mm wrote:
Today on the news I heard that a big bunch of electronic garage door
openers weren't working in Churchville Maryland because the govt. at
the Aberdeen Proving Grounds was doing something with a satellite or
something. Tomorrow their going to do the same thing around Aberdeen.

People are paying techs to change the freqs, but some may have paid
for other repairs by mistake, one would assume.

Someone in charge admits he didn't get the word out well enough.

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?

2) How could the use of a frequency mess up the garage door openers?
Even if the govt. signal was stronger, why wouldn't the opener still
work? If the govt. signal was picked up by the opener, how come the
doors didn't open or shut. (Apparently they didn't since they would
surely have mentioned that.)


If you are inclined to email me
for some reason, remove NOPSAM :-)


read he
http://www.ddc.dla.mil/news/2005_02_...arage_Door.pdf

"mm" wrote in message
...
Today on the news I heard that a big bunch of electronic garage door
openers weren't working in Churchville Maryland because the govt. at
the Aberdeen Proving Grounds was doing something with a satellite or
something. Tomorrow their going to do the same thing around Aberdeen.

People are paying techs to change the freqs, but some may have paid
for other repairs by mistake, one would assume.

Someone in charge admits he didn't get the word out well enough.

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?

2) How could the use of a frequency mess up the garage door openers?
Even if the govt. signal was stronger, why wouldn't the opener still
work? If the govt. signal was picked up by the opener, how come the
doors didn't open or shut. (Apparently they didn't since they would
surely have mentioned that.)



Front end swamping ?

Garage door openers are coded so that your remote doesn't open every door in
the street ??

Arfa

On Sat, 08 Mar 2008 12:40:08 -0500, mm
wrote:

Today on the news I heard that a big bunch of electronic garage door
openers weren't working in Churchville Maryland because the govt. at
the Aberdeen Proving Grounds was doing something with a satellite or
something. Tomorrow their going to do the same thing around Aberdeen.

People are paying techs to change the freqs, but some may have paid
for other repairs by mistake, one would assume.

Someone in charge admits he didn't get the word out well enough.

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?


No, they don't. Shared and the primary user (military) has priority,
all non-primary users much accept any interference generated by the
primary user.


2) How could the use of a frequency mess up the garage door openers?

Well, if two signals could occupy the same frequency, we'd only need
televisions with one channel, right?


Even if the govt. signal was stronger, why wouldn't the opener still
work?

OK, so your car's FM radio picks up a given station. It picks up the
strongest station, in fact if that strongest station were to suddnly
stop transmitting (say a power or equipment failure) you'd then
probably pick up the next strongest station on the same frequency...
Strongest wins, in this and in fighting.

If the govt. signal was picked up by the opener, how come the
doors didn't open or shut. (Apparently they didn't since they would
surely have mentioned that.)

Huh? So the military signal overpowers the remote... How's it going to
work?




If you are inclined to email me
for some reason, remove NOPSAM :-)

mm wrote:
If the govt. signal was picked up by the opener, how come the
doors didn't open or shut. (Apparently they didn't since they would
surely have mentioned that.)

For the same reason that all garage doors don't open when you push the
remote for one.

--
If only there was a Republican running for President of the United States.

On 03/08/08 12:40 pm mm wrote:

Today on the news I heard that a big bunch of electronic garage door
openers weren't working in Churchville Maryland because the govt. at
the Aberdeen Proving Grounds was doing something with a satellite or
something. Tomorrow their going to do the same thing around Aberdeen.

People are paying techs to change the freqs, but some may have paid
for other repairs by mistake, one would assume.

Someone in charge admits he didn't get the word out well enough.

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?

2) How could the use of a frequency mess up the garage door openers?
Even if the govt. signal was stronger, why wouldn't the opener still
work? If the govt. signal was picked up by the opener, how come the
doors didn't open or shut. (Apparently they didn't since they would
surely have mentioned that.)

Garage door openers (and a bunch of other household electronic devices
(e.g., cordless phones, computers, wireless networking systems, wireless
remote temperature/humidity sensors) are unlicensed devices governed by
Part 15 of the FCC regs. They must not interfere with licensed services
but must put up with any interference from licensed services. So if your
garage door opener interferes with your ham-radio neighbor's
communications, it's your responsibility to fix the problem (e.g., by
replacing or refraining from using the offending device). Similarly, as
long as your ham-radio neighbor is operating within the terms of his/her
license and you keep hearing him/her in your cordless phone, that again
is your problem -- although he/she ought to be willing to assist you in
finding a solution to the problem (but is under no obligation to
actually fix the problem or pay for somebody else to fix the problem).

Perce

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?

As someone else stated the front end of the garage door openers
receiver is being swamped by a strong signal. This signal need not
be the same frequency. It only has to be very strong and dilute the
remote so that it can not be picked up.

In article ,
wrote:

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?

As someone else stated the front end of the garage door openers
receiver is being swamped by a strong signal. This signal need not
be the same frequency. It only has to be very strong and dilute the
remote so that it can not be picked up.

Sorta like what happens when you are trying to use FM channels to
listen in your car to the portable iPod or satellite radio. You get a
strong station even a couple of channels over and you have to retune,
often to the other end of the spectrum.

Today on the news I heard that a big bunch of electronic garage door
openers weren't working in Churchville Maryland because the govt. at
the Aberdeen Proving Grounds was doing something with a satellite or
something. Tomorrow their going to do the same thing around Aberdeen.

People are paying techs to change the freqs, but some may have paid
for other repairs by mistake, one would assume.

Someone in charge admits he didn't get the word out well enough.

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?

2) How could the use of a frequency mess up the garage door openers?
Even if the govt. signal was stronger, why wouldn't the opener still
work? If the govt. signal was picked up by the opener, how come the
doors didn't open or shut. (Apparently they didn't since they would
surely have mentioned that.)


If you are inclined to email me
for some reason, remove NOPSAM :-)

mm wrote:
Today on the news I heard that a big bunch of electronic garage door
openers weren't working in Churchville Maryland because the govt. at
the Aberdeen Proving Grounds was doing something with a satellite or
something. Tomorrow their going to do the same thing around Aberdeen.

People are paying techs to change the freqs, but some may have paid
for other repairs by mistake, one would assume.

Someone in charge admits he didn't get the word out well enough.

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?

2) How could the use of a frequency mess up the garage door openers?
Even if the govt. signal was stronger, why wouldn't the opener still
work? If the govt. signal was picked up by the opener, how come the
doors didn't open or shut. (Apparently they didn't since they would
surely have mentioned that.)


If you are inclined to email me
for some reason, remove NOPSAM :-)
I have used these openers for datatransmission, and the type I used
had 8 tri_state codeswitches.
If the code does not fit, nothing happens, when some outside transmitter
intervenes.
The codestring contained about 42 bytes in total, and it is difficult to
trigger that with some random signal.
In case of interference, you just have to get closer to your receiver,
for it to work.

"Percival P. Cassidy" wrote in message
...
On 03/08/08 12:40 pm mm wrote:

Today on the news I heard that a big bunch of electronic garage door
openers weren't working in Churchville Maryland because the govt. at
the Aberdeen Proving Grounds was doing something with a satellite or
something. Tomorrow their going to do the same thing around Aberdeen.

People are paying techs to change the freqs, but some may have paid
for other repairs by mistake, one would assume. Someone in charge admits
he didn't get the word out well enough.

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?

2) How could the use of a frequency mess up the garage door openers?
Even if the govt. signal was stronger, why wouldn't the opener still
work? If the govt. signal was picked up by the opener, how come the
doors didn't open or shut. (Apparently they didn't since they would
surely have mentioned that.)

Garage door openers (and a bunch of other household electronic devices
(e.g., cordless phones, computers, wireless networking systems, wireless
remote temperature/humidity sensors) are unlicensed devices governed by
Part 15 of the FCC regs. They must not interfere with licensed services
but must put up with any interference from licensed services. So if your
garage door opener interferes with your ham-radio neighbor's
communications, it's your responsibility to fix the problem (e.g., by
replacing or refraining from using the offending device). Similarly, as
long as your ham-radio neighbor is operating within the terms of his/her
license and you keep hearing him/her in your cordless phone, that again is
your problem -- although he/she ought to be willing to assist you in
finding a solution to the problem (but is under no obligation to actually
fix the problem or pay for somebody else to fix the problem).

Perce
This is the same sort of problem that some Chrysler cars had in the 90s. If
you drove by a powerful radar installation, and the beam hit your car, it
would stall due to interference with the electronic ignition/computer
components in the car. The car manufacturer had to come up with a
modification to harden the engine's controls to the radar signal.