Re: Help : RF Keyfob blocked on Driveway

["rb_ziggy" <rb.lists@xxxxxxxxxxxx>]

A friend of mine had a wireless video extender (the type of thing that
sends video from one room to another).  This interfered with rf car
openers around 40 to 50 feet away.  Seemed to be particularly bad with
BMWs (both mine and his).  Even standing close to the car did no good
in this case.

So its entirely possible that the wireless cctv is doing similar or
someone is using a similar device somewhere.

It was really annoying. I seem to remember that chucking the device in
the bin did the trick.


--- In ukha_d@xxxxxxx, "seniorsimon" <simon.ryley@...>
wrote:
>
> Can you tell us the brands and models of the cars? It might help to
> narrow down the problem.
>
> I can also confirm that wireless doorbells are a known issue for
> interference with vehicle RF remotes.
>
> Will the remote work if you hold it right next to the car?  Common
> places for car RF receivers are above interior mirror mount, in the
> centre of the base of the windscreen, (under the top of the dash)  by
> the radio/GPS aerial at the rear of the roof if the car has one, or
> under the rear parcel shelf if its a saloon.  Try holding the
> transmitter close to those points to see if it will open.
>
> Finally, will the cars start if you open them with the key?
>
> Simon
>
> --- In ukha_d@xxxxxxx, "Ian Davidson" <ian@> wrote:
> >
> > Hi
> >
> > Most keyfobs operate on 433Mhz (I think 433.920 off hand). This
is a
> > heavily used channel for many things. Has as been mention
wireless
> > doorbell and also temperature sensors, outside lights with
internal
> > buzzer etc etc. Any of these items crashing causing the
transmitter to
> > stay on permanently will cause the issue. Another cause is NOT
mobile
> > phone masts but masts with UHF transmitters on them, these can be
the
> > new police tetra masts but also older commercial UHF systems. The
final
> > cause can be a local radio amateur using the 70cm band. The last
two
> > causes are due to the cheap receivers built into the cars, not
only do
> > they receive there own channel but get de-sensed when a very much
> > stronger signal is being transmitted on a nearby channel. I think
a
> > keyfob is a 10mW device whereby our commercial UHF systems can
run 25W
> > erp a few Mhz away.
> >
> > A cheap radio scanner that covers UHF would allow you to find
most
> > items. Although the devices are digital they still make a noise
on the
> > scanner and enable you to track it to some degree. In really bad
cases
> > OFCOM may help although they do not have to as it is an
unlicensed
band.
> >
> > Regards
> >
> > Ian D.
> >
> >
> >
> > -----Original Message-----
> > From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
> > Of noughtomate
> > Sent: 26 October 2006 15:31
> > To: Ian
> > Subject: [ukha_d] Help : RF Keyfob blocked on Driveway
> >
> > Hi,
> >
> > Hoping you guys might know a thing or two to help me.
> >
> > Me and the Mrs. Cars are parked on our drive way.
> >
> > Once/ Twice a month we find that are key fobs to our cars are
rendered
> > useless. The cars do not respond to open or close using the RF
keyfob.
> >
> > I've eliminated battery and car/fob sync issues and it's abit too
co-
> > incidental it happends to both of our cars at the same time.
> >
> > I've spoken to the neighbours about the problem, but they've not
> > experienced any issues.
> >
> > If I park the car on the road, a house or two away, the cars
respond
> > fine to the keyfob.
> >
> > I'm convinced there's some kind of RF blocker / interrference in
close
> > vicinity to the house but I really can't think of what it is.
> >
> > The only bits of outdoor kit I've recently installed in the past
year-
> > and-a-half since I've lived there are a Comfort Alarm system
(Alarm
> > bell faces drive) and a hard-wired CCTV camera which is hardly
ever
> > on. The Alarm Bell has a luminosity detector which I use to
automate
> > my lighting.
> >
> > I know my neighbour has wireless CCTV - I can pick up his signal.
That
> > aside, I've got the 'usual' RF devices - Harmony 895 (RF switched
> > off), baby monitor, Bluetooth keyboard and DECT phone.
> >
> > But I'm not convinced that these could be causing RF
interference.
> >
> > Could anybody advise on how I could narrow down / fix the problem
?
> >
> > Do keyfobs work at a particulr frequency range, which could clash
with
> > appliances ?
> >
> > I tried a Maplin RF Detector (http://tinyurl.com/y4x69c) , but it
> > didn't detect anything.
> >
> > Any help would be much appreciated.
> >
> > Many Thanks,
> >
> > Balraj
> >
> >
> >
> >
> >
> >
> >
> >
> >
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> >
>





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