Missing channels through Coaxial Network in the house

[ddonoh1001]

Hi,

I have a coaxial network in some rooms in the house. I've a Terrestrial Aerial on the balcony coming into one of the rooms upstairs.
I've connected the Coax cable from the Aerial to the coax network in one room and the tv to the other end in a room downstairs, I can only receive 8 of the expected 16 channels.
When I connect the aerials coaxial cable direct to the TV (ie bypassing the coaxial network in the walls) I get all the channels I expect.

What am i missing here? I've tried the TV in several of the rooms and still only 8 channels are shown. All 8 channels come through perfectly but the other 8 will not come through at all.

In the room where the aerial cable comes into the house, there is only one coaxial wire in the connecter in the wall but in the rooms where the TV is there are 2 (TV and Radio?).
I've tried connecting both cabels to the TV but get the same issue

Any ideas?

 

[kanewolf]

You are missing the loss (signal attenuation) that the splitter(s) are adding. Digital TV signals aren't like the old analog. They either work or they don't. There is no more "snowy" picture in a low signal case. The TV just skips the channel during the search. You would want something like this to boost the signal coming down from the antenna. You want this before the first splitter.

It is possible that you have low quality or damaged coax which is causing excessive signal attenuation. But the most likely candidate is just too many splitters or bad splitter(s).

Here is an article on video signal distribution. A little technical but it does have a lot of info. A signal strength meter would help with trouble shooting.

 

[ddonoh1001]

You are missing the loss (signal attenuation) that the splitter(s) are adding. Digital TV signals aren't like the old analog. They either work or they don't. There is no more "snowy" picture in a low signal case. The TV just skips the channel during the search. You would want something like this to boost the signal coming down from the antenna. You want this before the first splitter.

It is possible that you have low quality or damaged coax which is causing excessive signal attenuation. But the most likely candidate is just too many splitters or bad splitter(s).

Here is an article on video signal distribution. A little technical but it does have a lot of info. A signal strength meter would help with trouble shooting.

Hi Kanewolf,

Many thanks for your response - i did what you suggested, purchasing a Digital Pre-Amplifier which should have increased the signal by up to 20dB but unfortunately it did not work.
In fact, the signal for the channels that did come through was worse with intermittant breaks despite the connections seeming solid. I will see if I can order a signal strength meter to see what is coming through but in the meantime have you any other suggestions i can try?

 

[kanewolf]

Do you know if the channels you are missing are UHF or VHF channels? Do you know why the coax was installed (cable, satellite, off-air antenna)? The type of splitters used probably has something to do with your problem. If it was for cable, then there could be filters in the line somewhere. Is the coax along the outside or in the attic/basement?

 

[ddonoh1001]

I dont know if they are UHF or VHF - how would I find out? Not sure exactly why it was installed - when we moved in the network was in place in the house and I just connected the antenna myself recently.
The coax comes from an antenna on the balcony and is brought into the house from there. I connected the In port of pre-amp to the coax from the aerial and Out Port to the Coax connection in the wall with the TV downstairs.

 

[kanewolf]

I dont know if they are UHF or VHF - how would I find out? Not sure exactly why it was installed - when we moved in the network was in place in the house and I just connected the antenna myself recently.
The coax comes from an antenna on the balcony and is brought into the house from there. I connected the In port of pre-amp to the coax from the aerial and Out Port to the Coax connection in the wall with the TV downstairs.

This website can help you determine what over-the-air channels are available and what band they are broadcasting on. See if you can find some correlations with your missing channels...

 

[americanaudiophile]

There are two types of distribution systems. Here are some details that may help:
https/docs.google.com/viewer?url=http/www.atvresearch.com/techinfo/drop%2520tap%2520and%2520home%2520run%2520designing.pdf