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By Ed Hare, W1RFI, ARRL Laboratory Supervisor
Installing mobile radios in your new megabucks car can be a frightening proposition - especially if RF from your rig could damage your shiny new roadster, voiding the warranty! Want help? Read on!
Sidebar: Society of Automotive Engineers EMR and EMI Standards Committee
[BMW] [Chrysler] [Ferrari] [Ford] [General Motors] [Honda] [Hyundai] [Isuzu] [Mazda] [Mercedes-Benz] [Mitsubishi] [Nissan] [Peugeot] [Porsche] [Saab] [Subaru] [Suzuki] [Toyota] [Volkswagen] [Volvo]
In the good old days, things were simple. If you wanted to install a mobile radio in your car, your primary considerations were mechanical: where to place the antenna, where to mount the radio and how to route the wires so they didn't interfere with the family use of the car.
There were some incompatibility problems to solve, such as electrical RF noise from the ignition system, but the proper application of cures (resistive wires and plugs, or, in extreme cases, a filter for the distributor and its wiring) almost always resulted in a successful installation.
As automotive designs evolved, however, installing mobile radio systems became more complicated. Remember how computers used to be house-sized monoliths? In the early 1980s, microprocessors and their associated circuitry became small enough (and inexpensive enough) so car manufacturers (and many others) could use them to control many different functions.
In the early 1980s, electronic control modules (ECMs) became standard in most cars. There were sporadic reports of interference problems to and from these devices, but most hams were able to find a work-around. Soon it became possible to use microprocessors to accomplish additional automotive functions, ranging from engine control to anti-lock braking to air-bag deployment. Some manufacturers even use "slave" microprocessors to control things such as rear-end lights, running only one cable to the back instead of an entire wiring harness, using the "slave" microprocessor to execute proper tail-light sequence (brakes, signaling, etc).
Sure enough, these electronic marvels came with a price!
The more complex things become, the more likely it is that things will go wrong.
Every microprocessor has a clock oscillator, and the circuitry uses digital signals for processing and control. These digital signals are square waves. They're perfect for digital circuits, but rich in harmonics.
FCC regulations (Part 15) specify the amount of interference that can be generated by these "unintentional radiators." The regulations are adequate to protect other radio services, such as TV reception in nearby homes, but they're not intended to protect against interference to radio receivers installed in the vehicles, broadcast band or otherwise.
In addition, the vehicle electronics can also be affected by strong electromagnetic fields (EMFs). These fields can be caused by nearby transmitters, transmitters installed in the vehicle, high-voltage power lines, and so on.
Most manufacturers created electromagnetic compatibility (EMC) departments to deal with testing and design issues, assuring compliance with federal regulations and compatibility with factory-installed equipment.
In addition, the industry has voluntarily developed standards that apply to many EMC technical issues (see the sidebar on the Society of Automotive Engineers). There is even a standard that applies to installed transceiver equipment. (The ARRL is a voting member of the SAE Committee working on these standards.)
So far, things look pretty good! New technology has made cars less expensive, more reliable and less polluting. Federal regulations control the amount of interference that cars can generate, automobile manufacturers have created departments to solve the problems and the entire industry has formed committees and developed standards to help make things right.
As automotive designs evolved, ham gear did, too. More and more ham transceivers were capable of operating from a 12 to 14-volt supply, so mobile operation became more popular than ever.
Unfortunately, this rosy picture was spoiled by an unexpected phenomenon; radio transmitting equipment, sensitive receivers and automotive electronics didn't always work well together.
As if this weren't bad enough, EMC problems usually take place on a two-way street (all puns intended). Just as vehicle electronics can interfere with installed radio equipment, even low-power transmitters can interfere with vehicle electronics.
Details are not forthcoming, but urban legends abound about vehicles that would stall or lock their brakes near high-power transmitters, or about hams who could stall nearby vehicles on the highway by keying up high-power transmitters. (The ARRL staff has amassed a fair collection of anecdotal reports, none of which describe this problem firsthand.)
The legends may or may not be true, but vehicle manufacturers know that fields of up to 300 V/meter can be found on our highways and byways; automobile electronics must continue to function when drivers whiz past Voice of America transmitter sites!
Car companies have worked to ensure that their vehicles do not interfere with factory-installed equipment and do not keel over near VOA-class transmitters, but it's clear that manufacturers do not always pay attention to compatibility with after market equipment, including transmitters and receivers for various radio services.
When hams installed transceivers in their cars, things didn't always work as planned. As the number of automotive microprocessors grew, the potential for the umpteenth harmonic of the clock oscillator falling on a favorite repeater channel also grew. Add to this the possibility of noise from sophisticated ignition systems, motor noise from wiper-blade, electric cooling fan or fuel-pump motors, and even the vehicle's factory-installed broadcast-band radio receivers and you have a potential for electromagnetic incompatibility.
What's worse, some vehicle electronics are susceptible to RF fields generated by mobile transceivers. This susceptibility ranges from the minor annoyance of having a dash light come on in step with the transmitter, to the major annoyance of having the vehicle's microprocessor lose its mind, resulting in a dead car.
The ARRL has not received any reports about interference to safety devices such as anti-lock brakes or air bags, but this type of interference is still possible, especially if good installation techniques are not used.
In early 1992, John Harman, W8JBH, wrote an item for QST's Correspondence column pointing out the problems he was experiencing in trying to get Toyota to help him with an interference problem he was having with his 1992 Camry.[1]
In Harman's case, his 2-meter transceiver had resulted in temporary damage to the car's ECM. John, as of that date, had been unable to get any concrete information from Toyota about the proper installation of transmitting equipment in his vehicle.
Since then, we've heard from other hams who experienced similar interference. The May 1992 issue included a few more tales of woe. In addition, the ARRL Technical Information Service and RFI Desk heard from a few dozen folks who had been having some sort of EMC problems with their cars, dealers or manufacturers.
This is, of course, just the tip of the iceberg; most hams simply do not report their interference problems: not to the FCC, the involved manufacturers or the ARRL.
The situation was confusing. After hearing tales of blown ECMs and voided warranties, hams were afraid to install mobile transceivers in their cars. As interference reports increased, the Lab decided to look into the matter.
As ARRL Senior Lab Engineer and all-round EMC guru, the task fell into my lap. "No problem!" I said. "We can ask car manufacturers to tell us all about their cars and policies." I drafted a letter asking the following questions:
We also outlined some typical Amateur Radio installations, citing power levels of 100W on HF, 50W on VHF and 10W on UHF.
I sat back and waited for a flood of responses from a field of eager manufacturers. I knew that each would tell me that it was okay to put transmitters in their cars and that if hams had problems, dealers and customer service people would be glad to help them out.
The replies would lead to an article summarizing the responses that would clearly explain how to install a radio in each type of car and reap the praise from all of our grateful members. NOT! (Well, not exactly, anyway.)
After 60 days, we'd heard from only a handful of manufacturers. The first round of responses didn't look very useful, with the letters ranging from "We have never had a problem with radio installations," to "It's not our fault - ever!" The latter is paraphrased, but not too far off the mark.
Things weren't going to be as smooth as I had hoped. I waited impatiently another month and sent off a follow-up letter, asking what happened to the first letter, and pointing out how the manufacturer was going to look if it did not respond and were listed in a national magazine as having ignored two letters.
Over the next 90 days, the answers trickled in. In many of the letters I could clearly see the mark of the manufacturer's marketing, public relations and legal departments. The caveats were rampant, and in most of the letters the disclaimer that if any after market equipment, including radio transmitters, caused any damage to the vehicle would not be covered under warranty.
One company said the answers to the questions I had asked were proprietary! Even worse, some companies didn't respond at all! In most cases, I finally got a response by calling the respective public relations departments.
To partially offset the number of companies that didn't respond, one company sent two answers - completely contradictory, of course. The mix-up was ultimately resolved, but it demonstrates that a big part of the EMC problem may involve poor communication.
A company can have an excellent EMC facility, program and policy, but if its information isn't widely distributed to dealers and regional offices, it does little good.
If QST received contradictory responses from the same building within the same company, imagine how difficult it could be to get accurate information from corporate and engineering policy makers at the factory to dealers who have to actually solve the problems.
So far, the overall manufacturers' response hasn't been that good. It isn't all bad, however. I noticed several call signs in the signatures of the letters I received. Not surprisingly, these were among the more useful answers.
A few of the companies came quite close to my ideal, giving us solid information and telling us that their dealer-support network or factory specialists will help hams with compatibility problems!
Toyota, the company whose customer really started the ball rolling, did respond after much prompting (not unlike John Harman's experience). And after all was said and done, Toyota's response was actually positive. It took a bit of time, but for the 1994 models, the 10-W power output limitation mentioned in the 1992 Service Manual has been upped to 100 W. According to Toyota's Customer Service Department, a few of the 1994 manuals were not updated, but the current limitation of 100 W applies across the board.
General Motors has long been proactive in the EMC field, maintaining a complete EMC facility (like many other automobile manufacturers), publishing a complete and useful installation guide and maintaining a high profile in the professional and amateur EMC press.
Even more encouraging is the fact that several companies told me privately that my letter and article have prompted them to develop their own EMC guidelines and to clarify company policies about EMC.
Unfortunately, there have been problems even with some of the companies that have clear policies and installation guidelines. In several cases, hams who have reported problems tell us that customer-service people or dealers made decisions that were different from the information that we received in writing from the manufacturer.
When I called the Customer Assistance Center at Pontiac, as a follow-up to Member who called me, at first I was told the same thing as the Member - that they had no information about how to install radios in cars. Everyone I spoke with at the assistance center insisted that the dealer is the only source of information.
Remember, GM is one of the good guys! They have an active EMC department, published installation guidelines and clear policies. Unfortunately, the process often breaks down.
All in all, the problems are not surprising. Many auto manufacturers are giants, and it must be difficult to maintain a clear policy in all areas across such a diverse and spread-out business structure. On the other hand, our original letters were sent directly to each company's customer-service contact address.
Of course, all of the policies could be swept away by the new model year! As each new model is designed and built, its EMI susceptibility presumably will be different than its predecessor. Because most manufacturers won't guarantee that a properly installed transceiver will not interfere with a vehicle's proper performance, we could never keep track of the changing policies and applications.
Clearly, manufacturers have a way to go before the policies and standards formulated by their hard-working EMC engineers and EMC committees can make a difference for the average ham. The ARRL will continue to work toward that goal - and you can help! If you've had interference problems with your automobiles, or good or bad experiences with your dealer in getting those problems resolved, report this to the manufacturer at the address we list at the end of the article. This will help manufacturers to stay on top of the types of problems their customers are experiencing.
Send a copy of your letter to:
I will collect the letters, combine them with what we already have, and send them en masse to the key players at automobile manufacturers and their standards committees.
Let's see how we can make a difference. If all else fails, contact me at HQ with your automotive EMC problems.
Now, as promised, a description of each manufacturer's policy statement. The addresses and telephone numbers are the manufacturers' suggested contacts or are the addresses on the letterheads of the letters we received from manufacturers. All of this information is based on the statements made by the vehicle manufacturers. Manufacturers not listed were not contacted. If the manufacturer answered our question about who to contact to resolve problems, we have included that in their response. If not, contact your dealer or the manufacturer's customer-assistance network. Most manufacturers suggest that customers contact their dealers, who have access to the normal problem-resolution workers through zone or regional offices, which, in turn, contact the factory for support with difficult problems.
BMW does not test their cars for the installation of the types of radios we mentioned (ham HF, VHF and UHF transmitters). They cannot comment on the transmitters' compatibility with BMW products. However, the electronic systems in their vehicles are designed to be protected from EMI sources outside the vehicle. A specific repair would not be covered under warranty if it were determined that damage was caused by the installation or operation of any non-approved after market accessory.
Chrysler has an extensive EMC program, involving design, testing and active participation in the development of national and international standards on EMC for the automotive industry. They support the power levels described in SAE J551/12 (typically 100 W - see the sidebar). For 1992 through 1995 model years. On new vehicle orders, specify the JLW sales code to obtain a vehicle with a suppressed ECM.
The owner's manual of a new Chrysler product contains a summary of their EMC policies. The design of the vehicle provides immunity to radio-frequency signals. Two-way radio equipment must be installed properly by trained personnel. Power connections must be made directly to the battery, fused as close to the battery as possible. Antennas should be mounted on the roof or rear of the vehicle. The antenna feed line must be shielded coaxial cable, as short as practical and installed away from vehicle wiring. Ensure that the antenna system is in good order and is properly matched to the feed line.
Chrysler has published a comprehensive installation guideline, expanding on the guidelines in the owner's manual. Any Chrysler dealer can supply or order a copy (order no. TSB-08-31-94). The guideline describes in detail the mechanical, electrical and RF requirements that need to be considered for a successful radio installation.
All of this withstanding, Chrysler warranty does not cover any non-Chrysler parts or the costs of any repairs or adjustments that might be needed because of the use or installation of non-Chrysler parts. The owner's manual details the policy that should be followed to resolve any customer problems that can't be corrected by the dealer. Chrysler had a booth at the 1994 Dayton HamVention, answering customer questions, passing out literature, and soliciting customer feedback.
Ferrari North America is a distributor for its parent company in Italy. It did not have much information available, but stated that any vehicle damage caused by the installation of any after market equipment would not be covered under warranty. At press time, the New Jersey office was still awaiting information from engineers in Italy.
The electronic modules and entire vehicle are subjected to conducted/radiated immunity levels testing. These tests are designed to reflect the use of 100-W class transmitters installed in the vehicle and verify that their operation causes no damage to any system and that critical safety systems will not be functionally affected during exposure. Tests are also done to minimize interference with radio reception.
However, Ford cannot guarantee freedom from interference from all possible installation configurations. The installation of such equipment does not necessarily void the warranty, but if the installation is determined to have caused damage, such damage would not be covered. (Ford engineers say they do test for the installation of on-board transmitters.)
Ford is not aware of any damage problems from Amateur Radio equipment. If problems are experienced, first contact the installer or supplier of the ham equipment to see if a different installation procedure will correct the situation. If that doesn't work, contact your dealer, who has access to Technical Service Bulletins (TSB) and technical support. There is a TSB (93-15-6) on the installation of a filter to reduce interference from the electric fuel pump (reports received at ARRL are mixed; for some hams it worked, for others it didn't). According to Ford, these TSBs are only recommendations and are not guaranteed to work.
In 1987, the Ford Electrical and Electronics Division wrote an installation guide (Tech Letter EED-6-031 -N). This was not mentioned in Ford's 1992 letter to us, so it is probably obsolete.
General Motors Contact Information
Each GM subsidiary has its own customer-service network and TSB numbers or installation guidelines. These guidelines represent the only official EMC policy of General Motors. The following is taken from GM installation guidelines:
"Certain radiotelephones or land mobile radios or the way in which they are installed may adversely affect vehicle operations such as the performance of the engine and driver information, entertainment and electrical charging systems. Expenses incurred to protect the vehicle systems from any adverse effect of any such installation are not the responsibility of the General Motors Corporation." The following are general guidelines for installing a radiotelephone or land mobile radio in General Motors vehicles. These guidelines are intended to supplement, but not to be used in place of, detailed instructions for such installations which are the sole responsibility of the manufacturer of the involved radiotelephone or land mobile radio.
"If any vehicle-radio interaction exists after following these guidelines, check current service bulletins for resolution of the customer problem. If there is no bulletin that covers the customer problem, call your technical assistance group." [This is apparently an instruction to the dealer. - Ed.]
Locate the transceiver for remote radios on the driver's side of the trunk. One-piece transceivers should be mounted under the dash or on the transmission hump. Don't mount any accessory in the deployment path of the air bag. Mount antennas in the center of the roof or center of the rear deck lid. Use a high-quality coaxial cable, located away from vehicle electronics. Tune the antenna for an SWR < 2:1. Obtain power directly from the battery itself, properly fused, for both positive and negative leads. Use connector kit 1846855 (GM and AC-DELCO) to connect to the battery terminals. Route all wires through grommeted holes in the front bulkhead.
As an editorial aside, General Motors and its various subsidiaries have long been active in the EMC field. They have had a booth at the annual Dayton HamVention to gather customer feedback and to issue information about their automobiles. They were one of the first companies to publish installation guidelines.
In general, hams should not experience problems with the installation of transmitters in General Motors vehicles. Their guidelines outline the approved methods to install transmitters in their cars. GM design engineers test the installation of on-board transmitters.
According to Honda, the installation of amateur transceivers has not presented any problems. If a customer experiences a problem, Honda will refer the customer to the original installer or manufacturer of the installed equipment. The installation of an after market transmitter would not necessarily void the warranty, but if the installation were not done properly or damage were caused by a defective after market component, it would not be covered.
Hyundai has an extensive EMC test facility at its factory in Korea. They have not experienced many problems with properly installed, medium-power transmitters. Their customer-service engineers have been able to work successfully with their dealers to straighten out any problems that have been encountered. They do not have any published installation guidelines, but suggest that a proper installation would keep power and antenna cables well away from the ECM and its wiring, obtain power directly from the vehicle battery and ensure that the antenna were properly tuned and installed, well away from the ECM. The ECM is located just behind the kick panels on the left or right side of the vehicle. Customers who experience problems should first carefully evaluate the installation, then, if necessary, contact their dealer. Dealers have access to Regional Offices and the National Technical Services Department for assistance in resolving customer problems. This information was supplied in 1992. As of press time, they had not yet answered a request to verify the information as being applicable to the current model year.
The installation of radio transmitters has not been tested by the parent company in Japan, so Isuzu does not have any information. Their policy letter is clear: "Any modification to your vehicle could affect its performance, safety or durability; void the warranty; or even violate government regulations." [Apparently this policy was intended to cover more than just ham radio transmitters. - Ed .]
In a conversation with ARRL, the Customer Relations Manager was quite clear; they deal with only unmodified Isuzu vehicles. Problems with the installation of transmitting equipment; fall outside the scope of their customer service responsibilities.
No answer was received to two letters and three faxes sent to Mazda's "Customer Relations Manager." A letter to the Public Relations Office prompted a phone call from Mazda's Customer Service Coordinator, who promised an answer within "two weeks." As of press time (about two months later), the answer had not been received.
Mercedes-Benz Contact Information
Mercedes-Benz says that it is generally acceptable to install moderate-power transmitters in their cars, provided the installation guidelines outlined in their Service Information MBNA 54/35 are followed. Customers having problems should first contact their dealer, who will then contact the nearest Regional Office. The Regional Offices have received training and information about how to resolve interference problems. Dealers or customers can also contact the Customer Assistance Center at the toll-free number listed above. Mercedes-Benz is committed to providing reasonable technical assistance to their customers. They have an extensive laboratory and field EMC testing program.
Mitsubishi Contact Information
The installation of after market equipment does not necessarily void the warranty, but if the after market equipment causes any damage to the vehicle, that damage will not be covered under warranty.
All requests about EMC problems should be directed to the above office. The staff is not specifically trained in EMC, but will direct inquiries to the correct departments. Poor installations that do not follow the Nissan installation guidelines and high transmitter power can cause malfunctions and/or damage to electronic control systems of any vehicle. While the installation of a radio in and of itself will not void the warranty, any expenses incurred in protecting the vehicle's electronics from a radio installation are not the responsibility of Nissan Motor Corporation.
They did supply a copy of an installation guideline. The guideline emphasized the following points:
Peugeot has ceased production of US models after the 1992 model year. They recommend against the installation of transmitters in their vehicles. Their ECMs are not shielded adequately to protect against the resultant amounts of EMI. which may interrupt or damage their operation. If damage to a Peugeot vehicle is determined to be caused by an outside influence, the damaged component would not be covered under warranty.
Porsche "prohibits the installation of radio transceivers and any after-market electric equipment in new Porsche vehicles" They "discourage the addition or use of non-Porsche supplied telephone equipment in the vehicle."
If transmitters are operated within their cars, control or warning lamps may light up with no apparent reason, or malfunctions may occur in other electronic components.
All Saab vehicle designs have been EMC tested. Individual questions about frequency and power can be answered by their Customer Assistance Center. All inquiries and problems are handled on an individual basis. They have no record of any EMC problems with Saab cars. The installation of after market accessories will not void the vehicle warranty, but if the installed equipment causes any damage, that damage will not be covered under warranty.
According to Subaru, they have not experienced any problems with the installation of on-board transmitters. If any problems are experienced, the customer should contact the dealer. If the installation of any after market component causes damage to the vehicle, that damage would not be covered under warranty. This information was supplied in 1992. Subaru Customer Service and Public Relations did not answer several faxed requests to verify the information.
Below is a reply from Subaru to a customer inquiry.
Q. I am looking for a point of contact on Radio Frequency Interference (RFI) problems. I am a Amateur Radio operator and have radio equipment in my Outback. I am experiencing RFI in the 10 to 30 Mhz range and with test equipment we have determined that the generation point is from the Instrument pod area. Is there someone who can help with this problem?
A. From: SOAMail@sun.subaru1.com
Sent: Friday, August 11, 2000 8:49 AM
We generally don't recommend transmitting devices be installed in our vehicles because they could cause interference, and should you have a security system the radio may cause it to set off. This being said, we have heard from some Subaru owners who successfully have used their amateur radios in our vehicles. If you decide to do so, we suggest that you have it properly mounted as far as possible from the Electronic Control System, and that you take all the necessary precautions to eliminate interference.
Also, please note, any etching on the glass can weaken the integrity of the rear window. There is a UV rating, but no tint is on the glass.
For further assistance, you may contact your Subaru Service Manager for assistance. I hope this information is helpful, and thank you for taking the time to contact us.
Pam Federer
In 1992 the Suzuki Customer Relations Manager told us that the answers to our questions were "proprietary." This was clarified a bit by the additional statement that "American Suzuki Motor Corporation does not recommend any modifications or (non-Suzuki) parts or accessories." Two follow-up letters and two separate faxes for clarification went unanswered. Suzuki's Public Relations Department told us via telephone that "proprietary" was not a good choice of words. The intent of the original letter was to be clear that Suzuki will not support or endorse the installation of any after-market equipment and that any problems resulting from after market equipment will not be covered under warranty and should be resolved by the after market manufacturer.
Subaru of America, Inc.
Suzuki, American Suzuki Motor Corporation
Toyota Motor Sales USA, Inc
Toyota is well aware that there is a sizable group of ham radio enthusiasts in the U.S. market. In fact, per capita, that population is even larger in Japan. Obviously, we would not intentionally turn our backs on these potential vehicle buyers.
As you know, the operating systems in today's vehicles are controlled by a growing number of very sophisticated electronic control modules. Most of these ECM's utilize MOSFET technology, which can be easily damaged by electromagnetic radiation from high power radio transceivers and associated system components.
Understandably, Toyota and the other automotive manufacturers have to be concerned about such potential problems, because they could affect the operation of electronic systems that control vital vehicle functions such as the ignition system, fuel management system, supplemental restraint system, cruise control, anti-lock brakes, and others. The very conservative position stated in selected Toyota technical manuals recognizes that, as the vehicle manufacturer, we have no control over the wide range of variable circumstances and unforeseen conditions that could be involved in the after-sale installation and operation of those system components.
In a "worst case" situation, vehicle electronic components could be damaged, and/or the proper and safe operation of the vehicle might be compromised if, for example, any of the following situations (and potentially others) existed:
- The transceiver is not "type-accepted."
- The power and/or antenna cables radiate RF current.
- Routing of the power and/or antenna cables results in inductive or capacitive coupling.
- Transmitter, feedline and/or antenna inefficiencies result in an unacceptable level of, RF radiation exposure to the ECM's.
- The standing wave ratio is unacceptably high.
- The antenna ground plane is inadequate.
We can understand your interest in obtaining information from Toyota that would provide detailed recommendations on how to properly install ham radio components in our vehicles or, conversely, how to avoid specific potential problems. As a result of several inquiries such as yours, Toyota Motor Sales, U.S.A., Inc. petitioned our parent company in Japan to provide as much information as possible that would assist ham radio enthusiasts in making informed decisions.
Their response provides basic installation guidelines (outlined in the attachment) which we trust will be of assistance to you. Although it may not fully answer all your specific requests, Toyota must take reasonable precautions to limit our potential legal liability, because the full range of possible variables noted earlier could never be fully anticipated. Also, more detailed information that would provide the operational details of Toyota's electronic system is considered proprietary.
Contacts such as yours are always welcomed, because it allows us to monitor specific consumer interests in the U.S. market. Thank you for the time you have taken to call us, and your interest in Toyota vehicles.
Attachment
2-WAY RADIOS IN TOYOTA VEHICLES
Installation of a 2-way radio in Toyota vehicles should not present problems under the following conditions:
* The transceiver must be type-accepted by the FCC, and not modified in any way.
* Maximum output power complies with FCC regulations (100 watts).
* All installation and operating instructions provided by Toyota and the equipment manufacturer must be followed closely.
* The antenna must be installed as far away as possible from all vehicle electronic control modules (ECM) or other onboard computer/sensors.
* The antenna cabling must be routed no closer than 20 cm (7-7/8 inches) to any ECM or other onboard computers/sensors.
* Antenna and power cabling must not be routed along side or in conjunction with the vehicles wire harness. It is always preferable to cross vehicle harness at right angles when possible. Antenna and antenna cabling should be properly adjusted to obtain the lowest possible standing wave ratio (SWR).
It must be emphasized that, under the terms of Toyota's new vehicle warranty, and damage caused by RF energy from a higher power mobile radio is specifically excluded from coverage because it is not the result of faulty materials or workmanship. Accordingly, all such responsibility is assumed by the owner.
Volkswagen Contact Information
All Volkswagen designs are thoroughly tested for EMC at their test facility in Wolfsburg, Germany. In addition, the vehicles are extensively tested in the field for RF exposures to fields greater than 120 V/meter. At the present time, the minimum requirements for passing their tests is 120 V/meter for 3 to 30 MHz and 80 V/meter for 30 to 1000 MHz. Critical safety components are tested over a wider range of frequencies at higher field strength. They have no reports of problems from using radio equipment in their vehicles. Their Corporate Technical Services Department is confident that they can advise hams that encounter problems.
Volvo builds and tests vehicles to several international EMC standards. They feel that their cars are generally safe regarding immunity against EMI from properly installed transmitters. Volvo tests their vehicles with transmitters with frequency range from 1.8 MHz to 1 GHz, using 10 different antenna locations. Volvo requirements are that the vehicle performance shall not be affected by transmitters in the 200-W range and that no system in the car shall be damaged by a field strength of up to 200 V/meter. This information was received in 1992. Several requests to verify the information for current model years were not answered.
The automotive industry is quite concerned with automotive EMC issues. The Society of Automotive Engineers formed the EMR and EMI Standards Committee to coordinate and supplement the EMC work being done by individual manufacturers. This committee is still in existence today, with representatives from automobile manufacturers, component suppliers and consumer groups. Ed Hare W1RFI represents the ARRL and Amateur Radio officially on this committee, but there are several hams on the committee who also understand the radio communications aspects of the work and projects of the committee. The committee is publishing a new set -of EMC standards for automobiles. SAE J55~ which pertains to complete vehicle EMC tests, was first published in 1957. The document established a test method and limits for broadband radiation from ignition systems. It has been revised several times over the years to keep pace with changing technology.
The latest version, now in printing, includes a-new test to measure the amount of RF energy arid-noise picked up on an antenna mounted on the vehicle. It also includes test methods for measuring the immunity of the vehicle to strong RF fields. Three immunity tests are included: off-vehicle radiation source, on-vehicle radiation source and a bulk-current injection test method. Of particular Interest to ,amateurs Is the Eon-board transmitter simulation test method. The amateur bands from 1.8 to 1300 MHz are included; power levels are typical of commercially available equipment for each band.
A second series of documents, SAE J1113, also in preparation, includes emissions and immunity tests for modules and components used in vehicles. Originally, this document only contained immunity tests, but the scope was expanded during development to include emissions as well.
A task force of the SAE EMR Standards Committee is developing test methods will have a significant impact on the design of integrated circuits (ICs) used in vehicle electronics. Improvements in the layout of ICs have been defined that will reduce the RF energy the microprocessors and other digital ICs will emit. While the focus of this standard is on automotive needs, it can be applied to ICs for all applications.
The work of the SAE committees is international in scope. SAE delegates represent the United States on two international standards committees that are chartered by the UN. The Special International Committee on Radio Interference (CISPR, from the French version of the committee name) deals with interference to radio reception. A working group of the International Standards Organization deals with the immunity characteristics of automotive vehicles. The SAE standards and requirements are closely aligned with the international standards.
It has taken several years to complete the work that went into these standards. The needs of Amateur Radio and other on-board radio services have been seriously considered as these standards have been developed. As manufacturers' engineering teams use these standards to develop new automobile designs, many of the problems reported by hams will no longer be a major concern.
-Poul Andersen, K8JOF, SAE EMR and EMI Standards Committee Chairman
