RFI in an Isuzu

The caller’s car dies when she passes this radar dome (FAA):


Last pic shows the fire station.

She should contact Isuzu dealer to see if there is a fix - probably only needs a choke on computer power wire.

I agree with DevoutHeretic. See if the dealer has an answer.

Most likely the cars wiring is acting as a antenna, and is presenting the radio signal to the car’s computer, which gets confused and turns off the car.
Shielding the car with aluminum foil is a good start, and fits well with the area 51 theme.
As part 2 of the science experiment the caller can try putting some “snap together ferrite choke cores” onto the wires leading to the computer; if the wires are easily accessible. These cores can be found on old computer monitor cables or at Radio Shack Catalog #: 273-104.
Good luck with the science fair poster.

(The cheapest solution is not driving close to any radar domes. :slight_smile:


Dear Knuckleheads:
I am concerned about the lighthearted advice you dispensed during your 5 November 2011 broadcast to the caller from Keller, Texas, whose problem was her car stalling when driving near a ‘weather ball’ (i.e., an FAA radar dome) on a local road.
In order to shield its computer from electromagnetic (EM) radiation which you suspected as the cause, you humourously suggested that she wrap parts of her car in tinfoil.
As anyone who has ever mistakenly placed a tinfoil-covered dish in a microwave oven (i.e., a ‘radar’ range) can attest, the presence of a conductor within an EM field of sufficient strength quickly generates some pretty impressive lightning-like sparks.
I shudder to think what might happen to this poor woman (and her tank full of, y’know, gasoline …) in these potentially disastrous circumstances. It’s a good thing that weather dome is located next to a fire station.
Seriously – while it’s entirely possible that, by design or defect, her car’s electronics are insufficiently shielded from EM, it’s also likely that the dome’s emitters aren’t properly calibrated, and they are putting out a much hotter signal than is necessary. After all, the FAA operators aren’t going to worry about a signal with too MUCH reach; they want all the range they can get, to gather them most weather data possible. But if it poses a potential threat to passing motorists (not to mention any birds flying in the vicinity) it’s a problem that needs to be addressed.
I suggest that you contact your caller and advise her to forget the tinfoil science experiment, and choose a different route, at least. And if that dome thing actually IS a CIA / NSA / Who Knows What Agency listening station, don’t worry, they’ve already heard from you (and me).
Best Wishes and Happy Motoring!

“She should contact Isuzu dealer to see if there is a fix”…
“I agree with DevoutHeretic. See if the dealer has an answer.”

Ummm…have you guys noticed that there have not been any Isuzu automobile dealers in the US for several years? The Trooper has not been sold in the US since 2002, and the Rodeo ceased to be sold in the US in 2004. There have been no Isuzu passenger vehicles of any type sold in the US since 2008, at which time the dealerships ceased to exist.

Yes, there are still a few dealerships that sell Isuzu commercial trucks, but do they have any special expertise regarding the orphaned Isuzu passenger vehicles? Somehow, I doubt it.

Tom and Ray,
You recklessly perpetuated the myth that radio radiation is harmful. It almost never is. The harmful stuff is ionizing radiation, principally x-rays and gamma rays. Ionizing radiation is emitted by dental x-ray machines, computerized tomography (CT) machines, and by nuclear reactors and waste. It can cause cancer in sufficient doses, although a modest number of medical x-ray procedures is OK. Radar uses radio waves with a photon energy far too small to affect chemical bonds in the body. X-rays and gamma rays, on the other hand, can and do break chemical bonds and cause damage in our bodies. Properly administered, they do have good medical uses.

That said, one should stay away from a microwave oven with a leaky door or a broken interlock that allows it to operate with the door open. It could ruin your vision. The radar dome is unlikely to have enough power at the car to cause sparks, and very unlikely to be powerful enough (outside the fence) to harm people.

Your caller’s giant golf ball contains a radar; it’s known as a Radome, or sometimes popularly as a Weatherdome. The FAA sign means it’s part of what’s popularly known as Air Traffic Control, specifically the Terminal Radar Approach Control (TRACON) part. It’s probably near an airport approach path (although it may be several miles from the airport so that isn’t real obvious). The spherical shape is strong, so it can be built with lighter materials transparent to radar. Some radomes may have hidden who-knows-what during the Cold War, which may explain their nefarious reputation. Nowadays all of them really are innocuous.

Radiation from the radar to passing cars is quite small because the exposure is so short …there probably aren’t any houses right next to the radome though. Interference with a car implies plastic fenders, as metal fenders would act as a shield. Shade-tree mechanics should be able to bend sheet metal (part of an old heating duct?) around the computer box and ground it.

The computer in this vehicle is already shielded and putting aluminum foil over a steel fender isn’t going to help. Its the wiring between the computer and the engine that isn’t shielded.

If the computer is inside the cabin of the vehicle, it is somewhat shielded by the cabin, except for those windows. If the windows are not already tinted, she could have them done with a tint that has a high metal content. Other than that, she could wrap the wire bundles in aluminum foil and ground only one end of the foil. Or she could buy the ferrite cores but I think the foil would work better.

She should only need to wrap the wires from the computer to the firewall. The wires under the hood should be shielded by the fenders and hood.

This is apparently a radar tower, likely using microwave. As said before this is not ionizing radiation, so this does not cause cancer. It’s just highly directed radio waves. Yes it’s like microwave and can cook things but at several hundred feet it won’t cook anything. But apparently Isuzu and perhaps other cars are not shielding the car’s computer from this “noise”, making an inadvertent radio out of car electronics. And the car doesn’t really like to listen to radio, in fact it probably is getting really confused.

The aluminum foil idea is actually somewhat sound, but the placement I’m not sure about. The car is made of what, it’s also made of metal. Shielding the fender probably doesn’t help much. What needs to be shielded with the foil is stuff that not already shielded… namely, windows… but that sort of makes it hard to see. Ideally need to foil (and connect to the rest of the car) electronics like the car’s engine control computer and also any long wires that come from sensors like the crankshaft/camshaft sensors.

The ferrite cores could also help, again the sensor wires would be a good target. Unfortunately it could affect operation of the car as well.

That is an Air Route Surveillance Radar used by the Air Force and FAA for airspace monitoring and incursions:

Site Z-231

Check out the google street view of this thing!

I thought it was funny when I heard the show. I lived in that area for a long time and its not just isuzus that get zapped…
I had an 85 Ford F150 that it happened to. We pulled off the heat shielding insulation,put in mylar emergency blankets and replaced the heat shield insulayion. No more problems. Since then I do the same with all my vehicles. Basically turn the engine compartment into a Faraday Cage. Theres quite a few radomes around TX in the back country.

I used to have a trooper and one thing I remember is the computer is under the console between the front seats. So the radar pulses can come right in the windows and hit the computer and wiring.

I’ve worked on that particular radar facility. Inside the dome is an ARSR array antenna. It looks similar to the snow-plow shaped spinning radar antenna you would typically see at an airport - Only Much bigger. As the antenna inside the Keller TX dome rotates, it emits a beam centered at 1.25 GHz that is roughly 100 MHz wide (from 1.2-1.3GHz) at an output power of 4 million WATTs (which is extremely powerful). This site was built in the 1960s (newer radars require much less output power). It can detect low-flying aircraft at a distance of ~250 miles.

The site is owned and operated by the FAA, but the tracking data that it acquires as it sweeps the skies is fed both to the FAA for air traffic control and to the United States Airforce / Department of Defense for military purposes. This co-stewardship was made possible under the Joint Surveillance System (JSS) program which allows the Airforce to be directly plugged directly into the FAA tracking network.

There are roughly 100 JSS sites across the lower 48 states in the USA. However, many have updated, lower power radar transmitters (some have no radar at all). Most of these sites are located in very rural areas, or on current/ former military installations.

I was quite surprised to see, not only the fire station in such close proximity to the radome when I first visited the site, but several homes which appear to be even closer to it than the fire station is. As an electrical engineer, I am somewhat concerned (but not alarmed) about these stories of cars breaking down near this facility, given the 4 megawatt output power of the system.

There are some pretty good comments here from folks. Good RF stuff from Techguy19000. I wonder if the site was tracking the UFO shown in the picture provided by Chrissais-lol.

I agree with others that stated putting in some ferrite cores at strategic points would most likely solve the trouble.

4 megawatts, thats probably around 4 kilowatts average power. Thats way to close to a road for that kind of power. I’ve seen a 1kw average power radar light up steel wool at 75 feet, but that was with a pencil beam where this one is a fan beam. But that still a lot of power to be that close to the road.

techguy19000 , don’t know if you are from the area, but my brother lives kind of near there, and the amount of development in the last 10 yrs or so has been well, crazy, so it wouldn’t surprise me in the slightest, if when that installation was built in the 60’s, it was WAAAAYYYYYY out in the sticks, but that area has boomed and sprawled that much since the 70’s.

Here is the aerial view of the site. That is going to make a great science project!

It would be fun to drive by with an old fluorescent light tube and watch it light up every time the radar sweeps by.

It takes a significant electromagnetic field intensity to interrupt a car this way, though the Isuzu in question could be more susceptible than most. Complexity in cars started in the early 1970s when they started installing electronic ignitions, so a pre-1973 or so car would not likely be bothered by the radar.
One thing I’m fairly sure of in response to an early comment; No new car dealership is likely to have the slightest idea of how to resolve this issue…

If the caller would happen to read this page, according to the Mechanics Files Listings, there is a shop in Farmers Branch(approx 20 mi. away) that Specializes in Honda,Infiniti,Isuzu,Lexus,Nissan,Toyota

Tokyo Town -
3607 Garden Brook Dr.
Farmers Branch TX, 75234
(972) 241-1911

Features and Specialties: Offers loaner cars ,Has ASE certified mechanics ,Guarantees all work for at least 1 month or 1000 miles ,Happily gives binding estimates