On Mon, May 07, 2001 at 08:38:49PM -0700, David Honig wrote:
> At 01:08 PM 5/7/01 -0400, Trei, Peter wrote:
> >Making a car with electronic ignition stutter or stall
> >is *old* *news* to folk in the Ham Radio field. If they
> >really had to get within 5 feet, their car killer is really,
> >really feeble.
> >
> >Peter Trei
>
> This was probably with the first generations of electronic
> ignition (etc) systems, no? You don't hear of this any more.
>
A lot of this improvement came about because people began
installing transmit capable radios in their cars in considerable numbers
(beyond just a few eccentric hams) and discovered that the radios
sometimes made the car stall or sputter when they were keyed. So the
manufactuers came under pressure to clean up their act and RFI proof the
vehicle electronics before too many law suits resulted from irate
customers whose car stalled out dangerously in traffic due to RFI from a
nearby transmitter.
And such hardening is not that expensive if done by competant
EMI specialists as part of the initial design - thus it really wasn't
cost effective to leave it out - particularly if your vehicle line
grew a reputation of having such problems and fleet sales to customers
with radios installed dropped precipitously.
How effective typical vehicle hardening is against HPM pulses
in the gigahertz range at whopping power densities is less clear
as typical installed two way radio gear is HF to UHF at at most rather
modest power levels. There hasn't been a lot of need to protect vehicles
from very high power microwave energy which can pass through smaller holes
and be coupled into shorter length conductors - so there is likely
still considerable succeptablity if the flux density of the energy
is great enough.
>
--
Dave Emery N1PRE, [EMAIL PROTECTED] DIE Consulting, Weston, Mass.
PGP fingerprint = 2047/4D7B08D1 DE 6E E1 CC 1F 1D 96 E2 5D 27 BD B0 24 88 C3 18
