Issue Routing MOCA Around Cable Amp

[getnet]

New member. I've read all the MOCA and diplexer posts. I have a wonderfully working home MOCA network using four Actiontec MI424WR's. I don't have Verizon FIOS just regular cable TV.

Big screen in the living room needs the Signal Vision Subscriber amp 53-1000 MHz, Reverse Path 5-42 MHz to get a good picture on all channels. I put a satellite TV diplexer (5-860 MHz for TV, 950 - 3450 MHz for MOCA), in front of the amp to split the MOCA and cable TV signals, routing MOCA around the amp, then another diplexer on the other side to re-combine the signals on the way to the TV and MOCA box splitter. It doesn't work for the MOCA.

If I use one diplexer and don't include the TV signal I can get MOCA through so it's not a cabling issue or the diplexer but of course I'm not getting the TV signal. If add the second diplexer to recombine the signals MOCA quits working but TV is fine. I bought a different brand of diplexers and had the same problem. Any thoughts on what I'm doing wrong or debugging ideas?

Thanks.

 

[thiggins]

Need a diagram of your setup to properly diagnose what is going on.

 

[getnet]

Tim,

Thanks for the quick response. I'm a "hobbyist" at this stuff so please forgive any inadequacies in my network diagram. I've attached the file in .jpg format and inserted the image here.



Cheers,

Mike

 

[thiggins]

Thanks for the detailed diagram.

First, why do you have four routers (five if I count the "Netgear 4 port wireless router")?

Second, you have an awful lot of cascaded splitters. And any splitter that the MoCA signal passes through must be rated to at least 1.5 GHz, not 900 MHz.

Between the Actiontec in the Family room and the one in the Kitchen or other room, I count six splitters and /or diplexers. I suspect that there is just too much signal loss for the MoCA signal.

Try to bypass some of the splitters temporarily by moving a MoCA connection and see if you can get a connection.

 

[getnet]

Tom,

Sorry for the incorrect nomenclature on the diagram. There is only one router - Netgear 4-port. The rest are configured as MOCA bridges.

You were correct. It was problem with the splitter. I switched it out for another and it all works fine. I'm stoked! Thanks a bunch for the help.

One note though, you recommended the splitter be rated to at least 1.5 GHz. The splitter I had is only rated to 1GHz. It's working great as far as I can tell but what am I losing without the other .5 GHz? I can go out and buy a 1.5 GHz per your post if need be. What are your thoughts on why the 1GHz is able to work?

Thanks again for the debugging help.

 

[stevech]

I believe that commonplace MoCA products use frequencies less than 1GHz. The newer standard allows for up to 1.5GHz.
I may be wrong.

 

[thiggins]

One note though, you recommended the splitter be rated to at least 1.5 GHz. The splitter I had is only rated to 1GHz. It's working great as far as I can tell but what am I losing without the other .5 GHz? I can go out and buy a 1.5 GHz per your post if need be. What are your thoughts on why the 1GHz is able to work?

MoCA uses the 850-1550 MHz band. So it can work with splitters that pass only part of those frequencies (up to 1 GHz).

But you could find problems with using only 1 GHz splitters if you get a lot of simultaneous traffic across the MoCA bridge. More traffic requires more bandwidth, which requires MoCA to use more of its frequency band.

 

[stevech]

nit: I understood MoCA to be a fixed number of OFDM tones, similar to 802.11n. The modulation order (QAM-n) can vary by signal to noise (and interference), and thus the throughput. The occupied bandwidth is determined by the number of tones. Like 802.11 is 20MHz no matter the the throughput yield from variable modulation order and coding rate.

If I'm wrong, please correct me.

 

[thiggins]

nit: I understood MoCA to be a fixed number of OFDM tones, similar to 802.11n. The modulation order (QAM-n) can vary by signal to noise (and interference), and thus the throughput. The occupied bandwidth is determined by the number of tones. Like 802.11 is 20MHz no matter the the throughput yield from variable modulation order and coding rate.

MoCA is more like HomePlug. OFDM is used, but the # of tones / channels varies constantly to avoid interference and maximize bandwidth.

 

[circuitnine]

MoCA is more like HomePlug. OFDM is used, but the # of tones / channels varies constantly to avoid interference and maximize bandwidth.

So which one would you recommend? I am running a number of email marketing campaigns from home and have everything where I need it for the most part regarding the tasks assigned by my IT jobs administrator. I just need to ensure that my network and cloud set up have the ability to distribute mass quantities of data.

 

[thiggins]

MoCA if you have coax where you need it. HomePlug AV otherwise.

 

[stevech]

Yes, MoCA if there is TV coax at the two end points.

Advantage of MoCA over HomePlug AV is that MoCA does not have to cope with many noise sources on the home AC power wiring, and in the US, bridging across two-phases.

 

[thiggins]

Advantage of MoCA over HomePlug AV is that MoCA does not have to cope with many noise sources on the home AC power wiring, and in the US, bridging across two-phases.

Cross phase hasn't been an issue for a couple of HomePlug generations, as I have pointed out many times.

 

[stevech]

HomePlug...I've read on other forums that this may or has been an issue for some.
Technically, it is curious how the signal can propagate across the phases as in the breaker panel there is no path. Some 220VAC appliances may unintentionally bridge the signal. Or there's some explanation other than phantom coupling.

But perhaps I'm just incorrect.

 

[thiggins]

HomePlug...I've read on other forums that this may or has been an issue for some.
Technically, it is curious how the signal can propagate across the phases as in the breaker panel there is no path. Some 220VAC appliances may unintentionally bridge the signal. Or there's some explanation other than phantom coupling.

But perhaps I'm just incorrect.

My test locations cross phases and show no problems at all. I'll see if I can get you an "official" word from Atheros.

Et voila.

 

[stevech]

Thanks - I read the paper.
The premise is that a 220VAC appliance (or many) receive both phases and coupling between the phases occurs due to the wires to these appliances.

In many homes, there are no 220VAC appliances. And thus no wiring runs carrying both phases. My home is an example of such no-220 appliances and no runs to an unused 220V outlet. This is a generic 1990's era home with gas for heating and cooking and no air conditioner.

 

[thiggins]

So you'd be a good Guinea pig to see if HomePlug works for you.

 

[stevech]

Right! Someone will send me a pair?