On Feb 14, 5:31�am, Al wrote:
" wrote:
On Feb 13, 4:02?pm, wrote:
On Feb 12, 6:17 pm, "KE5MBX" wrote:

Hi,
What's all this business I hear people talking about blasting people's
car stereos or killing cars altogether with high-power RF? I run 2m,
10m, and 11m in my jeep and I'd like to sort out the fact from the
legend and find out what kind of power I can use without risking
damage to my jeep or cars around me. *At what power level is front-end
overload to a nearby radio likely? At what power level is damage
likely, and to what componets?

I am currently using only 50 watts on a 5/8 wave (2m), 25w on a 1/4
wave (10m), legal 4w on a 1/4 wave (11m)

Thanks,
Nelson KE5MBX

There are many times when "high" power has disrupted other devices.
The early car computers have been know to shut down with 100 watts of
VHF. Worked on a police car that the engine would shut off when over
80 mph and key the radio.
*A friend would be taking on his 1KW mobile as he pulled into his
driveway. He would find his base radio receiver front end blown. Took
three times to think it through and as he should have been doing,
switch his base antenna (dipole over the driveway) to ground, when not
in use.

* *Isn't that just ordinary RFI/EMI that can happen in a house
* *environment? *:-)

* *Don't expect auto makers to RFI-proof their wiring without an
* *extra kilodollar add-in to the sticker price.

*

In Montana, there was a Sage radar, 5MW pulse power, which would zap
your car radio when the beam crossed it. Fortuneatly this was in the
60's before the electronics control of your car's engine. The solution
was to tilt the radar antenna up 5 deg. so both the town and the highway
that passed in front of it were not impacted. Even so, I have tape
recordings from that era which have a little zap in the every 12 secs as
the lobes passed through town when the antenna rotated. Oh yes, and
before the antenna was tilted, flourescent lights would also blink.

The flourescent lights blinking on by themselves and buzz
tones in the 16 mm motion picture projectors' audio were
common at the Radar Basics classrooms of Fort
Monmouth, NJ, in 1952. The high-bay where 1 MW peak
pulse search radars were set up were constantly annoying
the instructors across the street in the classrooms. shrug
Got annoying to the students too.

But, none of that was in the league of "frying auto electronics"
nor any real danger to humans at a half block distance.