Re: garage remote jamming

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Bill Kearney" <wkearney-99@hot-mail-com> wrote in message

<stuff snipped>

> And meanwhile it's nothing but unsubstantiated FUD claiming it's
"possible".
> Shit, ANYTHING is possible.  You want proof it can't be interferred with,
> well, show me one that has suffered from interference.  Otherwise you're
> just spewing "chicken little" style nonsense.  Meanwhile PLC continues to
be
> fraught with perils, often not within it's realm of control, that will
> further hamper it's uptake into the residential market.

While I can in no way vouch for the accuracy of this claim, while looking
for something else (Uniden 5.8 phones)  I did come across this thread:

http://www.avsforum.com/avs-vb/archive/index.php/t-704373.html

and this message:

audiblesolutions    10-07-06, 03:57 PM

[QUOTE=DAP]I do not have any other wireless equipment operating at 5.8 GHz,
but I am sure it is not interferance since the noise does not appear when
using the intercom mode.
[/QUOTE]

<<How have you determined this fact? Just because you have no equipment you
have purchased that uses the 5.8 GHz spectrum does not mean that there are
no other devices also broadcasting at that frequancy that might lead to
issues in your system. I have been on jobs, especially in crowded urban
enviorments, especially high rise aprartment buildings, where all sorts of
external interference caused some system to operate poorly. One famous
example was Lutron's Radio Ra in NYC. It turned out a government agency was
operating on the exact frequancy it was using which caused it not to work
reliablly. They had to bring a spectrum analyzer on to the site to figure
out what was causing the problem. As Newtonian physics still operate and
matter cannot exist in the same space at the same time, how have you
determined that your issues are product related and not enviormental? --
Alan>>

So I cranked up Google to search for "RadioRA NYC problems" and that led to
another document at:

http://www.radiora.biz/technical_info/pdf/RFwhitepaper.pdf.

That described how, in 1999, they added a second frequency to their RadioRA
equipment.  From the description of techniques they examined and discarded,
I'm confident that they are not using any spread spectrum encoding
techniques to transmit their signals.  I'd say we know exactly how they
intend to deal with any interference on their "A" band at 418MHz.  They say:

**********************************************************
RadioRA ?B? Frequency 434 MHz ? one channel (AM)

In nearly a decade?and with over 1 million devices sold?only one isolated
area in North America has interfered with our one channel RadioRA system?New
York City. The ?B? frequency was developed to address this situation.

**********************************************************

That was in 1999, before the WTC and 9/11 and the tests at Elgin, AFB and
Quantico, CA so it's hard to say whether the assumptions they made in that
design whitepaper are still valid.

--
Bobby G.