Can I Lengthen wire of IR emitter?

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don87109
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Can I Lengthen wire of IR emitter?

Post by don87109 » Wed Jan 06, 2010 7:33 am

I have a Replay TV (like Tivo) that has an IR emitter meant to stick on to a cable box for changing channels, etc. I want to lengthen the IR current 6' wire to about 60 feet to connect to a cable box in another room. Does anyone think that will work, I have some cat 5 lan wire that I could use.

I suppose I could buy a product like X10's IR extender, but I suspect that these can be troublesome and hardwiring sounds more reliable if it works.

Thanks for any feedback, suggestions, etc.

P.S. I have seen the Mark 5 and other circuits that I could probably build, but if I can simply extend the wire why not do that?

don87109
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Re: Can I Lengthen wire of IR emitter?

Post by don87109 » Wed Jan 06, 2010 12:22 pm

I decided it was easy enough to give this a try and it worked perfectly!

Now I'm thinking why bother running a new wire, why can't I share the RG 6 coax bringing the TV signal from the remote cable box? I suspect that the frequency of the IR signal and the TV signal are very far apart (50MHz vs 30-200 kHz) so separating them should be easy.

I am planning to have splitters on both end of the coax anyway and the splitters don't have any DC continuity (and I'm guessing that the impedance at IR signal frequencies is also very high). So If I connected the IR emitter signal to the trunk portion of the coax (between the splitters), the high impedance of the splitters will probably keep the IR signal from getting into the TV/cable boxes. The remaining problem would be how to keep the TV signal from getting into the IR circuit, possibly loading down the TV signal. I imagine an appropriate choke would solve that problem but I have no idea what value I need.

I'm pretty weak on RF circuitry so this might be a totally wacky idea.

Any thoughts?

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haklesup
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Re: Can I Lengthen wire of IR emitter?

Post by haklesup » Wed Jan 06, 2010 12:54 pm

I think the cable signal is less than 1V p-p AC waveform while the IR is a pulsed DC of somewhat higher voltage. You will need a diode to block the DC signal from adding to the AC cable signal. I've seen some diode traps used to power a cable amplifier with the same coax as the signal so I know its possible with DC but not sure if the pulsed DC will cause additional problems.

don87109
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Re: Can I Lengthen wire of IR emitter?

Post by don87109 » Wed Jan 06, 2010 5:52 pm

Thanks, haklesup, I'll keep that in mind.

Right now I'm leaning toward simply pulling a new cable, but if I hit any difficulty maybe I'll pursue sharing the RG 6.

Don

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CeaSaR
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Re: Can I Lengthen wire of IR emitter?

Post by CeaSaR » Wed Jan 06, 2010 7:17 pm

Keep in mind that Cable Co's don't take kindly to any messing of their signals by us mere mortals. Check
your Terms Of Service Agreement to make sure you don't violate anything in any way.

CeaSaR
Hey, what do I know?

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