Saturday, January 23, 2010


A couple of weeks ago, we purchased a 40" Samsung HD TV (actually we bought two at the time - we picked up one for Derek's family at the same time). Thinking that I'd just hook up the current TV cable and have HD TV (after we purchased the correct package and rented two HD decoder boxes from Shaw) I found that this wasn't quite so simple. It turns out that we got next to no HD and digital channels on our side of the house. The regular TV channels which we had been getting before were still available.

The cause turned out to be an antiquated cable feed which was installed when cable TV first became available, and the original external splitter from which a couple of cables ran into the house. So Shaw installed new cables to the house from the pole across the street, a new distribution box, and two new cables from this box into the house (the installer did a neat job - those cables are barely noticable). This improved the situation somewhat for our side - i.e we got some HD and digital channels, but certainly not all of what we contracted for. Derek seemed to get all the channels on his side of the house - he uses a video signal amplifier.

Splitters take the incoming video signal and split it into two or three cable circuits for use with additional TV sets. This comes at a cost, of course. The signal coming out of each the splitter outlets is usually attenuated by 3 DB (more for cheap ones). Without getting into the mathematical details, this means that each loss of 3 DB means that signal strength is cut in half. If you have a couple more splitters "downstream" from the first splitter, you lose another 3 DB for each splitter. This can result in a very weak signal at the far end of the cable.

Since the above-mentioned original external splitter seemed to be at least partly responsible for the problem, I reconfigured the TV cabling on the inside of our side of the house to do away with all splitters on the way to the HD decoder box. Lo and behold, all standard, digital, and HD channels could now displayed on the HD TV.

We have several additonal (cathode ray type) TV sets on our house; the cable re-arrangement resulted in no signal to them. The solution turned out to be relatively simple. The HD box has a built-in bypass, which connects the incoming cable to an identical standard cable outlet, while at the same time feeding the original decoded signal through an HD cable to the HD TV. I used the standard cable outlet on the HD box as a source for all the remaining TV sets in the house - with the various splitters in the original configuration to each remaining TV set. They all work as before, provided that the HD box bypass is turned on.

What's the lesson? Use no splitters on the way to your HD set, and connect your remaining TV sets through splitters only after the you HD set has it's full-strength signal. All our TV's are now working as intended. While I did not purchase one, a video signal amplifier (available at electronics distributors) would also likely solve this issue.

I want to say that Shaw Cable certainly lived up to their end of the bargain. They came to install whatever was necessary to make the HD system work for us whenever they said they would come, and got everything operational. Most often, we only hear about problems with regard to missed appointments; I think that a good job also deserves mention.

Derek is in the middle of another "chemo weekend". I think that he may be feeling a little better, because he posted a comment on Facebook a couple of hours ago.

1 comment:

  1. Karl
    I admire your wonderful talent when it comes to all that tech stuff.Now I see where Derek gets it.It fairly makes my old head spin and I think I would dump tv's, printers and the like if I could not use A.G.Bell's invention to call him every time I'm stuck.
    'Bet you're watching the hockey at the moment!