Crazynorwegian, you caught the word from one of the two best knowledge bases for this question - the Ham Radio guys. Most Ham operators go out and buy vehicles based on "the manual"; not just what they think would be a good ride for their purposes. Radio gear and ECU's very often do
not mix! And it doesn't even have to be a lot of power. The wife's Grand Prix (I
hated that car for many, many reasons) had a fit every time I keyed up my Ham gear - 60 watts on VHF or only 45 watts on UHF would cause the (electronic) speedometer to "drop" 10MPH at highway speeds. This was funny, until I keyed up the radio when rounding a bend into a speed trap....the cruise control "read" the speedometer and guess how much "too fast" I was clocked at?
Just walked out to the carport and opened up the first vehicle I came to. Everybody should take SD's timeless wisdom about RTFM. From the inside back cover of the 2003 Dodge RAM (wife's truck) owners manual:
"Special design considerations are incorporated into this vehicle's electronic system to provide immunity to radio frequency signals. Mobile two-way radios and telephone equipment
must be installed properly by trained personnel. The following must be observed during installation"
{Follows are 4 paragraphs regarding DC power and antenna routing. Boring stuff, if you've done it for a living (I have); but, if you haven't.....
Then comes these two fun little paragraphs}
"Mobile radio equipment with output power greater than normal may require special precautions."
{Yeah, 1kW would be considered "output power greater than normal" for a mobile installation)
"All installations should be checked for possible interferencebetween the communications equipment and the vehicle's electronic systems"
The book on the Generic Rice-Eating Chevy Truck says much the same.....and for those die-hards out there; tomorrow I'll grab the book out of the work F150 so we can "Read The
FORD Manual". Bet it covers the same.
Don't want to hear from "the Amateurs"? You should read the tomes (means: "really big books") that take up a bunch of shelf space in your average
professional Motorola shop regarding EMI issues on various vehicles. The '90
Crown Vic covered all kinds of dire circumstances if you didn't follow the factory recommendations (key the mic, get a face full of airbag
); which basically read: "If you don't get the Police Pursuit Package, your gonna screw something up, period". If you think getting that fuel return line back to the gas tank on your 5.0 EFI equipped '66FB was a pain, try routing 3/4" EMT (bonded to the frame/unibody every 2-4 feet) from the engine bay to the trunk of the Chief's SHO! And we're talking about a car from a manufacturer which had a lot of years' experience with putting ECU's in in a lot of cop cars; which would naturally have more than the average amount of radio gear stuffed inside. By then, they already knew to install feed through capacitors and RF chokes in the fuel pump power lines and brake/turn light feeds - they learned it the hard way.
The theory is nice, but it sometimes doesn't live up to the real world.
Yeah, an early "computer-controlled" car could realistically get taken down by a 1kW HF amp. No problem. To quote somebody's sig line from a couple years back, "You Make It, We Break It. Guaranteed"
Still Dreamin'
And when it comes to Radio; I was a NABER cert. professional before I became an "Amateur" - Jimmy, KC7BDP