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Can't get any channels when diplexing OTA with cable.

852 Views 7 Replies 8 Participants Last post by  holl_ands



Hoping someone can help me!  I just got an RCA antenna, mounted it inside the roof of my garage, connected it to the coax cable running into my basement, then to the coax cable running to our living room TV. NO channels. Zero. Zip. I scanned for antenna, digital, and got nothing. 


I DID get 12 snowy channels when I searched for analog as well (which I don't understand at all because I know analog isn't broadcast anymore)..... but only once, and then I changed the connections and couldn't get anything anymore. 


I should mention as well that I wanted to use the same coax cable that my internet is running on, and therefore bought two diplexers for each end (one where the antenna and internet signals originate and one for the other end of the coax in the basement.  But when I hooked everything up, I didn't get any channels OR internet. It might be important to note that the time I got the snowy channels, I had the diplexers hooked up, but the internet not connected to the diplexers. 


The bottom line, to be clear, is that even when I just connect the antenna-coax-TV, I don't get any channels. TVFool says I'm within 10 KM of a station so I *should* get some channels. 


On the TV (brand new Panasonic Smart TV Viera), I go to the antenna settings, then auto program ALL .


Any ideas? I would be so grateful to find an easy solution....


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I would take the antenna to where the tv is and connect it directly to the tv and rescan. If you can get some stations then you know the antenna and tuner works. It could be the location of the antenna in the garage (too much interference) , the cable connection from the garage, splitting the connection, or maybe even the wrong type of antenna. I would go to TVFool.com, put in your address and see what stations are available to you. Then post that information in the Local HDTV forum for your area. You will get advice from folks in your area that can advise you on which antenna would work best for you, installation, etc.

Originally Posted by jukikee  /t/1519528/cant-get-any-channels-with-an-ota-antenna-and-panasonic-viera-tv-new#post_24400194

I wanted to use the same coax cable that my internet is running on

This suggests that you're getting your Internet from your local cable company. That cable probably also carries all their cable TV channels. Even though you're not using those channels, they're still on the cable and interfering with the signals from the antenna.

In general, you cannot mix antenna signals and cable TV signals on the same cable.
Topic title edited.

JTBell is right. You can't mix OTA with cable. They use many of the same frequencies. Not only will you not get any channels, but you risk wrecking cable reception for your neighbors, as well, as you've created a point of ingress into a previously closed system.
+1 on this is not possible !!!

You will absolutely have to use separate coax cable runs for anything on the cable plant and anything coming in OTA (TV/FM radio).. Anyone who has done any reading at all on this forum would see this immediately.
Since you were scanning for OTA channels (which are mostly different channelization from CABLE channels), you were only seeing the analog Cable channels on 2-13.

The Cable TV channels, as well as your downstream internet, are within a continuous band of frequencies from around 50, to as high as 900 MHz. The OTA channels are on three (or four, depending on how you look at it) bands.....2-4, 5 and 6, 7-13 and 14-51, scattered throughout the same frequency range.

No affordable way to mix the two, and you could be causing interference to most licensed services in your neighborhood.

Run a new cable.
What you CAN do is put a Wi-Fi ROUTER and the CABLE MODEM connected right at your CATV entry point, leaving the interior coax wiring DISCONNECTED. That will allow your computer(s) to use the Internet. If not already properly configured before being moved, you MIGHT have to configure the Wi-Fi ROUTER via a DIRECT Ethernet connection to your computer before using the Wi-Fi connection.
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