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Discussion Starter · #1 ·
I have four cable TVs and three cable modems, what amplifier would you recommend I use, which of these choices is best:


1.) 1 Electroline EDA-FT08300 8-port Drop Amplifier that would take care of the seven connections and the remaining port (1) terminated by a 75-ohm terminator.


2.) 1 Viewsonics VSMA-608C-10R 8-port Drop Amplifier that would take care of the seven connections and the remaining port (1) terminated by a 75-ohm terminator.


3.) 1 Viewsonics VSMA-604C 4-port Drop Amplifier that would take care of the four cable TV connections and 1 Viewsonics VSMA-604C-10R 4-port Drop Amplifier that would take care of the three cable modem connections and the remaining port (1) terminated with a 75-ohm terminator.


or


4.) 1 Viewsonics VSMA-604C 4-port Drop Amplifier that would take care of the four cable TV connections and 1 Viewsonics VSMA-608C-10R 8-port Drop Amplifier that would take care of the three cable modem connections and the remaining ports (5) terminated with 75-ohm terminators.



I'm confused which drop amp to use since some guide says that too much amplification on the "return path" would cause problems. The Viewsonics VSMA-604C-10R provides a +3 dB return path gain which might "overload" the return path signal. This makes me worried about config #3.


Then again, I read in some guide that it would be better to not have both TV connections and cable modem connections in one amplifier which makes me worry about configs #1 and #2 and makes me lean toward config #4 as the best configuration for my application.




Can you provide me these specs for the EDA-FT08300:


Noise Figure

Maximum Return Path Input

Maximum Return Path Output

Return Path Second Order Distortion

Return Path Third Order Distortion



What is its difference in comparison with the old EDA-FT08100?


Thanks.
 

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Quote:
I'm confused which drop amp to use since some guide says that too much amplification on the "return path" would cause problems. The Viewsonics VSMA-604C-10R provides a +3 dB return path gain which might "overload" the return path signal. This makes me worried about config #3.

Where did you see this?


if at present your cable modems are working go into the diag screen and check the upstream power level if you are reading above 50dbmv (that is still an acceptable level)

but that means you have a lot of attenuation to overcome to reach the CMTS.

A slight gain in the signal means that the modems will work a little less to achieve the desired level that the CMTS wants to see.

Usually a little boost is a good thing unless the noise figure is really bad!!
 

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Discussion Starter · #3 ·

Quote:
Originally Posted by RCbridge /forum/post/16954083


Where did you see this?


if at present your cable modems are working go into the diag screen and check the upstream power level if you are reading above 50dbmv (that is still an acceptable level)

but that means you have a lot of attenuation to overcome to reach the CMTS.

A slight gain in the signal means that the modems will work a little less to achieve the desired level that the CMTS wants to see.

Usually a little boost is a good thing unless the noise figure is really bad!!

Ok. I saw it in the site of cabletvamps. Well, if my upstream level is below 50dBmV already, I don't need a return path gain right?


What's better anyway, to use 1 8-port amp for all my seven connections or 2 4-port amps that will separate the TV connections from the cable modem connections?
 

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Well, if my upstream level is below 50dBmV already, I don't need a return path gain right?

If you add an amp the cable modem upstream level will drop by about the amount of gain

that is a good thing the lower the upstream power from the cable modem the better.


Are you going to locate the splitters in the same location?

If so I would just use the one 8 way, if you go for two 4 way you also need a 2 way so to keep the number of connections to a minimum I would use the 8 way.


All of the signals will be together prior to the first split and the return signals after they are combined going back to the cable plant.
 

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Some people will split the cable modem before adding an amplifier this is usually done if the amplifier has a loss for the return signals. Again that makes your cable modem work harder and if pushed to the limits your upstream can be intermittent (if it locks at all).
 

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What makes you think you even need a drop amp? is there a problem you're addressing with it? I have 5 TVs, 3 VCRs, 1 DVD recorder, a Tuner card for my laptop and a cable modem all connected and fully functional without an amp.
 

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Discussion Starter · #10 ·
Yes I'm sure I need an amp. These are the diagnostic signal levels of my three modem:


Downstream: -15 dBmV, Upstream: 55 dBmV, and SNR: 33 dB.


So, if you were me, won't you need an amp? Lol..


BTW, what is the reason why most people prefer to separate the amps for the TVs and Cable Modems?
 

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Discussion Starter · #12 ·

Quote:
Originally Posted by bfoster /forum/post/16984674


There is nothing wrong with your levels as they are.


Downstream is a little low, but the SNR is the important one.

Upstream is even high, upstream levels should be less than 50 dBmV.


My question is simply about connecting TV and Cable Modem to one amplifier, is it advisable?
 

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Quote:
Downstream: -15 dBmV, Upstream: 55 dBmV, and SNR: 33 dB.

These numbers say that either you have a low signal coming into your home or you have a lot of attenuation within your home.

The cable modem is maxed out on power (upstream level).



Can you describe the layout of devices and splitters at present.
 

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Discussion Starter · #14 ·

Quote:
Originally Posted by RCbridge /forum/post/16986302


These numbers say that either you have a low signal coming into your home or you have a lot of attenuation within your home.

The cable modem is maxed out on power (upstream level).



Can you describe the layout of devices and splitters at present.

Yeah, very low signal and high upstream level.


My current setup is like this:


Spliiter in post -> 3-way splitter -> 3 cable modems

-> 4-way splitter -> 4 TV connections


The signal coming from the ISP/TV provider is really low and they don't want to fix it, so let's rule out that. I'm from the Philippines.


So the only thing needed is an active amplifier with an active return path.


My question is that if it is OK to combine the 4 TV connections and 3 cable modem connections into one 8-port Viewsonics with Active Return Path amplifier?


Or is it recommended to separate the TV connections and cable modem connections by using two 4-port active amplifiers?
 

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Quote:
Originally Posted by kevindd992002 /forum/post/16986316


Yeah, very low signal and high upstream level.


My current setup is like this:


Spliiter in post -> 3-way splitter -> 3 cable modems

-> 4-way splitter -> 4 TV connections


The signal coming from the ISP/TV provider is really low and they don't want to fix it, so let's rule out that. I'm from the Philippines.


So the only thing needed is an active amplifier with an active return path.


My question is that if it is OK to combine the 4 TV connections and 3 cable modem connections into one 8-port Viewsonics with Active Return Path amplifier?


Or is it recommended to separate the TV connections and cable modem connections by using two 4-port active amplifiers?

Get one of these HCDA-1FRA-AG amps. It is a single port drop amp with 15dB gain on the forward and 10dB gain on the return. Keep the cable modems and TVs on separate splitters as you currently do.
 

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Reading all of your set up description and working backwards from the cable modem.

If the modem is reading -15dbmv and you have a 3 way (probably a 4 way with a port loaded) you lose 7db and with a 2 way prior to that you lose another 3.5db.

Let's assume you have another 2db cable and connector loss (don't know how long your cable runs are).

Based on the facts and assumptions I would say your signal coming into your home is about 0dbmv (that is still low for entry into your home).


If you use an 8 port distribution amp for everything you will eliminate the loss of the splitters you don't need much gain.

It is okay to use the one amp for everything as long as the return path has no loss or a slight gain, remember all signals are together prior to your first split.
 

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Quote:
Originally Posted by kevindd992002 /forum/post/16989905


Let's put it this way. Internet here in the Philippines is very slow and you need to use multiple modems load balanced to get decent download speeds, hence why I use three modems.

No way that can help you, UNLESS they are throttling each individual modem...
 
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