View Full Version : Drop amp recommendation
kevindd992002 08-05-09, 03:56 PM 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.
RCbridge 08-06-09, 12:11 PM 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!!
kevindd992002 08-06-09, 12:14 PM 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?
RCbridge 08-07-09, 08:10 AM 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.
kevindd992002 08-07-09, 11:01 AM Ok, but isn't it recommended to separate the TV connections from the cable modem connections?
RCbridge 08-07-09, 11:57 AM 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).
kevindd992002 08-07-09, 11:59 AM Ok. But in my case, you can just use one 8-port amp with active return path? Is it ok for the TV and cable modem connections to connect to the same 8-port amp?
RCbridge 08-07-09, 12:25 PM Yes if you need the additional gain for the modems.
Are the modems operational now?
If so look at the diag screen and check the downstream and upstream power levels.
olyteddy 08-08-09, 09:20 PM 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.
kevindd992002 08-11-09, 12:28 PM 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?
bfoster 08-11-09, 09:40 PM There is nothing wrong with your levels as they are.
Downstream is a little low, but the SNR is the important one.
kevindd992002 08-12-09, 01:47 AM 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?
RCbridge 08-12-09, 08:06 AM 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.
kevindd992002 08-12-09, 08:13 AM 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?
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 (http://www.cencom94.com/gpage4.html) 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.
RCbridge 08-12-09, 12:15 PM 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.
bfoster 08-12-09, 01:26 PM Or to make it simpler, why do you have and/or need 3 cable modems?
kevindd992002 08-12-09, 06:22 PM 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.
bfoster 08-12-09, 08:02 PM 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...
kevindd992002 08-13-09, 10:09 AM Of course it helps, I'm currently happy with my setup right now. It's helping me with multi-thread connections like Newsgroup and Torrent connections.
kevindd992002 09-01-09, 05:06 AM When you power up a drop amp, you will need a coax connection between the power adpater and the drop amp itself. My questions is, is there a limit on how long will that cable be? I'm planning to install the amp in a place where there is no power outlet and I'm thinking that I can just run a coax cable from inside the house to the place where the amp will be.
Please don't recommend reverse powering since I have enough cable to do the independent power adapter method and in my opinion that's the better powering between the two.
Thanks!
profundus-sanus 09-01-09, 07:47 AM how far are you talking about? if its anything over 25 ft i would just run an extension cord to it. im not a huge fan of running high voltage through coax for long runs.. if you can secure it properly up out of the way then it should be fine longer.. Just the power being surrounded by the ground scares me.
i would just get the 608-10r and run all of your equipment off of it. the only reason i can think of to split off your modems separate from cable is to give them higher signal to keep return path in spec. also we generally split modems off before the amplifier just because we don't stock an amplifier that boosts return path.
kevindd992002 09-01-09, 07:51 AM Oh ok. What do you mean the ground surrounding the power?
I already have the 608-10r, do I still need to ground the outer casing of that drop amp?
When you power up a drop amp, you will need a coax connection between the power adpater and the drop amp itself. My questions is, is there a limit on how long will that cable be? I'm planning to install the amp in a place where there is no power outlet and I'm thinking that I can just run a coax cable from inside the house to the place where the amp will be.
Please don't recommend reverse powering since I have enough cable to do the independent power adapter method and in my opinion that's the better powering between the two.
Thanks!
I've run power over coax 50+ ft. with no issues.
|