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Re: Transmitting an all is well packet from sensor to main control unit



JoeRaisin Wrote:

>I've always enabled it.

Don't need to.  In fact, it can cause more trouble than it could
prevent.


>This guy should be coming at the problem from the other direction.
>What, exactly, is done when a signal (any signal) is being jammed?  How
>do you stop a radio wave in mid air?

The RF Jam doesn't "stop" a radio wave, the panel tells you a matching
~345Mhz transmission has been active for at least 20s.  That is possible
due to a malfunctioning x-mitter from *any* source, a military aircraft
in the area for example.

I remember a story a couple of years back when some kid in his 20's
bought a new flat-screen TV.  Everything was fine for 2 days until the
whole area's police, fire, and medical showed up in full force to the
poor slob's door.  The TV had a leaky signal, matched perfectly to the
406 MHz satellite personal locator beacon; the service run by these
folks:
http://en.wikipedia.org/wiki/Cospas-Sarsat



-------------------------------------------

VISTA-20P: Programmable - *22

DETAILS: Optional RF jam detection for wireless systems detects a
condition that may impede proper RF reception (i.e., jamming or other RF
interference);

1 >causes keypad display, and
2 >sends a report to central monitoring station(if trouble reporting is
enabled). (Check 90 / RCVR jam.)

Perceived RF "jamming" occurs when something in the operating frequency
range (345.xxxMHz) has been transmitting for 20 seconds or longer.
Things like microprocessors,  (like the one in the alarm panel) and even
microwave ovens need to be 10' away from the receiver.

Honeywell was wise to use 345MHz as opposed to the higher freqs. for the
5800x series equipment because the Govmt. is going to take over the
entire 800MHz spectrum.  I reckon DSC saw that coming, or were they @
900-920MHz already?


345MHz is in a protected spectrum, and come on...  somebody would have
to build a high power jammer on an unauthorized freq. just for a smash &
grab?   Even that doesn't really help much.  They are not going to
dispatch on a supervisory signal.  And if the intruder gets inside, just
have some hard-wired motions on standby so wireless detection is not an
issue.  Plus, aren't you more likely to hard-wire doors anyway?  The
bad-guy has to exit somehow after he rapes you and kills your dog!

The Rx does not automatically lose communication with the Tx when
another signal is present.  You may have one problem transmitter that
misses a 20 second 'jam session' on a semi-rare but innocuous
occurrence.  I guranfuckintee that will happen on a Sunday night just
when you're done eating, showered, ready to smoke a bowl and watch
"Family Guy".  Not so funny now, huh?  ;-))

---------------------------------

Below is what is the thing to worry about working 100%, instead of .007
coming in with a jamming device.

----RF RCVR SUPERVISION CHECK-IN----

DETAILS: The panel supervises the receiver continuously. If connection
is lost, check 100 will show on the keypad within 3 minutes. If there
are supervised transmitters programmed into the panel, the receiver must
hear from at least 1 transmitter in a 12 hour period. Failure to hear
from any will also cause a check 100. The panel will go into Alarm 100
if armed at that time. A supervisory caused by a failed check in will
not cause an alarm and will not prevent the panel from arming from a
scheduled arming.

>Federal Allocation  Non-Federal Allocation  Federal Usage
>335.4-399.9 MHz
>FIXED
>MOBILE

>G27  G100
>335.4-399.9 MHz  This band is a critical military radio communications band that has been preserved for military operations by the
>North Atlantic Treaty Organization (NATO); and within the individual NATO member countries.  The military
>nature of this band has also been maintained by certain allied and friendly nations outside the NATO alliance
>such as Australia, Israel, New Zealand, and Saudi Arabia; and by the European Cooperation Partner nations and
>the Partners for Peace nations.  It is vital to military and Coast Guard operations due to its excellent propagation
>characteristics
>The military agencies and the Coast Guard use this band for air-to-ground and air-to-air radio communication
>systems for the control of military aircraft, including unmanned aircraft.  The military agencies and National
>Aeronautics and Space Administration (NASA) use this band for airborne communications networks via
>multichannel radio relay systems. Air-to-air and air-to-ground modes are used.
>
>The military agencies use this band for a major tactical radio communications system providing anti-jam,
>secure, frequency-hopping radio communications system.  The system is used for tactical air-to-air, air-to-
>ground, and ground-to-air communications, including interoperability communications among Air Force, Navy,
>Army, and NATO units.  Over 60,000 radios have been manufactured for this system.
>
>The Federal Aviation Administration uses this band for aeronautical communication systems for the air traffic
>control of military aircraft.
>
>The Coast Guard uses this band for tactical operations such as ship-to-air and ship-to-ship clear and secure
>voice communications.  The Coast Guard also uses this band for data link communications.
>
>NASA uses this band for voice communication related to Space Shuttle operations and air-ground-air
>communication for flight research.
>
>The military agencies use selected portions of the 380-399.9 MHz band for trunked land mobile radio
>communications networks, primarily for non-tactical applications such as military base security.
--

"We completely understand that he's not able to come, but that the invitation was made in that spirit,"
--White House Press Secretary Jay Carney, on Obama inviting Bush to the World Trade Center site.


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