Cable amplifier: affect telephone via cable & suggested layout?

[Yooper]

When you add a 4 way splitter, each output has one fourth of the original signal strength. Likewise, for a 2-way you get half the input signal on output. A common misconception is that you get the same output as input.

The idea is to configure your system with the least number of splitters.

I also do not like doubling up on amplifiers - my experience is that increases the noise level too high.

So, you should use the least number of splits and the least number of amplifiers. I highly recommend measuring the cable lengths, computing the losses due to these lengths, adding in the losses due to the splitters, and then configure your amplifier to match these losses.

It is possible also to over amplify your signal.

[Opus4]

Originally Posted by Yooper

It is possible also to over amplify your signal.

That's probably why the 2nd item was the EDA-UG2802 (the above post said '28002', but maybe that was a typo?). It says it is for use after the signal was already amplified, so it doesn't get boosted more.

- Andy

[SHS]

Originally Posted by Yooper

When you add a 4 way splitter, each output has one fourth of the original signal strength. Likewise, for a 2-way you get half the input signal on output. A common misconception is that you get the same output as input.

The idea is to configure your system with the least number of splitters.

I also do not like doubling up on amplifiers - my experience is that increases the noise level too high.

So, you should use the least number of splits and the least number of amplifiers. I highly recommend measuring the cable lengths, computing the losses due to these lengths, adding in the losses due to the splitters, and then configure your amplifier to match these losses.

It is possible also to over amplify your signal.

As andy point out it more likely it a EDA-UG2802 which is a distributer splitter amplifier which provides the exact same signal level at the output that is provided at the incoming input unlike a reg splitter where you get a automatic db loss which can be any where from 3.5db all way to 15db insertion loss depend on the number port output.

[Menehune]

Originally Posted by Yooper

When you add a 4 way splitter, each output has one fourth of the original signal strength. Likewise, for a 2-way you get half the input signal on output. A common misconception is that you get the same output as input.

The idea is to configure your system with the least number of splitters.

I also do not like doubling up on amplifiers - my experience is that increases the noise level too high.

So, you should use the least number of splits and the least number of amplifiers. I highly recommend measuring the cable lengths, computing the losses due to these lengths, adding in the losses due to the splitters, and then configure your amplifier to match these losses.

It is possible also to over amplify your signal.

If possible, I prefer taps since you can send the exact signal level you want to the drop without reducing the downstream signal levels too much. Blonder Tongue has a Broadband Reference Guide (registration required) that has many helpful hints, cable loss calculations, etc.

At work I have actually had to attenuate the inputs to some of my 50db amps due to overmod Then you have the one CCTV channel that is 20db above the others at the combiner that needs to be attenuated as well...

[stevenkd]

Yes it was the EDA-UG2802, and I bought it specifically because it was for use as the 2nd amp. Edited the 1st post and still left that error in. May not be for everyone, but my reception at all points is great now. The reception of the tuner side of the pvr-500 was pretty much unusable before. And as I said there were some digital channels that did not work at all. Everything comes in crystal clear now.

[Opus4]

Originally Posted by Menehune

If possible, I prefer taps since you can send the exact signal level you want to the drop without reducing the downstream signal levels too much.

Would you explain taps a little more, if I don't have this right? It sounds like a tap sends the signal through the main line w/o much (how much?) loss, while the tap connection takes whatever loss it is rated at. That seems strange, so please correct me if that is way off.

If that is what it does, I could see using that to split side lines for TVs while keeping the main line's power for the cable modem & other devices further down the main line.

- Andy

[MattHelm]

Originally Posted by Opus4

... will having phone service on the cable system ...

That's just hooked to the cable modem, so if it works .... (I think, as it's Voice Over IP)

Originally Posted by Opus4

... recommended -- this Electroline 8100 amp looks interesting ...
- Andy

I put a Electroline 8000 amp (same as 8100, but no return path, but dad has DSL) in, and I have a few things to point out.
1. It can be mounted outside, so you could run that second line around the house. (power is supplied thru one of the COAX lines that go near an AC outlet)
2. On the downstream side, each output is +3db, so each can be split once, and only be -0.5db, so you can really drive 16 tuners with this amp. (unless you are running very long cables) I just put in 1 line for every 2 tuners I planned in a location.
3. If there is ANY way to get a single line to the modem, then split -3.5db max., that would be best.
I ran a bunch of coax thru the floors (where dad wanted them) and all his TVs show a huge improvement.

[Menehune]

Originally Posted by Opus4

Would you explain taps a little more, if I don't have this right? It sounds like a tap sends the signal through the main line w/o much (how much?) loss, while the tap connection takes whatever loss it is rated at. That seems strange, so please correct me if that is way off.

If that is what it does, I could see using that to split side lines for TVs while keeping the main line's power for the cable modem & other devices further down the main line.

- Andy

Correct. Taps have low insertion losses-a quick web search found 3db and 1db insertion loss. Taps can have up to 40db loss on the tap port.
http://www.hometech.com/video/splitters.html#CV-TP
http://www.oatco.com/catv_tap.html

By using taps, you can avoid the cabling expense of home running all TV cables to your main telcom room by daisy chaining the cable. Good for retrofits where large cableways are not available, old installs that have tiny conduits installed in a daisy chain or very large buildings and very long runs.

Calculate the system cable loss, add the insertion loss of all taps, calculate the minimum signal at the furthest TV. Then get an amp that will overcome the losses. Calculate each tap's attenuation to deliver a consistent level to the TVs.

[Opus4]

Thanks for the extra info.

- Andy

[Opus4]

An update: The cable installer threw up in my front yard and then hooked everything up... just hope it wasn't contagious. I strongly suggested rescheduling, but didn't refuse the installation and kept my distance. He agreed there wasn't a good way to run a new wire for the modem, but said Cablevision doesn't let him install amps anymore.

The new modem (Scientific Atlanta DPC2203C) works fine & telephone service seems OK so far. (There was an echo one time when I called my parents, but they thought it might be because they are in Iowa... are there a lot of echos in Iowa??) The downside to the modem is that it has the status page disabled, so I have to call support to check signal strength & they said they can't enable the modem's status pages.

I decided to get the amps from cableTVamps.com. I probably could have gotten them a little cheaper via their ebay auctions, but I'm impatient & didn't want to wait to win auctions. They offer to review layouts & make suggestions; here is what they suggested:

In - 
   EDA-FT08100 8-way amp in Main TV room
     |---- 7 outlets for TV & tuners
     |
     | 20 feet or so
     |
    Tap with -6db side line to TV
      |
      | another 20 feet or so
      |
     2-way splitter in Office
       |-- modem
       |-- EDA-FT08000 8-way amp for tv & tuners

Actually, I'm unclear whether they meant to use a 2-way splitter in the office to feed the modem + 2nd amp, but that seems to make more sense to me because that amp has a large drop on the return path.

I asked a few times to double check about the 8000 in the office rather than another 8100 or a 2802 & they reiterated to use the 8000 instead of either of the other 8-way amps for some reason. I'll defer to their experience with the amps & see what happens. I'll check the signal levels with the cable co when it is all done.

Oh -- and I moved the cable from the roof-top antenna to the main TV room & now also have great OTA digital reception on quite a number of channels from the NYC area.

- Andy