Help on MoCA with Cable Amp

[streamerdreamer]

Hi All,

Reposting here to see if I can get some help...thanks!

********
MOCA with Amplifiers on line - no choice?

--------------------------------------------------------------------------------

Thanks to all for the many helpful posts.

I have a vexing issue that results from my cable setup and want to see if there are any options out there now to solve it.

Here's the deal: I have Comcast cable feeding a single coax into my basement. From there, it's split it into cable internet via a modem, and cable TV beginning with a powered amplifier, which includes a four way splitter box from which goes a bunch of TV cables all over the house. Performance on all of these has been ok until Comcast's digital "upgrade" (a topic for another thread...)

Anyway, several other lines (Cat5) lead throughout my house from the modem via a wired router, VOIP to Vonage, a switch, then later down the line, a hub, more switches, etc. and all works great from a speed and throughput standpoint. Amazing and has been for 10 years, even as we've added and dropped boxes and computers along the way, with only the occasional reset needed when reconfiguring and when Comcast service went out.

Enter MoCA: I wanted to use Netgear's new MoCA boxes (already purchased, of course) connecting over coax to my main living room TV and PS3 to stream video, store and stream pictures, get the internet to the main floor from the basement (believe it or not, we never put Cat5 cabling there - stupid!), and if possible, set up a wireless router with better broadcast quality from that point, and/or maybe use a second router as a bridge. Bottom line, the connection via currently installed coax to my TV doesn't work no matter what I and my very technically inclined buddy have tried.

It's the amplifier used for cable. That's pretty clear, as with one, all my TV's work, and without it, they don't. I followed the in-order setup directions, but even if I put my "old" amp only on a split line off the direct cable line to my TV in the LR, then there still isn't strong enough of a signal to drive the STB in that room. If I put the amp in the mix, MOCA won't get a coax light and no internet to the living room. As an update to this earlier post, I bought a bi-directional amplifier for my cable from Radio Shack, still no coax light on the Netgear MoCA box...

I knew going in that amps on cable might cause problems, thus have tried to configure the system through the software, and now through different wiring/splitters, etc., plus searched exhaustively for the right amplifier, knowing that Netgear points out amplifiers can't be used between nodes (unless they bypass the MoCA frequencies), but I MUST have an amplifier to power all these TV cable runs, and my MoCA is along one of these runs. That's why I picked up the Radio Shack bi-directional amp a few days ago. Still no luck. Best of all (not) Comcast techs (I've talked to several) don't even know what MoCA is, though they are a key sponsor of the alliance!!!

Please, before I throw these things back 'cause I want to love them...what can I do? Anybody else have this problem and solve it?

Oh I wish I was a coax network streamer...that is what I truly want to be...

 

[merc]

It sounds like the amplifier and the splitter are one unit. If that's the case, I would test to see if you're able to use the netgear boxes first without the amp to see if they're the problem. In your basement, disconnect the coax run to your living room and connect it to one of the netgear boxes. Then go to the living room and check to see if cable really is out, then disconnect the coax from there and connect the second box. Wait a few minutes and see if the coax light turns on.

If the two units connect just fine, you'll have to reconfigure your cable a bit. Just use a normal splitter (one that goes to 2GHz) and connect it between the amplifier and the coax run to the living room. Hook everything else up and test to see if it all works. Check for the coax lights on the netgears and check your tv for your cable channels. If you have digital cable, check to see if all those services work as well.

 

[streamerdreamer]

Thanks, Merc. Have been working on some other stuff so didn't see your reply 'til just now.

Will try your suggestion, but may have already...we'll see!

SD

 

[somec]

bypass amp with diplexers

You need to get the MoCA frequencies pass the amplifier while still having your original cable tv frequencies amplified. In order to do this you can just go to your local hardware store and pick up two Diplexers which cost around 3 bucks a piece and 3 very short peices of coaxial cable. If your not familiar with what a Diplexer is it is very similar to a splitter but the key difference is that it filters frequencies. For example instead of acting like a splitter and just making two connections out of one, it also seperates the frequencies to each connection. I have an IDEAL Diplexer I purchased from Lowes. It splits frequencies 5 - 950mhz (Digital Cable) on one end and then the other has frequencies 950mhz - 2300mhz (used for Satellite TV or in this case Moca). So from here what you would do is just connect the incoming coaxial cable into the diplexer first. From there you will have one of the 3 short coaxial cables going from the Digital Cable frequencies to the amplifier. The Moca/Satellite TV frequencies will be sent around the amp using another of the short coaxial cables. Then using another Diplexer on the other side of the amp you can combine the frequencies again simply by using the second Diplexer in reverse.

This should work out. You dont need the Moca frequencies to be amplified in order for them to reach your tv and ps3. It should be strong enough. Hope this helps

 

[wolfen281]

Possible diagram of solution?

Hi...I have the same problem, but I'm having a wee bit of a hard time visualizing the solution...anybody have a diagram of the diplexer answer?
Thanks
Kim

 

[wolfen281]

I found one.

 

[cspackler]

Question re use of Diplexer

I am installing a Comcast Multi room DVR but have all Coax feeding into an OnQ 3 x 8 CTAV amp/splitter in a data/TV closet. As I understand this discussion I can install the diplexers inside that cabinet? is that right? Thx.

 

[elatedBuilder]

You need to get the MoCA frequencies pass the amplifier while still having your original cable tv frequencies amplified. In order to do this you can just go to your local hardware store and pick up two Diplexers which cost around 3 bucks a piece and 3 very short peices of coaxial cable. If your not familiar with what a Diplexer is it is very similar to a splitter but the key difference is that it filters frequencies. For example instead of acting like a splitter and just making two connections out of one, it also seperates the frequencies to each connection. I have an IDEAL Diplexer I purchased from Lowes. It splits frequencies 5 - 950mhz (Digital Cable) on one end and then the other has frequencies 950mhz - 2300mhz (used for Satellite TV or in this case Moca). So from here what you would do is just connect the incoming coaxial cable into the diplexer first. From there you will have one of the 3 short coaxial cables going from the Digital Cable frequencies to the amplifier. The Moca/Satellite TV frequencies will be sent around the amp using another of the short coaxial cables. Then using another Diplexer on the other side of the amp you can combine the frequencies again simply by using the second Diplexer in reverse.

This should work out. You dont need the Moca frequencies to be amplified in order for them to reach your tv and ps3. It should be strong enough. Hope this helps

I made an account on this forum just to say how useful Somec's advice was! The solution with using two diplexers to circumvent the satellite signal (which is used by Moca, which most amps unintentionally block) around the CaTV amp worked perfectly. I was incredibly relieved when everything worked after I replaced the splitters with 5-2.4ghz splitters and used the diplexer-amp bypass. Thank you Somec!

To others with the same problem, here's an outline of what I did; the diagram linked by another user above is useful for learning about diplexers but seems to be a FIOS type of connection, not a Comcast / cable one.

Each line is one continuous wire connection:

Main Cable line -> 1stDiplexer -> CaTV (5-860 or 900mhz) line -> 5-1000mhz Amp -> Dip-CaTV (5-860 or 900mhz) line -> 2ndDiplexer -> re-united cable line

1stDiplexer -> Satellite (900 or 950-2100mhz +) line -> (longer cable) -> Satellite (900 or 950-2100mhz +) line -> 2ndDiplexer -> re-united cable line

If you're still having trouble, just try drawing it out on a piece of paper. Each diplexer has one wire coming in which is the entire coaxial signal (~5-2500mhz), and two going out which are the CaTV signal and the Satellite signal. The CaTV signal needs to go through the Amp in most homes to keep the signal from degrading over long cable distances, but the Satellite signal (our Moca signal!) needs to bypass by going from the Satellite plug of the 1st Diplexer to the same plug of the 2nd Diplexer.

On shopping from Diplexers: I was having a hard time finding the right device locally for a good price (Radioshack charges $22 a piece for theirs, which is RIDICULOUS), until I called a local Satellite TV company. I asked if they sold diplexers and they said yes, just $10 a piece. Walked in with $20, walked out with two Diplexers going from 5-2150mhz and the assurance I could come return them that same night if my plan didn't work. Brilliant and way easier than driving all the way to Fry's in rush hour traffic! I could have ordered them online, but I didn't want to wait until next week to solve this problem.

An additional note: make sure to look at your home setup and figure out which splitters you have, if they're 5-2400ghz or some such high-end value. You'll need to replace any splitters which the cable signal will go through to reach your Moca device--it's not too expensive, maybe $6-12 per splitter depending on where you go to shop, how many splits, and what quality you get. Personally I spent the few extra bucks for the higher-end gold-plated splitters because I wanted as little signal degradation as possible, but in the end it's only about $4 difference. If you can get ones which start at 5mhz and say "power pass" on them, all the better!

Final note (sorry, I'm just knowledge dumping all the stuff I learned over the last few days): make sure to get the RG-6 Quad Shielded coaxial cable, otherwise you'll be in a lot of pain. They're pretty common, having a thick wire because of all the shielding and insulation inside.

Again, thanks to Somec for pointing out this solution!