# moca filter question



## marklyn (Jan 21, 2002)

I have a moca filter (POE filter) installed between my 3 way splitter and outside cable.
I bought two moca filters though.

Can I or should I put the other moca filter between my cable modem and the splitter as well? Would it help or possibly hurt anything?


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## tatergator1 (Mar 27, 2008)

As long as the only thing fed by that line is the modem, you'd basically be shielding your modem from the MoCA network. I don't think it would effectively do anything good or bad. Worst case, that POE filter fails for whatever reason in the future, and it could kill your internet access until removed.


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## dswallow (Dec 3, 2000)

Unless you are trying to completely isolate some part of your in-home cable wiring from any subset of MOCA devices, the one and only place you want to install the filter is on the main cable feeding your home, prior to any devices you are connecting to the cable.


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## Loach (Jan 11, 2013)

dianebrat said:


> There's no reason to install a 2nd, the only place there should be one is the entry point of the cable line into the house.


At least one cable company disagrees with you. Cox in my market recommends isolating cable modems and tuning adapters from your MoCA network and actually provides a POE filter and splitter for free with their tuning adapter kit for the purpose of doing so.

I think Cox has had some trouble with MoCA causing interference with some older cable modems. I have POE filters on the input side of both my modem and tuning adapter. No idea whether they're accomplishing anything, but they're certainly not causing any problems.


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## marklyn (Jan 21, 2002)

tatergator1 said:


> As long as the only thing fed by that line is the modem, you'd basically be shielding your modem from the MoCA network. I don't think it would effectively do anything good or bad. Worst case, that POE filter fails for whatever reason in the future, and it could kill your internet access until removed.


I don't have a specific need that I'm aware of in doing this other than isolating that coax line that goes to my cable modem/phone. I thought since I had an extra one I could use it there if it makes sense to do so.


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## nooneuknow (Feb 5, 2011)

dianebrat said:


> There's no reason to install a 2nd, the only place there should be one is the entry point of the cable line into the house.


Unless MoCA is in use, and you have devices that can not tolerate MoCA signals.

You made a very broad statement, without any specifics on where that statement applies, or doesn't. I prefer not to confuse others who may read such a thing, and think that "one size fits all".

MoCA Poe (Point of Entry) filters are not limited to points-of-entry at the main coax entry point of residences. They are to be used on any device that either can't handle having MoCA signal frequencies in the coax feed (causing device issues), or may have been designed to reject those signals, but the internal filter has failed (causing device issues).

Cisco STA 1520 Tuning adapters REQUIRE the same PoE filter as you'd use at the true Point of Entry, or they will not work correctly.

Many cable modems can be negatively impacted, if they were not designed to reject the MoCA frequencies, or the internal filter fails to work correctly, on ones that have one.

Almost any device connected to your in-home coax can either not have been designed to deal with MoCA frequencies, or have an internal filter issue.

Every tuning adapter that my Cox cable market issues comes with a "self install kit", with directions, illustrations, splitters, cables, and a PoE filter, to be used on the leg of the splitter going to the TA.

Since there are multiple type of MoCA (retail-consumer, MSO, and others), using multiple bands of frequencies, MoCA can be a real issue for anything not designed to deal with it properly (or that fails to).

In a home not using MoCA (at all), then the standard PoE location is the only one of concern. Otherwise, it's possible that strategic placement of PoE filters could be a necessary means to keep MoCA only going to devices that need it, and keeping it out of those that don't. It also can enhance the performance of a MoCA network (greatly, in some cases), by limiting where the signals can, or can't traverse between, or to.


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## marklyn (Jan 21, 2002)

nooneuknow said:


> Cisco STA 1520 Tuning adapters REQUIRE the same PoE filter as you'd use at the true Point of Entry, or they will not work correctly.
> 
> Many cable modems can be negatively impacted, if they were not designed to reject the MoCA frequencies, or the internal filter fails to work correctly, on ones that have one.


nooneuknow, would you suggest that I place my second POE filter where the coax feeds into my tuning adapter (STA 1520)?


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## nooneuknow (Feb 5, 2011)

In the time it took me to type up my prior post, I see a few others have also chimed-in.

It's always nice to see other forum member looking out for those who may think "one size fits all" advice applies to all scenarios (even if that wasn't the desired statement the advisor intended to make, and/or the parameters/specifics of the advice were simply unintentionally left-out).

I learn more about things like this nearly every day. I've also made some overly-simplified statements about such things.


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## nooneuknow (Feb 5, 2011)

marklyn said:


> nooneuknow, would you suggest that I place my second POE filter where the coax feeds into my tuning adapter (STA 1520)?


Yes. *Just be aware that using the TA's pass-through (in-line) connection method is not recommended*, even if you don't have MoCA in use (the internals of that TA's pass-through are not up to Cox's specs, thus the Cox-advised splitter method).

The filter can either be connected to the output leg of the splitter that goes to the TA (Cox recommended setup), or placed on the input port of the TA (an alternative placement that should work just as well).

Just make sure not to place it on the input port of the splitter, unless you definitely don't use MoCA on the TiVo.


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## marklyn (Jan 21, 2002)

nooneuknow said:


> Yes. *Unless you are using the pass-through (in-line) connection method*, which is not recommended, even if you don't have MoCA in use (the internals of that TA's pass-through are not up to Cox's specs, thus the Cox-advised splitter method).
> 
> The filter can either be connected to the output leg of the splitter that goes to the TA (Cox recommended setup), or placed on the input port of the TA (an alternative placement that should work just as well).
> 
> Just make sure not to place it on the input port of the splitter, unless you definitely don't use MoCA on the TiVo.


I have a splitter in my a/v cabinet which splits one way to the Tuning adapter and one way to the Roamio Plus (which has MOCA turned on).
If I understand you correctly, it would be ok to place the moca filter right before the input to the tuning adapter.

Are there any known issues with this model tuning adapter being on a moca network? (ie: incorrect channel mapping, etc.), or is it just a 'good idea'?


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## nooneuknow (Feb 5, 2011)

marklyn said:


> I have a splitter in my a/v cabinet which splits one way to the Tuning adapter and one way to the Roamio Plus (which has MOCA turned on).
> If I understand you correctly, it would be ok to place the moca filter right before the input to the tuning adapter.
> 
> Are there any known issues with this model tuning adapter being on a moca network? (ie: incorrect channel mapping, etc.), or is it just a 'good idea'?


Yes, that should work fine.

Yes, there are known issues with that TA and MoCA frequencies. That is why Cox should have provided you with the free "self-install kit" that I mentioned, previously (which has a splitter, PoE filter, and a diagram). As long as you keep the MoCA signals from entering the TA, it will be immune to the known MoCA issues.


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## marklyn (Jan 21, 2002)

nooneuknow said:


> Yes, that should work fine.
> 
> Yes, there are known issues with that TA and MoCA frequencies. That is why Cox should have provided you with the free "self-install kit" that I mentioned, previously (which has a splitter, PoE filter, and a diagram). As long as you keep the MoCA signals from entering the TA, it will be immune to the known MoCA issues.


I'm actually on Time Warner, but thanks for the good info.


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## nooneuknow (Feb 5, 2011)

marklyn said:


> I'm actually on Time Warner, but thanks for the good info.


No problem.

I'm with Cox, somebody else was talking about Cox, so I guess I got my signals crossed. Likely, the Cisco STA1520 TA talk drifted me to thinking you were with Cox, since they use that model in many of their markets.

Anyway, MoCA is MoCA, with the only differences being the frequencies each flavor operates on.

Some of the MSOs (cable/phone/satellite companies) operate on frequencies inside their normal range that would come into the home, while retail equipment operates outside that range. The retail frequencies can punch right past splitters designed to constrict what frequencies get through, as well as the port isolation between the "out" ports. It can punch it's way right out of your home, and into your neighbors' homes. That's why the single most important PoE filter installation point is at the single coax that enters your home. It's good for you and your neighbors, regardless of who has MoCA and who doesn't. If you have MoCA and your neighbors don't, and you neglect to install a PoE filter, you can cause interference for their home devices.

The more heavily focused-on reason for making sure you have one installed at residential entry point is for security. This is kind of an old reason, as most current MoCA networks have enough security measures in-place to help keep your network, your network. That still doesn't keep un-filtered frequencies from punching into places it can wreak havoc, though.

I'll be around if you have any more questions. But, there are other threads that others started before you, where somebody who says they are a "retired RF engineer", who seems knowledgeable enough to back it up, has provided a great amount of great info, even helping bring me up to speed on facts and myths about how RF frequencies act and interact on a RF network.

I'd suggest you peruse them at your leisure, if you'd like to soak up some knowledge on the subject.

Good luck, and best wishes.


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## marklyn (Jan 21, 2002)

nooneuknow said:


> No problem.
> 
> I'm with Cox, somebody else was talking about Cox, so I guess I got my signals crossed. Likely, the Cisco STA1520 TA talk drifted me to thinking you were with Cox, since they use that model in many of their markets.
> 
> ...


Come to think of it, I do have one more moca filter question.

How can you tell which direction to install the moca filter on? One end is male and the other end is female (I'm not sure which is which). Or does it even matter?


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## nooneuknow (Feb 5, 2011)

marklyn said:


> Come to think of it, I do have one more moca filter question.
> 
> How can you tell which direction to install the moca filter on? One end is male and the other end is female (I'm not sure which is which). Or does it even matter?


It doesn't matter. Despite the two genders, it's not directional (unless it is clearly labeled otherwise, which I have yet to see an example of one existing). The end with the center hole is female, and the end with the exposed conductor inside is male.

If you want to go by the way Cox illustrates it, you'd screw it onto the splitter "out" port directly (leg that goes to TA). You could also just attach it directly to the tuning adapter "in" port. A good quality "barrel" connector (like what goes through a wall-plate) can be used as a gender-neutralizer, should you want to place it mid cable run. All that matters is that it is after the split and before the TA (and you don't use the "out" port of the TA for anything).


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