XPost: alt.home.repair, sci.electronics.repair
On Wed, 14 Oct 2009 13:14:58 +0100, Ian Jackson
wrote:
>In message , Bob M.
> writes
>>"Jeff Liebermann" wrote in message
>>news:m9bad5l68mh8jh9jbe1cdlufqem3fs6f9c@4ax.com...
>>
>>>
>>> It's not just weather stations. It's any kind or thermometer that
>>> uses wireless for communications. Most of them are on 433.925Mhz.
>>> Also remotes for air conditioners, room lighting, door locks, vehicle
>>> alarms, vehicle keys, SCADA systems, and mess of other gadgets that
>>> involve key fobs and very low speed/thruput wireless data. Just enter
>>> "433.925" into a Google search for some hints.
>>
>>Also add "ham radio" to that list. 420-450 mHz is a popular ham radio band.
>>
>>The same 420-450 mHz band is where the US Air Force's "Pave PAWS"
>>radars operate; they have a range of over 3,000 miles. Located at Otis
>>AFB, MA, Beale AFB, CA and Clear AFS, AK, these radar beams extend out
>>over the ocean, primarily.
>>
>>And, does the OP's house have metal siding? Metal siding greatly
>>reduces the penetration of the transmitter signal to the inside the
>>house. I had steel siding at the old place & this one; the old place
>>had wireless doorbells that didn't always work, even with new
>>batteries. This place has wired doorbells that always work.
>>
>>The OP's remedy is to install wired doorbells.
>
>Don't forget that these wireless devices are "made to a price". They
>usually employ the minimum amount of circuitry which enables them to
>function. They may respond to an RF signal on almost ANY frequency,
>provided it is strong enough. It doesn't have to have the correct coding
>etc.
>
>Of course, 'electronic' wired devices (even those where no 'frequency'
>is involved) also can also suffer from RF interference. But a purely
>'electrical' device - like a doorbell - should be OK.
Years back a cop cruiser keying his mic out front could make many
garage door openers operate.
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
|
