Can I hijack a TV channel in my house?

Question

Is there a way to hijack a TV channel to display a certain feed instead of a blank channel on my TV? What I mean is, let's say channel 28 isn't used. Could I tap into that. How do hotels do it with their special hotel channel?

Answer 1

Here's how the cable systems do it (I used to build these things for the cable company):

When the signal comes in it is split in two directions. One side goes to the input of a cable converter and the other goes to a very narrow channel filter - called a notch filter - that has been tuned to only filter out one channel (say, channel 3). The cable box is used to select a cable channel (say, HBO) and its output is on channel 3. Then the output of the filter and the cable box are combined by going backwards through a splitter - such that it now functions as a combiner. Now the spectrum of channels has channel 3 assigned to play HBO. We then ran this to an amplifier that was used to feed all the rooms in the hotel.

If you want to put the channel from the cable box onto some other place in the spectrum (say, channel 10), you have to use a TV demodulator/modulator that demodulates the TV signal from the channel 3 carrier and modulates it onto a channel 10 output channel. Also, the notch filter must now be tuned for channel 10.

Answer 2

Paul's answer is correct if not costly.

Cheapest way to do it is use either a VCR with Video and Audio inputs and a channel 3 or 4 output <<< OR >>> an RF modulator to generate the signal. Connect your video and audio source to the VCR or the modulator. Connect your TV cable feed to the input of either and when the VCR or modulator is on you have hijacked channel 3 or 4. Amplify this if you want to send it to more than one TV with an antenna amplfier and splitter. Bypass it with A/B RF switches if you want to set it only on some TV sets.