[no subject]

Some poor radio astronomer out there probably knows precisely how much
earth-generated RF is floating around and how much it increases each year.
This site:

www.ofcom.org.uk/static/archive/ra/smag/papers/smag02-12.doc

says:

"These tiny communication devices will in many cases be disposable items and
are likely to give rise to a general increase in overall background r.f.
signals"

So it seems to me the RF spectrum is going to get as nasty as home
powerlines have become in the thirty years or so that X-10's been around.

RA's reliability may simply come from the conservative 30 foot radial
distance rating of the RadioRA units.  As RR pointed out, moving transmitter
and receiver closer even slightly results in significantly more transmitter
power reaching the receiver.  Couple that power to the transmission speeds
RA uses, and it's a vast improvement over X-10's PLC abilities.  I'm
assuming RA could try/retry a complex 100+ digit command string at least 100
times before either of us could blink.  (-:

> In this specific case the military frequency was far enough away from
418MHz
> that it was not likely to affect any RadioRA but, in general, their
> "immunity" from interference is more a matter of miniscule market share
than
> technical prowess.

Probably.  But I haven't seen many failure reports at all and they claim to
have 1 million somethings sold (installations, clients, switches,
something - sorry but I can't remember what the million things were but I
was surprised it was that many!)  Still, I wouldn't mind seeing a "shootout"
at a trade show to see exactly how it stacks up against other transceivers
in that band.

> For those who reacted by blaming the garage door makers, a glance at FCC
> frequency allocations shows that nearly the entire spectrum allowed for
> low-power unlicensed use under FCC Part 15 is also allocated for some type
> of licensed use. I doubt there's any easy way to determine what particular
> sub-band might avoid some future problem like this - it goes with the
> territory.

The experience with the door openers also indicates that if the military or
the government owns the frequency (or perhaps just wants to borrow it for a
while), low power users might not be on the "need to inform" list.  (-:  I'd
expect to see more jamming incidents as the military configures itself to
fight against IEDs for the next war, which, if military history is any
indicator, will have nothing to actually *do* with IEDs.  But we will be
ready for it.  Just like we were prepped to fight either a jungle war or a
Baltic war in the 80's but ended up fighting in the desert.  I just wish
Congress could fast-track some troop and vehicle armor the way they do trade
agreements.  )-:

>      http://www.ntia.doc.gov/osmhome/allochrt.pdf
>      http://www.panix.com/clay/scanning/frequencies.html

Lots and lots of gummint bands in dem dere lists!

What I'd really like to know is how Lutron's customer service dealt with the
situation.  What did it cost their NYC customers to switch to channel B?
Were the units field upgradeable?  Even better, could they be upgraded
without being pulled?  With radio modules as cheap as they are these days,
what would it have cost them to design a switch with complete different fall
back frequency, in other words, both A and B in the same switch with either
a DIP or some other way to switch them?  Perhaps even auto-hopping if the
switch can't get through on the primary channel.

--
Bobby G.