Re: [EVDL] EV emission limits

[Cor van de Water via EV]

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"  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

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Re: [EVDL] EV emission limits

[Lee Hart via EV]

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
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[EVDL] EV emission limits

[Robert Bruninga via EV]

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!)



Bob, WB4APR



*From:*  Ev Tupis via aprssig
*Subject:* Re: [aprssig] OT: Part 15 / Electric Vehicles



Electric Vehicles and Hybrids are exempt from Part 15 compliance.  I'm
trying to understand the basis for the RFI issues at-play.  See the list of
top ten part-15 exemptions:



https://emcfastpass.com/could-your-product-be-exempt-from-emc-testing-altogether/
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