to about 59. He also said that whoever comes out to hook up the phone & digital cable boxes may just run a new line to that end of the house anyway & provide an amp, so now that I know what I should probably buy, I'll wait to see what equipment he leaves here. He seemed very concerned that I would buy a cheap amp from a local store - I said I knew better.


Edit: one more question about amps: do the same types of amps work for a digital TV OTA antenna? Is there even a need to use an amp if you split the antenna cable 3 or 4 ways?

- Andy

[Djc208]

Originally Posted by Opus4

I just found out how to get status info from my cable modem -- simply go to 192.168.100.1

Cool, thanks for the info.

When I re-wired the media wiring in the house I split the line from the street between the cable modem and the 8-way splitter the rest of the house uses. Looks like it worked.

I got: Upstream 47 dBmV

Downstream:
SNR: 37 dB
Power Level: 3 dBmV

[Menehune]

Originally Posted by Opus4

Edit: one more question about amps: do the same types of amps work for a digital TV OTA antenna? Is there even a need to use an amp if you split the antenna cable 3 or 4 ways?

- Andy

You may have a problem if your CATV amp does not have a wide enough bandwidth. OTA channels are carried in the UHF band which is much higher than the CATV channel frequencies. Channels 2-13 are the same frequencies in both systems, but above CH 13 the frequency assignments change.

Ch 14 OTA is 471MHz, CH 14 CATV is 121MHz.
CH 69 OTA is 801MHz, CH 69 CATV is 493MHz.
http://www.arrl.org/tis/info/catv-ch.html

I suspect a 1GHz CATV amp may work but since I have no OTA ATSC signals in my area, I have not tested my CATV amp with my antenna.

An amplifier just increases the level of any signals at the input. That is why if a cable system has bad shielding, CATV signals can interfere with aircraft communications and result in visits to the head office from the FAA and FCC.

Any splitter is a power loss. I would try the system with just the splits before purchasing an amp. With a large antenna properly oriented/pointed you may be able to receive a signal with enough level to have a viewable picture. If there was a long lead-in wire before the splitter or long wires after the splitter running all over the house, I would install an amplifier.

[SHS]

Andy how far is main line come in to house to the frist 2 way?

This best use in area with low singel loss EDA-FT08100 75" main line or longer run

This used with all ready high singel EDA-UG2802 which provides the exact same signal level at the output that is provided at the input

If the main is to high all you need is Signal Attenuator degrade the incoming singel

[Yooper]

My original feeder coming into the house was RG59 - even the underground line from the street feeder box. I had the cable company replace this with two RG11 feeders. I also replaced the RG59 in the house with quad shielded, solid copper core RG6 cable. I also added cat6 internet cable to all of my connector boxes in all of the room and installed all gigabit switches.

One of my feeds is dedicated to internet and the other is dedicated to video. My video server is located in my basement next to my wiring box. I have measured all the cable lengths and done the calculations and added a 4 way amplifier that compensates for the video loss all the way from the street connection.

I have two Hauppauge dual tuners in my video server - which only needs two video feeds. These come directly from a 4 way amplifier. The other two lines go to RG6 lines that feed to two TV sets that use a direct video signal.

The real advantage to the SageTv system is that once the signal goes into the video server, the signal is distributed in a loss less fashion via nternet cable to all the SageTv media extenders. I now how two HD100s and an MVP. I have been replacing the RG6 cable feeds with loss less internet feeds.

I hope in the future to have all the TVs work off of the SageTV server.

I have learned a few things from this:

1. Amplify the signal as early as possible - the noise is also amplified so you want to amplify the signal with the highest signal to noise ratio.
2. Use the best compression fittings on your cable - not the cheap Radio Shack aluminum crimp fittings.
3. Use the best cable you can find. I suggest quad shield RG6 with a solid copper core.
4. Use the best splitters you can find. I use Monster splitters which have the lowest loss of any - but they cost a lot more.
5. Measure the line lengths and do the calcs to compensate for your actual losses.
6. Locate you video server as close as possible to your video feed and compensate exactly for the line losses.
7. Replace your video feeds over RG cable with loss less internet feeds via an extender box connected to the video server.
8. Place your cable modem as close as possible to your feed source. In my case I do not have any amplifiers in this line. If you only have one line, use a splitter with one line going to the cable modem and the other line used for video.

I spent probably 6 months working on this some time ago. I keep adjusting and changing the cabling as I get more media extenders.

I find this to be a lot of fun.....

[kevine]

Originally Posted by Opus4

I was trying to figure out good numbers last night & found a few web sites that showed the signal ranges... here's one.

Thanks, Andy. Good info. Guess I should feel lucky.

[SHS]

Edit: one more question about amps: do the same types of amps work for a digital TV OTA antenna? Is there even a need to use an amp if you split the antenna cable 3 or 4 ways?

Sometime it is a yes any time you start split the antenna cable
Take time read this it help
http://www.hdtvprimer.com/ANTENNAS/basics.html

[Opus4]

SHS & Menehune: thanks for the frequency info. I guess that means the same amps should cover OTA channels, since the specs I saw on the Electroline site do say it goes up to 1000 Mhz. I kind of figured they ought to work, but I didn't want to simply make the assumption. And, yes, I'll try it w/o the amp first.

Originally Posted by SHS

Andy how far is main line come in to house to the frist 2 way?

Let's see... the full story is something like this: ~30 feet from the box in our front yard to the side of our house + ~30 feet or more to the outlet in the center of the house -- that's where it gets split the first time in the diagram in the first post. But after talking to the guy working in my yard the other day, I'll wait to see if the installer decides to change any cable runs. As I mentioned above, he thinks the installer may run a new cable to the other end of the house & give me an amp too, just to prevent me from buying something cheap. I'll see what happens, but thanks to the above info I now know what to buy if I need to.

- Andy

[stevenkd]

I have too many cable runs in the house and have had issues for quite some time with signal quality. I had bought a fairly expensive amp from Radio Shack a few years ago that was designed to be put in line and had an adjustment knob on it. While it helped some, it never really did a good job. Last fall I switched to digital cable and the amp did not work at all for the digital cable box. I have Comcast digital cable, phone and internet. My configuration prior to putting int he new drop amps was:
4 way splitter at the incoming cable:
Modem
DCP501 box in Living room
Cable run to computer room for Sage TV setup
amplifier

3 way splitter from amp
Cellar TV
Kitchen TV
Bedroom TV

4 way splitter at PC
DCP501 (hooked to s-video on PVR-500)
DCT2224 (hooked to s-video on HVR-1600)
PVR-500 for second tuner to be used as an analog tuner
QAM on HVR-1600

I was getting extremely poor reception on the PVR-500 (it is the A version). Several channels on the digital box did not come in, just said channel will be available shortly.

On the DCP501 in the living room things worked ok, but on some of the channels the television would skip once in a while.

Bought an EDA-FT08100 and a EDA-UG28002. I put a 2 way splitter at the line coming into the house, one side to the cable modem the other to the EDA-FT08100. I then hooked all of the other 5 inputs to the EDA-FT08100. Next I put the EDA-UG28002 in the computer room and hooked the 4 inputs to that.

What a world of difference. Even the analog side of the PVR-500 is clear. Where I had decent reception at the analog tv's, I now get great reception. I now get all the channels on the digital cable boxes, no skipping.

It was expensive, but with all the other money I have invested in this system it is well worth it to finish the job and get some great quality recordings and reception.