Re: Frustration with X10 Powermid

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

<km@xxxxxxxxxxxxxxxx> wrote in message
news:1144384120.977311.30730@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> I have done some new experiments.
>
> I decided to take the Powermid transmitter outside my apartment, and
> found that the LED glowed even brighter outside. I then drove it a few
> miles in each direction and got the same results consistantly. In my
> car I used an AC inverter to power it, but I also just plugged it into
> AC at various outdoor power sockets. The results were very consistant.

I wouldn't expect the Powermids to work in bright sunlight.  All of mine are
located away from both sunlight, CFL light and known EMI generators such as
TV sets.

I would suggest putting one inside of a metal box or can to block out as
much RF as possible just to test to make sure you  don't have a defective
unit and to see whether your area is saturated with EMI that affects the
unit.  As someone else noted, you may be located near a ham radio station or
some other source of interference.  Based on the experiments you've run,
that seems to be very likely.

> I took it over to a nearby office building and tried it at various
> points in the building. In the interior the LED was dark, but at points
> near the exterior or near windows it glowed.

As I said, I've taken great pains to shield my units from direct and even
strong indirect sunlight.  They just can't handle it.

> In my aprartment there is no spot where the LED stays dark. It's a
> brick building constructed in the 1950's, which I presume has walls
> that provide less shielding  than the  the new office building.

It's hard to say.

> I don't know if there is something special in my area transmitting at
> 418mhz, or if this is typical. My guess is that it's not that unusual,
> and that most people have better shielding. Even in my apartment the
> background LED glow does not cripple operation with most of my IR
> devices. I started into this because just  one of my IR controlled
> devices would not work either through the Powermid, or even directly
> when the Powermid transmitter was on. Most of the others work but are
> intermittent at times.

The fact that the device doesn't work directly with the Powermid on is bad -
it certainly was the problem that made me put each Powermid on a separate
appliance module so that I could turn on only the one I needed and could
leave the others turned off.  IME, it seemed that the problems multiplied
when all the Powermids were transmitting, even though only one of them was
actually sending commands.  I also have to keep them ALL turned off when I
am controlling devices locally in the AV room.  That means that mine are
receiving and repeating junk that interferes with the real IR signals.

> Probably an unlucky device, poor shielding in the walls, and an unknown
> RF source painting the neighborhood.

It would be nice to figure out which!

> I have tried a Terk a year back which operates at 433mhz and it was
> similarly balky. It was a short test, and at the time I didn't test for
> background glow outdoors. Either that background is over the whole
> 418-433 range, or these devices are not real discriminating by
> frequency.

Do you have an X-10 RF gear?  Is it similarly balky?  I found that when I
had a continuously transmitting Palmpad it knocked out the Powermid closest
to it, but left the others operating as normal.

> I was going to try a URC-9910, but I see its also at 433 which is
> discouraging. (Also they seem to be in very short supply).

I think Mr. Gardener's advice is probably the best solution for you - go
hardwired.   I would expect that solution to be far less troublesome but
there's a remote chance that whatever's plaguing your Powermids could also
bother hardwired IR sensors.  If you buy hardwired gear, buy from someone
who'll accept returns just to be sure.

--
Bobby G.