Saturday, February 23, 2013

Can You Run OTA Antenna TV and Internet Feeds on the Same Coax Cable? Yes!

So far we’ve cut the cable TV cord and maximized our over-the-air (OTA) antenna reception for our TVs; however, if you're like me, there's a snag with sharing the antenna's signal with a TV that also depended on one coax (that's a coaxial cable if you're new to these procedures) to provide cable TV and the Internet feed.  Fear not, for I would not lead you astray and will show you the way.  This is the third chapter in this OTA adventure, so in case you missed what has been covered so far, here's a recap:

Chapter 1 - Receive HD channels on your TV with an over-the-air (OTA) antenna

Chapter 2 - Optimize the antenna signal for all TVs with splitters

Chapter 3 - Run an antenna's signal on the same cord as your Internet feed

Chapter 4 - Stream videos from cable stations with a media server

When my cable TV was installed, a coax was run from the cable box on the bottom floor to the upstairs TV, which is where my main antenna is now located.  When I went about maximizing my reception, I wanted to use the coax installed by the cable company to feed the signal from the main antenna upstairs back down to the single coax connected to the downstairs TV.  The problem was that the coax from the cable box to the downstairs TV was still being used to connect me to the Internet (you only need one coax to run cable TV and the Internet).  Because cable TV and the Internet feed use the same signal, a simple splitter is all that's needed to give the TV its channels and your Internet router its Internet data.

Life does go on after you stop subscribing to cable TV, I promise.

The fix in my head was to combine the main antenna's signal with the Internet feed on one coax...if that was even possible.  I did lots of research on audio/video forums to see if this was possible and almost everyone said it was impossible.  Most said that you could not run the two different signals on the same coax because they run at different frequencies, there’s an issue with interference, and the gods would not allow it during the summer solstice.

However, I found one person who said you could use a device called a diplexer.  It sounds ominous, but really it’s friendly once you get to know it. It took plenty of research to confirm that a diplexer would do the trick so let's hope you found this blog in less time than it took me to learn about diplexers and type this entry.  Here’s how I used to diplexers to help cut the cord and solve this problem; your setup may differ, but the concepts still apply.

I should stop burying the lede…to run an OTA signal on the same coax as an Internet feed, use one diplexer where the signals combine onto one coax and one diplexer where you want the signals to split again from that single coax.

Step 1 - Return to your sketch in chapter 2 of the optimal setup for your OTA signal, now knowing that you can run the OTA signal on the same coax as your Internet feed. Recall that using one antenna’s signal on multiple TVs does not decrease the video quality even when they’re all on and showing different stations.

 In my case, the "satellite antenna" is the Internet service provider's feed to the house, the red line is the single coax that carries both streams, and the "satellite signal" is the Internet feed that finds its way to the router. 

Step 2 - One diplexer is needed to combine the antenna signal and Internet feed and another diplexer is necessary to (re)split them. Diplexers look like splitters and have all female ends just as splitters do. Go online or your electronics store and purchase your diplexers and connectors as necessary, holding onto that receipt just in case this whole experience fails. 
Step 3 - With your diplexers in hand, setup your main antenna and run its signal down to where you want to combine it with the Internet feed. It's okay to use a splitter anywhere in the feed’s path, no matter how far from the combination point, to reach other TVs before the fancy combining happens.

Step 4 - Go where you want the antenna’s signal to combine with the Internet feed.  Based on my story, this was outside on the first floor because of where the Internet (and cable TV) box was located.

Step 5 - At the combination point, you should have a free hanging coax with a male end that finds its way back to the main antenna.

Step 6 - Take one of the diplexers, we’ll call it diplexer A, and locate the side with two connectors (the bottom side in the picture above).

Step 7 - Screw the male end of the coax from step 5 into one of the bottom side diplexer connectors, the side with more than one connector on it.

Step 8 - Unplug your router (and modem if you have one).

Just one word: diplexers.

Step 9 - Locate the box that pulls the Internet feed into your house, this is probably the same as what was/will be your cable TV box.

Step 10 - Connected to the Internet box is a coax that runs into your house and is split with a familiar looking splitter.  Disconnect this coax from the splitter, or closest connection point to the box, leaving the other end of the coax connected to the Internet box.

Step 11 - Take the free hanging Internet feed's coax (and its male end) and screw it into the other “IN” female connector of diplexer A.

Step 12 - At the combination point, you now have diplexer A being fed the signal from the main antenna and your Internet feed.

Here's my setup proving something, I'm just not sure yet.

Step 13 - Locate the coax that runs into your dwelling; one end should still be screwed to the splitter that was connected to the Internet feed's coax.

Step 14 - Unscrew this coax from the splitter.  Congrats, you’ve got a free splitter from the cable company!

Step 15 - Take this same coax and screw it to the “OUT” female connector of diplexer A.

Step 16 - If all is well, diplexer A still has the antenna coax and Internet feed coax connected as inputs, and now has the coax that goes into your house connected to its output.

Step 17 - Take hold of the other diplexer, let’s call it, oh I don’t know, diplexer B.

Step 18 - Follow along the coax that goes into your house and locate its other end where you want to (re)split this super-mega-awesome combined feed.  In my case, the cable company setup a coax that ended with a splitter sending the signal to the TV and Internet router.

Here's my diplexer B in action.

Step 19 - Connect this main coax to the “OUT” female connector of diplexer B (it's the lonely port in the picture above, you can't miss it.  Well I guess you could miss it, but then this whole thing won't work well).

Step 20 - From the indoor splitter near you, unscrew the coax connected to your home's Internet router and then unscrew the coax that connects to your TV.  Again, you're removing them from the splitter and not the router or TV.  The router and TV will keep their coaxes attached.

Step 21 - Locate the coax that runs to your home’s Internet router and screw its free end to a connector on diplexer B with multiple connectors (bottom of the picture above).  In the pictured diplexer, the bottom connectors now become "OUT" connectors and the connector that's alone on one side becomes an "IN" port.

Step 22 - Locate the TV’s free coax and screw it to diplexer B’s other “IN” or “INPUT” port.  If you want to run multiple TVs from this feed, connect a splitter to this port on diplexer B and connect TVs from there as usual.

Step 23 - Turn on a TV connected to the diplexer and see if you receive signals as done in Chapter 1, step 19.

Step 24 - Any luck? If so, high five yourself, I may have been speaking the truth afterall.

 Don't forget the importance of cable management, keeping them bound and tidy.

Step 25 - Turn on all TVs receiving the main antenna’s feed and see if they receive channels too, setting them up as necessary.  Pretty cool how you can watch different channels on each TV at the same time, right?

Step 26 - Plug in/turn on your Internet router and let it reconnect to the Internet; then plug in/turn on your modem and let it reconnect to the router.  These devices should reconnect to the Internet on their own.  If you see lots of lights flashing in good ways then we’re doing alright.

Step 27 - Find yourself a device that connects to the Internet and see if it can connect. Any luck? If so, give yourself two high fives! You may now have every TV tuned to different channels while streaming Internet video without any issues on any of them.  As with any antenna signal splitting, channel reception is tied to the quality of a single antenna, but it should have been placed in a location that nullifies this issue.

Step 28 - Congratulations! You are now running the OTA antenna signal on the same coax as your Internet feed, have maximized the signal for every connected TV, and can wow people at your next cocktail party by saying things like, “I spent the weekend working with coaxes, splitters, and diplexers and I’m awesome.”

In the fourth and final chapter, I’ll talk about replacing some of those cable channels you used to watch by relying on a media player and streaming video.


PK said...

Thanks for your post. I will try this set up. We get phone and internet thru cable but want to discontinue the TV cable and connect OTA. I wonder if that would work.


Anonymous said...

OM -

This solution did not work for me...

Anonymous said...

What happens if you don't split it back out? So, for example, I would be combining the antenna and internet in my attic. I would then have two rooms where I would separate it back out to antenna for the TV and internet for hard wiring blu-ray players that can't get wifi. In the rest of the rooms I would just have TV's to plug in and wouldn't need the internet. Would I need to have a diplexer to separate the antenna back out in that room or could I just plug the coax directly in and it would read the antenna while ignoring the internet?

Anonymous said...

We're going to try this out as well, however I'm concerned because "everyone" says cable internet and OTA run on the same frequency. Can the cable company install a filter to filter out their TV signal, hence eliminating the interference? It didn't sound like it was necessary in your case. Any comments?

JP said...

Didn't work for me. Seemed Comcast in Seattle area are using the same frequencies as the OTA. I was able to get TV channels but not the internet feed. I'm subscribing only to internet. I checked to see if Comcast did put in a filter to block TV signals by turning on TV and running on Comcast line only. I got no signals. Wondered if there's a special diplexer to separate Comcast from OTA specifically if that's possible?

Anonymous said...

He is using a sattelite signal, not a cable signal from comcast or verizon /frontier / charter etc... I was told it will only work with satelite which uses a different signal.

barristerwa said...

Like JP, it didn't work for me and I also am in the Seattle area with comcast internet and TV. I want to cut the TV and just use the OTA. For 1, the picture is so much better from OTA. No compression and no pixelation.

Freddy Flow said...

Ain't gonna work with Comcast (apparently). Just got off the chat with them, here's what transpired... read it and weep...

Fred: I have Comcast Internet but not Comcast cable TV. I have an OTA antenna for my TV. There is a diplexer that splits the signal from the coax--one to the Comcast modem, one to my TV. Over the last month, I suddenly cannot get any OTA TV.
bocar: Fred, as I check the account, as what you have said you don't have a cable service. I apologized that this is not related with the service you have with Comcast.
Fred: Right, but it's related to the Internet service that we have.
bocar: Since you don't have cable service, the Diplexers will interfere the signal that your tv will be getting.
Fred: But that's what the installer put in when he installed the Internet service.
Fred: did something change with Comcast recently--because it used to work fine.
bocar: Please allow me 3 minutes to check the account further information and to check any documentations about the Diplexers.
bocar: As I check the account no documentation about the diplexers.
bocar: But Fred, we are encrypting our Limited Basic channels, which will result in the scrambling of those signals. As a result, a digital device is required on every TV in order to unscramble the signals and permit you to view your services.
bocar: Encryption encodes programming so that individuals cannot view it without authorization and payment.
bocar: In addition, encryption allows us to automate certain system functions and will reduce the need for scheduled in-home appointments, providing greater convenience for our customers.
Fred: Ok, but I don't have Limited Basic, I just have an antenna.
bocar: Yes Fred. The Limited Basic usually consist of local channels.
Fred: Right.
bocar: Those channels you have before are part of the signal leakages.
Fred: ok, so how do we fix this?
bocar: For this issue, I apologized in behalf of the company.
Fred: thanks
bocar: Yes Fred, the only option that we can do is to subscribe with the cable service.
Fred: how much does that cost?
bocar: Let me check on that Fred.
bocar: Please stay online.
Fred: so, but why did it work before, and not now?
bocar: Because of the recent encryption, there are no longer free channels available through the Comcast line. Each house would need a subscription, and a digital device to get the channels, even the local ones.
Fred: when did this happen? Why was there no notification?
bocar: The Limited Basic is about $18 to $25 per month.
Fred: I am not willing to pay for something that I should have for free.
Fred: I would think the very least that Comcast could do would be to send a tech out to install a second coax that would work to receive the free channels.
bocar: The encryption was made recently and for the exact date when, I apologized but I don't have the axact information.
bocar: exact*
bocar: I really apologized in behalf of the company for the inconvenience for the recent changes.
Fred: To repeat, I would think the very least that Comcast could do would be to send a tech out to install a second coax that would work to receive the free channels.
Fred: I'm paying almost $120 a month for Internet/phone--I would think that Comcast could at least provide a tech to reinstall the line, at no charge
bocar: I apologized for this Fred, but we cannot send a technician to add coax for you to get free channels.
Fred: Would you prefer that I cancel my service? Because that's what I'm thinking...
bocar: Please allow me a minute or two to check it with my head if we could do it.
bocar: Fred, as per advised we cannot do with the request to have the free channels back on your end. The option is to subscribe with the service for you to get the channels again.
Fred: no thanks. Good night

Anonymous said...

I install and service CATV systems for a living and I guarantee you this will not work at any optimal level.

First of all, you lose signal with diplexers (what you're using to combine antenna/internet.

Second, OTA antenna operates on about 50-500MHz and internet generally operates around 700-900MHz so theoretically you can combine them but you need to make sure the signal frequencies are in fact separate in MHz. Some systems run their data/internet as low as 100-150MHz so for these people there is no way they could combine these two signals.

Third, no one should buy splitters/diplexers from Radio Shack, they are garbage. If you want to do it right get Antronix/Extreme Broadband passive devices or at least Ideal (at home depot).

Due to these factors it's really best just to run two separate lines for your antenna and internet. This way you don't have to kill signal on either one.

Anonymous said...

Thanks for this blog post. My OTA antenna goes into an amplifier and then into a splitter which sends it into multiple rooms upstairs. So, doe the diplexer happen before or after the amp?

B and T Crowd said...

Re: Anonymous from Dec 2, 2013...Thanks for your professional tips on diplexers. I bought mine from Radio Shack simply because it was close should I need to return items. The internet and TV signal in my house continue to work with this setup. I suppose I'm the fortunate one, but I'm not sure why I'm lucking out if it's not supposed to work. You're right; the idea of running two lines would really be awesome in the long run.

Re: Anonymous from Jan 3, 2014...did you have any luck with the splitter before or after the amp? I'd guess that you'd want to place it after the amp so that the signal is secured, if you will, and then sent around your house.

Anonymous said...

If you do this and your internet stops working properly you will be charged about $60 for a tech to come out and tell you not to use equipment that's not provided by your cable company. Further more they are not going to work with you on trying to make this work and you run the risk of being disconnected by your cable company because you will be sending ingress/interference back on their plant that will cause issues for other customers( RF travels in all directions so even a diplexer combiner sends RF back to your cable provider and they don't want this). So save yourself some time and money and just run a separate line for your antenna. How do I know this? Only 9 years of experience at working for a major cable company. Once again if you have any issues and a tech comes out and sees any equipment besides what his company uses to install the service you will be charged for that visit. Remember an RF antenna does not just pick up certain frequency ranges, it picks up EVERYTHING. Radio, CB, TV, walketalke, cellphones, even RF from the sun and space etc. That is noise the cable company does not want.

Anonymous said...

In retrospect, I should have known this wouldn't work. I ordered the diplexers anyway, in desperation.
The fact is, that the cable company is running TV and internet through the same splitter and the splitter is rated at 5-1000 MHZ. So how could the internet be separated to run through anything rated above that frequency? It can't.
Before I tried this, I had to verify that running the antenna and internet together wouldn't work. The antenna signal is fine, but it kills the internet.
I ended up running a separate cable.

attrezzo p said...

As the experts have pointed out this isn't a one-size fits all proposal. However, another way to accomplish this is using MoCA adapters. The solution gets a bit more expensive but it basically goes, Cable Internet to Modem -> Modem to Ethernet -> Ethernet to MoCa -> MoCa to your household coax. Then on the antenna side. Antenna to MoCA filter -> MoCA filter to household Coax. MoCA, like satellite, operates on 1ghz+ frequencies well outside of the range of OTA tv. The MoCA filter will strip out the MoCA range noise from the OTA antenna so the signal stays clean in your household coax. If you have signal issues you'll want to add an antenna amp on the house side of the MoCA filter. That is Antenna-MoCAfilter-Amp-Household coax.

Please post back if that doesn't sound right.

For frequency reference.

attrezzo p said...

As an aside, a little history lesson.

OTA has been around since TV was invented. Shortly after that cable was introduced as a way to deliver better OTA signals to houses along with (eventually) premium channels. At this point it was all analog, so you had one or the other. Never both because they didn't travel over the same medium. One was in the air and the other ran through physical cables. Satellite came along and HAD to use higher frequencies because it went over the air as well. This translated into just dumping it on already run household coax to get the signal to set top tvs. After that security started and everything went digital, and finally internet. So the internet was really set up as an afterthought and isn't really on a defined frequency. Cable companies can (and do) put it wherever they want. Because of digital signals it really doesn't matter where they end up going, as long as your receiver box can translate to a "channel" they end up dumping internet traffic wherever it's most convenient. For some of us that's 800mhz+ and others it's 150mhz.

Charlie said...

I have Comcast in Denver and was thinking along similar lines: I have one cable coming in with internet, and I want OTA TV.

If there's broadcast TV on this cable, I want to use it with minimum disturbance to the modem. I'll assume for the moment that there is.

Cable providers have separate frequency ranges for upstream and downstream:

Upstream: 5 MHz to 42 MHz
Downstream: 42 MHz to 1GHz

This will complicate separating cable internet from TV based on frequency. More on that later.

A few things about TV:

- TV (since moving to digital) has “subchannels” (“7” became “7.1”).

- A group of subchannels sharing a major channel number is typically multiplexed on the same digital signal (but not always!).

- A signal has a 'real' (RF) channel. Each subchannel has a 'virtual' (PSIP) major and minor channel number. (PSIP is a standard for attaching metadata). A subchannel's major channel number may match the RF channel but in my area they're nearly always different.

- Stations seem to be moving from VHF to UHF. Maybe to free up VHF for non-tv use?

- The same subchannel numbers can be shared by media streams broadcast on two (or more?) different RF channels. In my area, channels 7 and 17 appear to be simulcasting identical content, subchannel for subchannel. The Wikipedia entry for KZCO-LD says:

“In 2013, KZCO signed on a digital signal on UHF channel 17 to serve as a fill-in translator of KMGH-TV, which has experienced issues with signal reception in portions of the Denver market since the June 12, 2009 digital television transition due to that station operating its digital signal on VHF channel 7, which is prone to signal interference.”

(What will a device do if it picks up two different signals for the same subchannel number? Just pick one of them? Can it assume they'll have the same content? I'm curious.) or provide station listings given an address.

I'll remove ones on the edge that are foreign language, televangelism, or in the VHF band with a UHF replacement. The resulting lineup:

By virtual major channel number:

2: The CW
4: CBS
6: Rocky Mountain PBS
7: ABC
9: NBC
20: MyNetworkTV
31: Fox

By 'Real' RF channel:

17: ABC
18: Rocky Mountain PBS
19: NBC and MyNetworkTV
32: Fox
34: The CW
35: CBS

Frequency Range: 488.31 MHz to 596.31 MHz

My cable modem (using DOCSIS 3.0) shows which channels it's using:

Upstream Channels 12 - 9 (17.3 MHz - 36.5 MHz)
Downstream Channels 6 - 15 (585 MHz - 639 MHz)

Two stations are keeping this from being a clean separation:

- KWGN-TV (The CW) on ATSC Channel 34 at 590.31 MHz
- KCNC-TV (CBS) on ATSC Channel 35 at 596.31 MHz

Only DOCSIS downstream channel 6 is in the middle of the tv channels that matter. The others ones (9-15) are above those tv channels. To stay with the “separate the frequencies” idea, let's say we sacrifice downstream channel 6 for the sake of The CW and CBS.

So here are the frequency ranges I'd like to carve up:

< 42 MHz
Upstream data for cable modem

42 MHz - 470 MHz
Don't care. Ideal cut might be at 42 MHz

470 MHz - 600 MHz
Stations for TV tuner(s)

> 600 MHz (Ideal cut might be at 602 MHz, the top end of RF channel 35)
Downstream data for cable modem

So... is there a device that passes frequencies below 42 MHz and above 600 MHz to one terminal and frequencies inside that range to the other? A sort of diplexer / triplexer? Or one with other numbers that work for the scenario above?

Or, is there a device like this which is adjustable in terms of the frequencies?

Finally, returning to the original question, can a cable actually carry broadcast tv signals such that cable signals won't “leak” out over an antenna, and the broadcast channels won't put noise on the cable system outside the building? Perhaps not, in which case all of the above may be futile anyway. I'd be interested in the answers to these questions, if anyone can shed more light on them.

Martina Salvador said...

Thanks for your post. We will try this set up. I just like to confirm if this also applies to the multidirectional antenna? Mys brother install that type f antenna in our house in province. And, he really happy to the result he get from buying that antenna.

Anonymous said...

I wish I would have read all the post before spending time and money on this. I have Charter and this would not work for my system. I will have to go through the aggravation of running another coax cable out to my antenna so I can drop the overpriced TV service. Basic TV from charter is $59 plus however many boxes you need for your tv's.