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[file28]

hi there was wondering if this has happened to anyone else
when visiting the wife in hospital tonight parked in open air car park roughly in same area as usual.guy parks next to me with a focus st thingy he gets out hits the fob button nothing happened, i get out of my mig to ask if he left a window open or similar he checks everything and tries again no luck , in the meantime i try to lock mine with the fob no go
we both try with the keys no problems then with the fobs still no good so he moves his car about 50 yards tries again this time ok
i leave mine where it is still no fob working
when i get home fob working ok no probs
on looking around the area it seems like a few other people were having probs with their remote locking systems also  their area is well covered with cctv and was wondering if the radio signals affect the remote locking systems
when taxi-ing many years ago used to notice a lot of static on the two radios in the cab at fillings or when driving around heavily cctv-ed areas

[HolyCount]

Hmmm -- down the road from where I work is a Nationwide Auto Centre -- the manager there keeps going on about the cars in the yard -- every now and then the fobs and some of the electrics go scatty for a while -- on all the cars at the same time -- he reckons it's a nearby Mobile phone mast !  But thinking about it -- the car park opposite has several CCTV cameras !!!

[Entwood]

A lot of CCTV cameras have built-in or attached IR "lights" to enable them to work in "low light" conditions - when they switch to IR mode - It is not unknown for this mode to be left active during the day- the IR sweep can cause major problems for cars with IR Fobs

[file28]

twilight zone comes to mind ot the mo
a govt conspiricy theory?

[HolyCount]

Those IR lights are very useful for showing up accident damage -- many moons ago I was the proud owner of a Truimph 2000 -- looked great in burgundy --- saw it one evening on an IR CCTV set up and every panel was a different shade !!!!!!

[master-sambo]

I used to work near a police station, and their transmitter caused chaos with some remote fobs.  I had a guy with a brand new E class couldn't open the car with the fob and couldn't start it because of the transmitter.

The RAC moved his car a few yards down the road and voila! It worked.  It happened to a couple of other vehicles too.

[Kevin Wood]

Many public buildings have their roof space pimped out to various radio operators for base stations, if they don't use mobile radio themselves.

The radio fobs (not IR) are in a band that is used by numerous "licence exempt" devices and is actually part of one of the UK amateur radio bands, so someone could be sitting in the car park chinwagging on the radio and you'd not have a prayer of getting into your car.

I notice mine is less reliable in the multi storey in town where there are a couple of base stations on the roof.

This is compounded by the fact that the recievers in the car are built to a price and don't have very good selectivity.

Kevin

[Dave DND]

This is compounded by the fact that the recievers in the car are built to a price and don't have very good selectivity

That is so true  

[Marks DTM Calib]

This is compounded by the fact that the recievers in the car are built to a price and don't have very good selectivity.

But still a million times better than those of 20 years ago....

As for interference from phone masts etc, VERY unlikely....if they were emitting such a broad spectrum you would be loosing a lot more than just the RF operation.

I suspect its more likely to be some other gadget or wireless security setup which all tend to use the LE frequencies.

[Dave DND]

Its often the harmonics that cause the problems from phone masts, but biggest culprits are two way PMR radios, used by Taxis, and emergency services.

IR dispersion from CCTV as per original thoughts is also correct - we have had fun with that one in the car park by turning on the night cameras when problem customers return to their cars - when they come back into the shop with their tail between their legs asking for help after a shouting match, its quite comforting

 

 

[waspy]

When i was a CBer many years back, alot of my mates used to go up to Allport Stone which a local beauty spot, but the police have a big mast up there too. They banned all Cb radio use up there, because the CBer's would interfere with the emergency services.
We used to here alot about tv pictures getting interference too.
When my nieghbour starts his bike up, that interferes with my digital tv.
So my opinion is yes, when the equipment is close enough, even though the bands are far enough apart they can cause havok.

[Kevin Wood]

Its often the harmonics that cause the problems from phone masts, but biggest culprits are two way PMR radios, used by Taxis, and emergency services.

Transmitters are generally pretty clean - a 200W mobile phone BTS will not have a spurious that's anywhere near to drowning a 10mW car remote, and they're up at 900 / 1800 MHZ anyway, with tuned antennae that further attenuate spurious emissions.

Whether the receiver is desensitised in the presence of a strong signal-even this far out of its' passband is another matter.

I suspect the main cuplrit is PMR and particularly Tetra systems that are starting to creep up to that part of the spectrum, especially as RF remotes are generally basic AM transmitters that are badly affected by the bursty TDMA structure of a Tetra transmission.

Even then- as in 99% of interference, IME, it's the receiver or its' installation to blame, despite the perception that it's the transmitter that's doing the interfering. Ask any frustrated radio amateur! receivers are designed to work acceptably in typical conditions so if you happen to be next to a base station, a police station, a radio amateur, CB'er, etc. All bets are off. They won't have spent the money to guarantee that your receiver is good enough.

They have got better because that goal has moved. There are more wireless devices around than there used to be so the performance required has increased. There still are, and always will be, scenarios in life that will challenge them.

Thank goodness the Omega has a cylinder lock too.

Kevin

[zirk]

Theres probally an AirWave Site on the Hospital, The UK Goverment Tetra National Radio System, the Frequency's are low UHF 380Mhz to 420Mhz, seem to recall that most Fobs work in 418 Mhz.

Used to be run by BT, now O2, they use most Police, Fire and Ambulance Stations as fill in Base Sites to support their main Mast Network.

[MikeDundee]

I get the same problem, had it yesterday and again today, usually in Asda car park, today at Surrey Quays (parked right next too CCTV pole)

[tmx]

its IF Radiation i used to work at a satellite station and if you parked under a big dish the car alarm would always go off and your mobile wouldnt work i would assume that a IR CCTV camera probs uses the same signalls

best way to check for interfearence is to listen on long wave radio you can hear all sorts of interference wireless lans cctv mobile masts all sorts

bt just had the mtce contract for tetra i believe its really an o2 product i thought it worked on o2s gsm 900mhz range but used a CUG Closed user group ie police ambulance fire etc  all have different sideband frequencies