Infrared remote extender -- random turn on.

Has anyone experienced this? It doesn't make sense because remotes need spe cific data pulse to work.

Anyway, have a Denon receiver that I recently added a Terk remote extender to, you know the RF link xmtr/rcvr pair type? Never had this problem until I used the extender with it and also, have the same model extender in anoth er location with never a problem.

That problem being, the receiver will randomly turn on by itself from time to time. !

I understand that line noise could affect these receivers but still, a turn on command would require specific logic in order to turn on the receiver s o I don't get it. (at all). ?

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pecific data pulse to work.

r to, you know the RF link xmtr/rcvr pair type? Never had this problem unti l I used the extender with it and also, have the same model extender in ano ther location with never a problem.

e to time. !

rn on command would require specific logic in order to turn on the receiver so I don't get it. (at all). ?

No idea... can you point it at a photodiode, put it on a 'scope and make su re all the pulse patterns look the same. Or maybe you'll see something else?

George H.

Reply to
George Herold

Some years ago I used the X10 IR remote extender system (the "black pyramid" type) for a while. I came to agree with a statement I'd read... "Those things are evil." The Terk may have the same issues.

The problem is this: the IR/RF/IR repeaters tend to operating in a "noisy" part of the RF band, and they have RF receivers with extremely poor selectivity. The X-10 models (at least) seem to use a fairly simple "Oh, I sense RF carrier, turn on the IR emitter LED" design. These allow the repeater to carry the IR pulses from a wide range of IR remote controls, and reproduce the widths of the on/off pulse patterns fairly well, without actually having to "understand" the IR protocols being used.

The down side is that due to their poor RF selectivity, they are

*very* prone to pick up RF interference and turn it into pulses of IR. Similarly, the IR-to-RF pickup will gladly "repeat" pulses of IR such as may come from a compact fluorescent lamp, which the RF-to-IR receiver unit will then reproduce.

To make matters even nastier, if you put the RF-to-IR receiver for one of these near any sort of digital electronics (and that includes almost all set-top boxes, DVRs, digital TVs, etc.), it can quite easily pick up low-level RF noise from the digital circuitry ("switching birdies") and turn it into IR pulses.

What this all adds up to, is that the RF-to-IR retransmitter is likely to be very prone to "nonsense chattering". In some installations, it can be *constantly* emitting nonsense bursts of IR pulses.

Sooner or later, it can emit a pulse train which your Denon receiver (mis)understands as a "power on" code, and *BING*. It's on. The longer and more complex IR coding the Denon uses, the less likely this is to happen... but some devices use a pretty simple code, and the chances of hitting it by random accident are higher than you might think.

I added a monitor LED to the emitter setup on my X10 repeater, and I could see that it was happily babbling away due to RF noise any time I located it within a few feet of the stereo cabinet... and did so sporadically even when placed across the room.

Then, add to that the possibility that one of your neighbors has a similar IR/RF repeater, and happens to have a Denon component or one which uses the Denon remote control coding. They could be turning your receiver from next door, without knowing it.

If you need to use an IR repeater, consider changing to one which uses a wired-in connection (over coax, CAT-5, phone wire, twisted pair, or etc.) rather than RF. It will be much less unreliable.

Reply to
Dave Platt

Yeah, I knew these were constantly receiving garbage but I always said to m yself even if it's a simple 1 byte code then it would be pretty weird for i t to see something valid. But I hear ya, and glad to see someone knows what I'm talking about. You still say to yourself though, what are the odds it gets a valid turn on code (!) I do have the Terk rcvr in a pretty noisy env ironment so I'll try moving it.

thanks for the feedback.

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rf interference from something 'wireless' in the area?

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David Eather

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