Don't forget that engineers find ways to make decent antennas many times smaller than actual wavelength. For example by folding or by creating resonant loops. Often this happens by accident. A small dc-dc converter running below 1MHz but where caps are placed slightly too far from the chip and connected by too long traces, so suddenly you see a very strong emission at 800 MHz for example.... With a cat it is very easy to make a resonant loop with the motor or battery wiring, fast switching transistors and (stray) capacitance. Cor.
On Nov 28, 2018 8:02 AM, "Lee Hart via EV" <[email protected]> wrote: Robert Bruninga via EV wrote: > Looks like EVs and hybrids get an exemption from RF emission limist of the > FCC’s part-15 limits. > > Looks like one could bulid a 1 MHz transmitter right in the middle of the > AM broadcast band and run it at 50,000 watts from an EV battery and not > violate part-15 limits! (exemption #1 and #8 and #10!) An EV can easily have a 50,000 watt controller. They generally switch at 15 KHz or so; not 1 MHz. But the harmonics can easily extend up into the broadcast band. If the wiring is done badly enough, it can produce a substantial amount of power in the AM broadcast band. The "saving grace" is that a car is too small to have a decent antenna at these frequencies. The wavelength at 1 MHz is 300 meters. This severely limits the range of the noise that an EV could radiate. -- Obsolete (Ob-so-LETE). Adjective. 1. Something that is simple, reliable, straightforward, readily available, easy to use, and affordable. 2. Not what the salesman wants you to buy. -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20181128/1a4d4dec/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
