From: NONONOmisc07@fmguy.com   
      
   In sci.electronics.repair, on Sat, 17 Sep 2022 11:45:10 -0700,   
   dplatt@coop.radagast.org (Dave Platt) wrote:   
      
   >In article <3806e8b2-213e-4c3d-80bf-979f608c1b1en@googlegroups.com>,   
   >ohg...@gmail.com  wrote:   
   >   
   >>There is a *tiny* window where a digital signal is usable and when it   
   isn't.  If the powermid is flashing, it does mean it detected an IR signal   
   >>yes, and it certainly can also mean the signal is gibberish from the remote,   
   but I can tell you in over 50 years in consumer electronics, I can't   
      
   50 years is a long time.   I've been watching tv for 50+ years but I   
   don't think that counts as much.  And some of that time the remote used   
   tuning "forks" instead of IR.   
      
   >>recall seeing more than one or two remotes that put out an IR pulsed signal   
   that also put out gibberish or the incorrect code at the same time.   
   >>IOW, if they transmitted IR, they were generally good.  Could the powermid   
   being seeing a signal too weak to reliably get the code read?  I guess,   
   >>it depends on what the light  means.  It could mean signal detection or it   
   could mean code readable.   
   >>   
   >>What if you take your remote directly to your  DVDR?   
      
   Excellent idea.  It's upstairs and sometime the food will get cold, but   
   still, I will do that next time.    (Unless I forget, which will   
   probably happen the first couple times.  IOW it will take a while to get   
   back to you all.)   
      
   > If it responds immediately, the DVDR and the hand unit are good and the   
   powermid is bad.  If   
   >>the DVDR doesn't respond immediately, the powermid is good and the hand unit   
   or DVDR is bad.   
   >   
   >Those IR -> RF -> IR PowerMod relay devices are... well, rather evil, IMO.   
   >   
   >The design has a couple of limitations / vulnerabilities:   
   >   
   >(1) The IR receiver isn't very selective - it response to   
   >    pulsed/modulated IR having a broad range of modulating   
   >    frequencies.  This is necessary in order to allow the device to   
   >    work with a broad range of IR remotes, but it means that the IR   
   >    receiver can be "swamped" by IR noise from other devices.  In   
   >    particular, some compact-fluorescent and LED lights seem to put   
      
   Well, I do have a lamp with an LED bulb in it in the kitchen where all   
   this tv stuff occurs.   And sometimes it's on and sometimes it 's off,   
   so I will pay attention, and turn it off when there is a problem.   
      
   >    out a bunch of modulated IR, and this can interfere with the   
   >    detection of IR from a remote control.  Worse, it can cause   
   >    the IR receiver to start sending gibberish "remote control"   
   >    signals via RF.   
   >   
   >(2) The RF receiver at the far end isn't very selective, either.   
   >    As I recall it's tuned to a frequency in the 433 MHz ISM band,   
   >    and the band-pass is pretty wide.  As a result, RF noise in   
   >    this band (even "hash" from computers, etc.) can cause the   
   >    receiver to "think" it's seeing input from the IR module,   
   >    and it will start spewing out meaningless IR pulses from   
   >    its IR-transmitter dongles.   
      
   There's nothing much in the bedroom... wait.  The ceiling fixture has   
   compact fluiorescents, and while they shouldn't be on when I'm   
   downstairs, maybe sometimes thay are.   
      
   >The combination of these two design weaknesses means that a PowerMid   
   >setup has a tendency to spew meaningless IR pulses into the   
   >A/V components at the receiving end.  This can prevent proper   
   >repeating of IR from a remote control in another room, and it can   
   >also interfere with the proper detection of commands from an   
   >IR remote in the main viewing room.   
      
   It's good to know about these problems, so I won't change the batteries   
   when t hey are not the problem.  The remote is wrapped up in plastic to   
   keep it clean when I'm eating, so that's even a bigger r eason, plus I   
   don't want to waste batteries.   If it's the powermid, that's not great   
   but I can live with it.   
      
   At first I used to use, it might have been called Cricket.  It had ssome   
   little green animal as the logo and the transmitter was much smaller.   
   It clipped on the end of the remote, and the receiver could go in the   
   other end of the bedroom and shine all across the room.  That worked   
   well for a few years.  I forget the eventual problem was.   
      
   For the powermid receiver I bought a wire with 3 beads at the end, but I   
   only use one, for the DVDR.    I still have things to play on the VCR,   
   maybe eventually.   
      
   >Observe the PowerMid repeater "pyramid" for a while, when you   
   >know that nobody's using the system.  If you see the "activity"   
   >light flicker, you have interference problems.   
      
   Okay   
      
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