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chong67

join:2001-11-18
Jonesboro, GA

1 edit

Do I need to get an amplifer and active return?

I notice my HDTV channel get blockly and static and making all these static noises when I plug in my 4 way splitter. One outlet goes to the TV, one to the computer and one to the cable modem.

All these goes away when I just only have the main cable toward the TV.

I notice it happen more at night then in the day time.

My modem stat is:

Downstream:
S/N Ratio: 37 db (4 channel)
Power Level: -1 dBmv

Upstream:
Power Level: 50 dBmv

Question:

1. Do I need to get a 4 way amplifier?
2. Do I need to get one with active return?
3. Do I need all these setup at all?



telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15

Re: [Connectivity] Do I need to get an amplifer and active retur

The modem status info you provided, while it looks good (-1 dBmV downstream power level, 37 dB SNR), it only applies to the relatively small band of frequences allocated (usually in the 500 to 700 MHz range) to handle the cable modem downstreams. The TV channel(s) that has the problem could be hundreds of MHz away from there.

It would be more useful for you to get the signal status info on the particular QAM carrier(s) that carry that TV channel(s).

See this post of mine in another thread about that: »Re: [HD] Fox Ohio Valley College Football Broadcast

Going by the modem status you posted, you will likely not need to use an amp, but instead, to just fix a cabling/connecter(s)/splitter(s) issue.

If the problem is not inside your home, you would then need a tech visit to investigate an outside issue.



chong67

join:2001-11-18
Jonesboro, GA

Telcodad, I dont have a cable box. I look at my HDTV and the signal strength thing is grey out. I dont know any where to check the signal.

I got my 4 way splitter (no idea what ohm or freq it is. Archer brand. Radio Shack?) and the splitter and cable are from 15+ years ago when there are no HD stuff.

The longest cable from the 4 way slitter is about 8 feet. Other is 4 feet.



telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15

said by chong67:

Telcodad, I dont have a cable box. I look at my HDTV and the signal strength thing is grey out. I dont know any where to check the signal.

Sounds like you are directly connecting the cable to your HDTV then, using its "Clear QAM" cable tuner.

said by chong67:

I got my 4 way splitter (no idea what ohm or freq it is. Archer brand. Radio Shack?) and the splitter and cable are from 15+ years ago when there are no HD stuff.

You need to try changing to a higher quality splitter. See this thread: »[Connectivity] Recommended splitter Those 2-way splitters all have 4-way versions that you can try.

said by chong67:

The longest cable from the 4 way slitter is about 8 feet. Other is 4 feet.

While your cables are relatively short, they could be damaged in some way that could be causing frequency/attenuation variations. Otherwise, there may be a connector issue on one of those cables. See this thread for cabling info: »Comcast cabling question


chong67

join:2001-11-18
Jonesboro, GA

Telcodad,

Yes I use "Clear QAM".

Since I need 4 outlet, do you recommend a 4 way splitter or should I get a amplified splitter?

I read there is a 3 way splitter, one is at 3.5 ohm and the other 2 outlet at 6 ohm or something.

I will be getting a few RG6 from monoprice today.

I got too many variables at play. Dont know which is cheaper to try first.

My Upstream Power level is not that great at 50 dBmv. It should go lower. I wonder if a active return amplifer will help.



ClockerXP

join:2001-05-24
Sterling Heights, MI
kudos:1
Reviews:
·WOW Internet and..
·Comcast
reply to chong67

Plug the cable modem directly into the line coming into the house and report your signal levels there. It will be easier to make a recommendation that way.

It looks like you only need three connections (TV, Cable Modem, Computer Tuner). If that's correct, the best way to do it without an amp may be to use two 2-way splitters. First split goes to the cable modem and the 2nd 2-waysplitter. Then the 2nd spliiter feeds the TV and the Computer tuner).



telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15

Yes, so you can stop a Comcast tech if you see one in your neighborhood, or stop by an office, and see if they can give you two 2-way splitters. If not you can order them from Amazon: »Re: [Connectivity] Recommended splitter

As ClockerXP See Profile suggested, then hook them up like this:

                          ---> Cable Modem
                        / 
---> 1st 2-way splitter 
                        \
                          ---> 2nd 2-way splitter < TV and PC Tuner
 

Cablejim1087

join:2012-09-21
Bath, ME
reply to chong67

You may want to have your outside lines checked if your tv is macro blocking also because your modem power level of 50 is at the end of the required specs. As the others stated as well a3way or 2 2 ways will get proper signal to modem.



telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15

said by Cablejim1087:

You may want to have your outside lines checked if your tv is macro blocking also because your modem power level of 50 is at the end of the required specs. As the others stated as well a3way or 2 2 ways will get proper signal to modem.

Hopefully, if chong67 See Profile replaces his questionable-quality 4-way splitter with two high-quality 2-way ones, and in the suggested configuration, he should lose several dB of attenuation in the upstream path, and thereby reducing his modem's upstream power level to somewhere in the mid-40s dBmV.


chong67

join:2001-11-18
Jonesboro, GA

Hello everyone.

I finally had a chance to plug the cable from outside my house straight directly into the modem without doing any splitter.

Here are numbers:

Downstream:
SN Ratio: 37db (stay the same)
Power level: 5 dBmV (from -1)

Upstream:
Power level: 44 dBmV (from 50dBmV)



chong67

join:2001-11-18
Jonesboro, GA

After doing a cold boot my modem, I got 3 channel Upstream now. Bonding right? I didnt know this.

I been getting 4 channel downstream bonding.



chong67

join:2001-11-18
Jonesboro, GA

I use my dish 2 way splitter rated at 950-2150 Mhz and I cannot see any of the TV channels on my computer and my HDTV.

What is a good 2 way freq splitter to get for Comcast?

I notice 2 way splitter to my modem, the stat stay the same as doing it directly to the modem.

Shall I go ahead and do the TWO way splitter like you all recommend? Get it from Amazon?

I will get RG6 cable too. I wish they sell it at 6 inch long.

I dont need the amplifier with the active return thing right? Not necessary?

Thanks for all your advice.



chong67

join:2001-11-18
Jonesboro, GA
reply to chong67

Re: Do I need to get an amplifer and active return?

I have TWO 6 inch cable and they are from Dish network. They are RB6 right?



THZNDUP
Deorum Offensa Diis Curae
Premium
join:2003-09-18
Lard
kudos:2
reply to chong67

Re: [Connectivity] Do I need to get an amplifer and active retur

If you use the two 2-way splitters you are introducing an extra component that may/may not have an impact-the jumper to interconnect them.

You could just use the 3-way splitter and eliminate the jumper all together as you mentioned. An unbalanced 3-way will have one port w/3.5db loss and two with 7db loss. Same as using the two 2-ways.

Hook the modem to the 3.5db port and the TV/PC tuner to the 7db ports.
--
one should not increase, beyond what is necessary, the number of entities required to explain anything



telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15
reply to chong67

said by chong67:

I use my dish 2 way splitter rated at 950-2150 Mhz and I cannot see any of the TV channels on my computer and my HDTV.

That is because the Comcast cable signals are all below 950 MHz. That splitter is designed for the L-band signals that are output from satellite dish LNBs.

said by chong67:

What is a good 2 way freq splitter to get for Comcast?
:
Shall I go ahead and do the TWO way splitter like you all recommend? Get it from Amazon?

As THZNDUP See Profile has suggested, you can probably just use one unbalanced 3-way splitter like the Antronix CMC2003H: »www.amazon.com/ANTRONIX-CMC2003H···01E4T3YK

said by chong67:

I will get RG6 cable too. I wish they sell it at 6 inch long.

Actually, RadioShack sells an RG-6 cable in a 1 foot length: »www.radioshack.com/product/index···11051589

said by chong67:

I dont need the amplifier with the active return thing right? Not necessary?

From the modem signal levels and SNR that you reported without any splitters, you should be fine without using an amp.

said by chong67:

Thanks for all your advice.



chong67

join:2001-11-18
Jonesboro, GA
reply to chong67

Re: Do I need to get an amplifer and active return?

Thank you all for the quick reply.


nrobot80

join:2012-12-05
Union City, GA

The cheapest and most effective way to get good signal and a good TV picture is to have a tech come out and replace your inside wiring. The Radio Shack and Amazon splitters and cable you buy may work but they may block your return path, which is essential for Internet access, and they may not be shielded to the point Comcast requires. Comcast wiring equipment is rated to block out noise and minimum signal loss. They may charge you a fee but it will be done correctly.



telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15

said by nrobot80:

The cheapest and most effective way to get good signal and a good TV picture is to have a tech come out and replace your inside wiring.
:
They may charge you a fee but it will be done correctly.

Well, the "cheapest" way is what was suggested - try replacing any old/cheap splitters and cables/connectors first and see if that improves things.

said by nrobot80:

The Radio Shack and Amazon splitters and cable you buy may work but they may block your return path, which is essential for Internet access, and they may not be shielded to the point Comcast requires. Comcast wiring equipment is rated to block out noise and minimum signal loss.

If the OP uses the splitter models that were suggested (like the Antronix ones), they are as high quality (if not the exact same ones) as Comcast would provide/use.

Using an amp would be a last resort, but if so, it would need to be a "bi-directional" broadband cable one that provides a low loss in the 5-42 MHz return path.

said by chong67:

My modem stat is:

Downstream:
S/N Ratio: 37 db (4 channels)
Power Level: -1 dBmV

Upstream:
Power Level: 50 dBmV

While the OP's downstream power at his modem is good, the upstream level is very high, which could be due to the use of a poor-quality, first splitter that has a high loss in the return path. Replacing just that one could result in a major improvement.