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