# POE Filter kills Internet access



## LASchleigh (Jul 4, 2005)

I recently picked up a Roamio pro and Mini. I also picked up the MOCA adapter and POE filter from TiVo. I was having issues with my Mini being jumpy on playback or live TV. I read that a different splitter and POE filter could help. The splitter that was there was installed by the cable company and is a 5 - 1000 MHZ. I replaced that with a 5 - 3000 MHZ splitter I picked up locally and installed the POE filter. Mini now seems to be running smooth but I had no Internet access. Apparently my cable modem wouldn't connect. I removed the filter and now the modem connects and Internet access works fine. 

Here is my setup:
Cable comes to the house - POE Filter - 2 way splitter
1st line goes to the office to a Actiontec MOCA adapter then to Cable modem
2nd line goes to family room to a Roamio Pro.

With the POE filter, no modem connection and no internet access
Without POE filter, modem connects and have internet access

Anyone know if there a reason why the filter would kill my cable modem/internet access?


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## Dan203 (Apr 17, 2000)

This happens when the POE filter is defective. You should return it and get another one.


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## dianebrat (Jul 6, 2002)

Dan203 said:


> This happens when the POE filter is defective. You should return it and get another one.


POE filter installed backwards at the entry point will also do that... (as in after the junction not before)


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## lessd (Jan 23, 2005)

LASchleigh said:


> I recently picked up a Roamio pro and Mini. I also picked up the MOCA adapter and POE filter from TiVo. I was having issues with my Mini being jumpy on playback or live TV. I read that a different splitter and POE filter could help. The splitter that was there was installed by the cable company and is a 5 - 1000 MHZ. I replaced that with a 5 - 3000 MHZ splitter I picked up locally and installed the POE filter. Mini now seems to be running smooth but I had no Internet access. Apparently my cable modem wouldn't connect. I removed the filter and now the modem connects and Internet access works fine.
> 
> Here is my setup:
> Cable comes to the house - POE Filter - 2 way splitter
> ...


When I got my first POE filter I put on the cable coming into my modem and checked the speed, it went to zero, a bad POE filter, I was sent another and that one placed on the cable input of my modem had no effect on my internet speed, then I put that POE filter on my home cable input.


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## LASchleigh (Jul 4, 2005)

Thanks for the help. I will get a new POE filter and give it a try.


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## HDRyder9 (Aug 2, 2007)

Does anybody know if POE filters are directional?


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## nooneuknow (Feb 5, 2011)

HDRyder9 said:


> Does anybody know if POE filters are directional?


Unless it specifies itself as being directional (which I have yet to see), no, they are not directional.

Even if I had one work in one direction, but not the other, I would still consider it defective, if the manufacturer does not clearly spec it out as being directional.

What things matters most (with any possibility of directional POE filters existing, being put aside), when it comes to POE filters, are:

1. Being in the proper place(s) (being where it should be).

2. Using splitters of the correct specs (the frequencies being correct).

3. NOT using the pass-through (in-line) path through devices like Tuning Adapters, if they aren't designed to deal with accepting/rejecting/passing/blocking all frequencies existing on the coax.

4. The most important place to have a POE filter (even if you don't use MoCA), is BEFORE the first split takes place on your to-the-house (lateral) coaxial cable (for security reasons). Any other placement is merely to keep MoCA frequencies from causing unwanted interference within devices that can't deal with them (like Tuning Adapters), or to make different MoCA network segments within your home.

The latter "segmenting" is for advanced power-users, and/or people who might have differing types of MoCA supporting devices, who need one frequency band to only go to certain devices, and another frequency band to only go to other devices.

This can happen if you have BOTH MSO equipment on MSO equipment frequencies, and non-MSO (like retail TiVo) equipment on retail device frequencies, and/or if you deliberately set up devices on different frequencies.


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## dianebrat (Jul 6, 2002)

HDRyder9 said:


> Does anybody know if POE filters are directional?





dianebrat said:


> POE filter installed backwards at the entry point will also do that... (as in after the junction not before)


hint...


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## nooneuknow (Feb 5, 2011)

dianebrat said:


> hint...


That sounds more like a matter of being in the wrong place, as opposed to being in the wrong direction.

Splitters "split" (not technically, but that's a long explanation), otherwise they wouldn't be called splitters.

Having a POE filter before, as opposed to after, the "split", is not a directional matter. It's a "being in the wrong place" matter. Just because the same POE filter ends up in one direction, simply due to the placement of the female and male ports, does not a directional matter make.

I'm still standing by my statement that, until somebody can post a link to a POE filter's specs stating it is directional, as opposed to anything else, one that fails to work in one direction, but not the other, is defective.

How do you put one in "the other way around"? I'm so glad somebody asked (no, nobody actually did).

Here's how: Use a short length of Coax on one side to make the male-male aspect mate (a "gender changer"), then use a barrel connector on the other end as a "gender changer", so the coax on that side can connect.

Now you have reversed the male & female port orientation, reversing the directionality, without moving the POE filter from the same leg of the splitter (it remains in the same position, just flipped 180 degrees). I've seen Cox techs do this on more than one occasion.

Apply some logic, and think about port position (Is it on the entry, or exit? Is merely on a different leg on the "out" side of the splitter?). Logic would make it so POE filters would be a major hassle, and create more issues than they resolve, if their male & female ends couldn't be rotated 180 degrees, thus "reversing" them.

I'll wait to see if anybody can provide any proof that any sort of "directional" POE filter truly exists, as opposed to assuming they are directional, due to having male-female ports. If one surfaces, I will research it thoroughly, and make sure it truly is directional, then explain how to install (or not install) it, and where it would belong. Until then, I'll stand by over month of research on the matter, what I've been told (which I always research before I take as fact), and my own experiments/experience in determining whether there is any directionality in a *non-defective* PoE filter.


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## lessd (Jan 23, 2005)

nooneuknow said:


> That sounds more like a matter of being in the wrong place, as opposed to being in the wrong direction.
> 
> Splitters "split" (not technically, but that's a long explanation), otherwise they wouldn't be called splitters.
> 
> ...


The POE filters I have had can only be put in in one direction, unless you want to do a sex change on both ends of the filter. OK I guess if you put the filter after the splitter the direction would get reversed. But because when I install the filter I put it on the main feed cable coming into the home before any splitters it goes only one way.


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## nooneuknow (Feb 5, 2011)

lessd said:


> The POE filters I have had can only be put in in one direction, unless you want to do a sex change on both ends of the filter. OK I guess if you put the filter after the splitter the direction would get reversed. But because when I install the filter I put it on the main feed cable coming into the home before any splitters it goes only one way.


Yep. The simplest explanation of what I'm trying to say, in the scenario you describe, is that while you can technically install it only one way (when attaching directly to the splitter leg), due to Female-Male ends, it gets directionality-reversed by going on the opposite side (in or out side of a splitter), and in your situation, you could do that "gender change" with a barrel and some coax, and reverse the ends, while leaving it in the same place (position), just 180 degrees flipped, and whatever length of cable used, that distance away from the splitter. If there is nothing wrong with it, it will work the same, minus the small loss caused by the additional connections (insertion loss).

Perhaps, someday, we will see directional filters. I doubt it, but can't rule it out from happening, or that there may be some oddball one out there that already is.

I've seen Cox "test" them, using the barrel gender-change method, and if they operate differently, they throw them in the garbage. It's the same with every other kind of "trap" or "filter" they use. There is no right or wrong way, directionality-speaking, to install any of them. I'm sure this is by design, and likely costs more than making the same traps and filters directional. It likely makes up for the additional cost, by making it impossible to install in the wrong direction.

While I realize Cox has their own MoCA bands, and we are talking about retail PoE filters, the same ones Cox provides with TA self-install kits, can be purchased online, and can function fine with retail MoCA bands as well (when used in conjunction with the right splitters).

I think where some confusion creeps in, is the very existence of the male end (the one with the center conductor exposed), while all the other traps and filters are female on each end, requiring coax connections on each end. All it takes is a barrel connector screwed into the PoE filter to make both ends female, like all the others.


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## unitron (Apr 28, 2006)

If a filter is passive, i.e., made up of just resistors, capacitors, and inductors, I don't see any way it could possibly be directional.

It may be far from purely sinusoidal, but that's still an AC waveform going through it, which means it's reversing direction up to millions of times per second.


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## nooneuknow (Feb 5, 2011)

unitron said:


> If a filter is passive, i.e., made up of just resistors, capacitors, and inductors, I don't see any way it could possibly be directional.
> 
> It may be far from purely sinusoidal, but that's still an AC waveform going through it, which means it's reversing direction up to millions of times per second.


I pretty much agree.

It's just that there are some who insist they are directional. As I ended my last post with, *I think that the mere existence of a gender difference is leading people to draw a false conclusion that by having two genders it means it is directional*, thus can only be placed in one position, and are making arguments over which leg of a splitter it belongs on.

While "PoE" means "Point of Entry", it's yet another factor which confuses some. PoE filters can be used to isolate MoCA signals to only the equipment that needs MoCA, and keep those signals out of equipment that doesn't need them, or will operate improperly if those signals aren't filtered, and stopped from *entering* such devices. So, technically, it's still stopping signals from getting to a "Point of Entry", even though many seem to think the point-of-entry as only being the lateral cable to their home.

If the ones Cox uses and provides, were directional, and only meant for the residence point-of-entry, all the TA self-install kits would not only have wrong directions for placement, but also illustrate them being placed "backwards", going by the "logic" that keeps popping up in all the MoCA and PoE filter threads.


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## fcfc2 (Feb 19, 2015)

nooneuknow said:


> I pretty much agree.
> 
> It's just that there are some who insist they are directional. As I ended my last post with, *I think that the mere existence of a gender difference is leading people to draw a false conclusion that by having two genders it means it is directional*, thus can only be placed in one position, and are making arguments over which leg of a splitter it belongs on.
> 
> ...


Hi,
I have done several MoCA installations and have at times had to use MoCA filters on both cable modems and STB's to eliminate interference. I have also used at least 5 different manufacturer's products. None are directional. The confusion in part comes from the industry standard of placing a "red" band on one end of the filter, seemingly indicating a "direction" for installation and for most standard installations at the "Point of Entry" i.e., the input of the main splitter, this seems to make sense. However, in reviewing MoCA trouble shooting guides, a common problem is loss of internet as a result of interference to the cable modem and the recommended fix is to place a filter on the input of the modem. In this case, if the filters were directional, the filter would do nothing to stop the interference, because it is "backwards", but it does block the MoCA signals quite effectively. BTW, in a review of all available MoCA guides, I have never seen any reference to the filters being directional. MoCA FILTERS ARE NOT DIRECTIONAL.
EDIT: After re-reading the OP's original post, he mentions using an Actiontec router. I am guessing that he is on a FIOS system and if so, placing a POE filter on the input of the first splitter will in fact block the internet signal because FIOS uses coax/MoCA WAN to feed their router. You should never use a POE filter on a FIOS system, period. They are unnecessary because of the transition to fiber at the ONT.


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## atscntsc (Feb 26, 2011)

lessd said:


> The POE filters I have had can only be put in in one direction, unless you want to do a sex change on both ends of the filter.


While physical conditions may dictate which direction the filter needs to be oriented, there should be no operational restriction as to which direction it can be placed.

An example is when used with a grounding block with male threads on both ends. The POE filter can be positioned on either side of the grounding block. In fact, grounding blocks with POE filters incorporated may be purchased. One such model available is part number POEGB-1GCW manufactured by PPC. As evidence that direction is not important, the spec sheet for this part states:

"Ground block can be mounted in either direction (bi-directional)."

http://www.ppc-online.com/docs/MKTimages/upload/POEGB-1GCW_Spec_Sheet.pdf


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## Wiley1 (Dec 14, 2008)

fcfc2 said:


> in reviewing MoCA trouble shooting guides, a common problem is loss of Internet as a result of interference to the cable modem and the recommended fix is to place a filter on the input of the modem. In this case, if the filters were directional, the filter would do nothing to stop the interference, because it is "backwards", but it does block the MoCA signals quite effectively.


This is the best explanation I've seen anywhere.

I have a typical home network: grounding block outside, then a 1000 Mhz 2-way splitter where one side goes to my Comcast cable-modem and the other side feeds a 2000 Mhz 6-way splitter. Three of my Mini's are connected by MoCa and the 4th one is connected to the same gigabit switch that feeds my Roamio Plus. The Mini that is on Ethernet often pops up a message complaining that my network is too slow. (Can somebody explain why Tivo elected not to put a Gigabit adapter in the Mini?)

I know I need a POE filter, but where to put it?
1. I could put it between the ground block and the first splitter which would protect my entire network, including the cable-modem, from the outside world and prevent my MoCa signals from leaching into the neighborhood.
or
2. I could put it after the 2-way and before the 6-way which would protect my MoCa network from the outside world AND protect my MoCa network from my cable-modem AND protect my cable-modem from interference from my MoCa network. But, it would not isolate my cable-modem from my neighbors' MoCa signals.
or
3. I could use 2 POE filters, one on each leg of the 2-way splitter. This would isolate the MoCa network from everything AND isolate the cable-modem from everything. The only thing exposed to the outside would be the 2-way splitter.

I'm leaning toward Option #3.

Questions:
> Which of these three options will give the best performance on my MoCa network?
> Which of these options would Comcast prefer?
> Will any of these options degrade my cable-modem performance?
> Are any of these options likely to help with my "network too slow" issue on the Ethernet-connected Mini?


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## fcfc2 (Feb 19, 2015)

Wiley1 said:


> This is the best explanation I've seen anywhere.
> (Can somebody explain why Tivo elected not to put a Gigabit adapter in the Mini?)
> 
> I know I need a POE filter, but where to put it?
> ...


Hi,
I would recommend you try option #2 as it requires only 1 filter and reduces the MoCA run to your second splitter as well as eliminating the interference issue to the cable modem. 
Comcast shouldn't care one way or the other, but they would probably put it directly on the drop or the first splitter out of convenience to them.
Regarding the "network too slow" issue, even though the mini has only fast Ethernet, this should be plenty fast enough to stream video as none that I know exceed about 20Mbps. The issue might be an iffy Ethernet cord / connection as these problems manifest when under load. I would try swapping out the Ethernet cable with a new one and see if your problem disappears.


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## snerd (Jun 6, 2008)

I agree with the recommendation for option #2. If you do choose that option, attach the PoE filter directly to the input of the 6-way splitter in order to avoid attenuation of the MoCA signals in the coax the runs between the two splitters.

The coax between your house and your neighbors will attenuate their MoCA signals significantly before they reach your house, so interference with your cable modem isn't likely. Some cable modems (e.g. SB6141) have internal MoCA filters anyway.


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## Wiley1 (Dec 14, 2008)

OK. I will try it with just the one filter. I'll attach it directly to the input of the 6-way splitter, although I'm not sure why. Is it because of the filter's tendency to "reflect" the MoCa signal back into the MoCa network? 

I'm starting to suspect that my Buffalo 24-port switch isn't performing all that well. I am going to try putting the Roamio and the Mini directly into the LAN side of my Cisco RV180 router as a temporary test.

I may also be having issues with my Roamio being 3 hops from my router: 24-port, 8-port, and 4-port, all gigabit switches. Any one of them could be creating a bottleneck, I suppose. If this turns out to be the cause of my "network-too-slow" issue, I'm going to be pulling some long cable runs to some very awkward places in my home.


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## snerd (Jun 6, 2008)

Wiley1 said:


> OK. I will try it with just the one filter. I'll attach it directly to the input of the 6-way splitter, although I'm not sure why. Is it because of the filter's tendency to "reflect" the MoCa signal back into the MoCa network?


Yes, the MoCA filter reflects the MoCA signal back into the MoCA network. This isn't merely a tendency, most of the RF power that hits the PoE filter is reflected, as this is what the PoE filter is designed to do.


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