radar & cars

[panelman]

A strange one......my SO goes to Stansted airport to collect the offspring, when they get back to the car it’s a non starter.

It turns over fine (as far as I can tell listening to it via mobile phone) but refuses to start. Call the recovery lorry, driver says “we get lots of these, it’s the radar, I’ll tow you down the road and it will be fine”

He does and it is!!!! Nothing was touched, he just moved it maybe 2 miles yards and it started.

Car is an 1999 Alfa 145 twin spark which is a paragon of reliability (apart from tonight)

Anyone else ever heard of this?

 

[Comcokid]

The issue is called 'RF Susceptibility'. You should check with your Alfa dealership to see if there are technical bulletins that apply for this issue to your model car.

However, I suspect that the particular location where your car is located has extremely high RF fields, since the tow truck diver had seen it before. The fields may be higher than what the auto manufacturers test for. Industrial vehicles are generally tested for higher RF immunity.

I have heard stories about vehicles driven up the base of some very high power VOA shortwave towers being affected. The people who maintain these transmitters generally have older type diesel engine vehicles which are not affected, and which they use to tow away visiting vehicles. But even with a no-electronics diesel, all the warning lights and buzzers are going off when they reach the base of the tower.

There is also a 'urban legend' about semi truckers, illegal high power CB radios, and sun bugs in the 70's. The last generation VW bug had early fuel injection. Truckers would wait for one to pass, then kick on the transmitter and watch the bug fade back. When the VW would try to pass again, they would repeat the process. They called it "bug mashing". Basically, the fuel injection was susceptible to a strong RF signal.

 

[MikeHalloran]

I guess nobody with a pacemaker goes there.

... at least not twice.



Mike Halloran
Pembroke Pines, FL, USA

 

[swall]

Slightly off topic--I have, occaision, notice static on my AM radio when passing a semi. I assume that the rubber tires act as a static generator under the right conditions. This would be on an interstate highway and I would be passing the truck in the adjacent lane. The static is most noticeable when you pass the duals on the trailer and then again when you pass the duals at the rear of the tractor.

 

[TheBlacksmith]

I had a '81 Olds with AM/FM Stereo. When driving onto Norfolk Naval Sattion, I would sometimes get a strong midrange tone from the rear deck speakers, even with the radio turned off. Watching the ships for a minute, I could determine which ship had their air search radar on, because the tone would be present whilst their antenna was pointed at the car. There is an urban legend (?) that the air search radar at Great Lakes Naval Training Center inadvertantly radiated once, neon signs along the strip outside the base light up, photo flash bulbs in local stores went off and O Hare airport radar was blanked out.

 

[BrianR]

One of the main aspects of my work is EMI/EMC/EMV issues on aircraft and I have seen many instances similar to the ones you describe. Large radar antennas in particular can have some very intense lobes which can be quite nasty over distances of a couple of miles. When the length of something in the field is resonant then the effect is worse. It is certainly possible to light-up fluoro tubes at a distance and I suppose neons and I have seen flashbulbs popping off like firecrackers 400yds away from a powerful ASW radar on an aircraft.

A number of the earlier generation of electronic controlled cars suffered from EMC issues from mobile phones, 2-way radios and radar.

 

[OP800]

Ford has the PATS system that is a reciever to detect the coded keys.
This system has a bus to the processor and the program block containing the vehichle ident info.
If the path is not complete the engine will not be premited to start.
I to had an ocassion the have an alarm for about 30 seconds then it cleared, while driving my truck.
I passed a truck with the driver on his ham radio. I know him and figure that was the cause of the alarm but no real proof.
Never happened again.