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

In article .com,
(known to some as KE5MBX) scribed...
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?

Some research with the Radio Amateur's Handbook, notably the
sections on field strength and RFI, coupled with what you should already
have learned during your license course study, should provide all the
answers you need.

Happy hunting.


--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute
(Known to some as Bruce Lane, KC7GR)
http://www.bluefeathertech.com -- kyrrin a/t bluefeathertech d-o=t calm
"Salvadore Dali's computer has surreal ports..."

On Feb 12, 3:17�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

If you are using TeraWatts of output power (unlikely) or wish
to detonate a nuclear device (for its EMP or Electro-Magnetic
Pulse), you are not going to blast anyone's rig or ruin their
auto boom-box or even harm their ignition from a ready-built
amateur radio rig.

As the good "doctor" said, your ham radio test should have
clued you in on what is considered "harmful" to humans.
How about reigning in some hysteria and folk tales and
concentrate on actual building-testing-slinging-solder
radio-electronics instead of some fantasy notions? :-(

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.

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 article .com,
" 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. Â*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.
Â*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.

Al

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.

On 13 Feb 2007 16:02:34 -0800, 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

Some thing wrong there. I'm running two stations here and both are
capable of the legal limit. The one in the shop is a bit more modest
with a 2K4 instead of an Alpha, but both are *old*. OTH there is the
whole Hallicrafters station in the shop as well. The antennas are
fairly close and there has never been a problem. Those antennas
http://www.rogerhalstead.com/ham_files/Tower30.htm (the wire antennas
are difficult to see) are much larger than what your friend would have
had on the mobile. Unless the mobile antenna was almost touching the
other rig's antenna and I do mean almost touching it shouldn't have
created a problem. The antenna over the driveway would have had to be
*low* and very close to the mobile antenna.

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.

I don't ground or disconnect any cables even during thunderstorms.
Basically I can't easily get to the cables and any thunderstorm would
be past by the time I could get them disconnected.

The tower, with a large antenna system
http://www.rogerhalstead.com/ham_files/Tower29.htmtakes an average of
3 visually verified direct hits a year although it took 5 by the
beginning of August last summer. OTOH I have a good single point
ground with 32 or 33 (lost count) 8' ground rods CadWelded (TM) to
over 600 feet of bare #2 wire that ties the whole antenna system and
house electrical ground together.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

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)

About 2 years ago I was in a rather frivolous mood, brought about by a drop
of absolute vodka. I wondered just how certain things reacted when put in a
750 Watt microwave oven.

I first tried a new way of burning a CD. Amid sparks and a pyrotechnic
display that appealed to my sense of ****edness, it sort of got crazy-paved.
After about 20 seconds I had to switch off the microwave because of the
stench.

Then I turned to more "electronic" things. A Fujian MP3 player bit the dust
instantly. Basically there was one huge "wooooofff!", then the PCB set fire
to the plastic case after about 30 seconds.

Then I tried an old hamradio rig. It was an old Trio (Kenwood in the USA)
2200GX, crystal-controlled rig, with a rubber-duck antenna, and a battery
compartment that had not held batteries for several years. I put it in as it
was, but without the mic. Battery door open, rubber-ducky antenna on.

It sat there for about 15 seconds before anything happened, then the front
panel sparked a bit and caught fire. The front panel looked similar to the
CD, but a bit more melted-down, and the knobs had changed to a totally new
shape. But apart from that, the radio itself still worked fine after a 30
second 750W cook. It just looked more of a mess then it did originally.

Out of interest I tested it. I was expecting RF to get in the antenna and
coarse its way through the PCB, but no! The RF sensitivity was 1.25uV PD for
20dB sinad. Perhaps that was 10dB down, but it was still quite useable The
TX was still delivering 1.5 Watts.

I took off the case and tried again, and THAT killed it for sure. After only
10 seconds the PCB "whooffed", with loads of sparks and spitting.

But the point is that you cannot couple more power into a rig than that,
even with the cover on. The antenna was connected, and 750 W did not kill it
instantly, as expected. These rigs are far more resilient than one would
imagine.

BR Hairy
NOSPAM_oeieio(at)hotmail.com

On Feb 14, 8:26�am, "Hairy Lethal" (spellin
mistaik) wrote:
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)

About 2 years ago I was in a rather frivolous mood, brought about by a drop
of absolute vodka. I wondered just how certain things reacted when put in a
750 Watt microwave oven.

I first tried a new way of burning a CD. Amid sparks and a pyrotechnic
display that appealed to my sense of ****edness, it sort of got crazy-paved.
After about 20 seconds I had to switch off the microwave because of the
stench.

Then I turned to more "electronic" things. A Fujian MP3 player bit the dust
instantly. Basically there was one huge "wooooofff!", then the PCB set fire
to the plastic case after about 30 seconds.

Then I tried an old hamradio rig. It was an old Trio (Kenwood in the USA)
2200GX, crystal-controlled rig, with a rubber-duck antenna, and a battery
compartment that had not held batteries for several years. I put it in as it
was, but without the mic. Battery door open, rubber-ducky antenna on.

It sat there for about 15 seconds before anything happened, then the front
panel sparked a bit and caught fire. The front panel looked similar to the
CD, but a bit more melted-down, and the knobs had changed to a totally new
shape. But apart from that, the radio itself still worked fine after a 30
second 750W cook. It just looked more of a mess then it did originally.

Out of interest I tested it. I was expecting RF to get in the antenna and
coarse its way through the PCB, but no! The RF sensitivity was 1.25uV PD for
20dB sinad. Perhaps that was 10dB down, but it was still quite useable The
TX was still delivering 1.5 Watts.

I took off the case and tried again, and THAT killed it for sure. After only
10 seconds the PCB "whooffed", with loads of sparks and spitting.

But the point is that you cannot couple more power into a rig than that,
even with the cover on. The antenna was connected, and 750 W did not kill it
instantly, as expected. These rigs are far more resilient than one would
imagine.

Remember: All electronics works by means of smoke. If
the smoke leaks out, it won't work...

LA