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I think any approach that aims antennas at an unsuspecting public is
going to run afoul of any number of laws, if not the unwanted
interest of some 3-letter agencies. We should also remember that
doing an RF scan from 160m through a few GHz is unlikely to happen
in real-time as a car zips past at freeway speeds. Nor do I think
that it would be of much benefit if we could.<br>
<br>
The issue here, I believe, is <i>not</i> one of raising the
planetary noise floor due to the fleet of cars moving from ICE to
EV. This is not a BPL type of issue. Cars are still, for the most
part, substantially enclosed metal boxes (i.e. Faraday cages),
containing whatever RF generated within. Rather, the question being
asked is related to conducted and short-distance radiated
interference within the car to the on-board systems. This includes
radios used for entertainment or vehicle communication and
monitoring (cellular voice and data, radar, etc.), and the cameras
and proximity sensors. The on-board systems need to have a clean
signal from all those devices in order to function properly. As a
result, while generating some RF across a variety of wavelengths is
inherent in any electronic system, designers are required to have
those fields limited in strength and contained in scope, regardless
of regulations, just to make everything and everybody happy.<br>
<br>
My car, for what it's worth, does include an AM radio, but its
antenna was improperly installed (it was left buried within the
dash, and out of reach for fixing). This means that the radio's AGC
is cranked all the way up, so it's overly sensitive to any
interference. It kind of works when sitting in the garage, picking
up the strong local stations without any interference. Out on the
road however, the lack of external reception, and the proximity to
internal systems, combine to make the AM band relatively useless.
Often all I hear on AM is the power system, especially during either
strong acceleration or regenerative braking. Other owners who have
a properly installed antenna fare a lot better, but there's not
enough exclusively-AM content to make me want to take the dash apart
to get to the antenna lead. <br>
<br>
VHF / UHF communication seems fine, by the way, both Ham and FM
broadcast. The FT-817 radio that I have installed is working fine
with the repeater network, with no apparent interference in either
direction (car to radio or radio to car). The radio does cover the
HF bands, but I haven't tried going there for lack of a suitable
antenna. I may try rigging something up, just for the experimental
data. But trying to work HF when QRP mobile is not much fun without
sunspots, so I'm not going to try for anything permanent.<br>
<br>
Also, a note that interference from ham transmitters to the car is
not an EV-specific thing. A club member recently mounted a mobile
rig in his ICE truck, and whenever he transmits on 2 meters, even on
low power, the car's dash display goes nuts. He's added ferrites,
but has yet to find a solution.<br>
<br>
Greg KO6TH<br>
<br>
<br>
<div class="moz-cite-prefix">Robert Bruninga wrote:<br>
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<div>How about this! Wrap a wire loop around an overpass and
hang some dipoles along the side an just listen to all the
cars going by. write down the noisey ones. It wount be as
good, but will bea fast sample...<br>
<br>
</div>
bob<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sun, Feb 24, 2019 at 3:18
AM Greg D <<a href="mailto:ko6th.greg@gmail.com"
moz-do-not-send="true">ko6th.greg@gmail.com</a>> wrote:<br>
</div>
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<div bgcolor="#FFFFFF"> It would certainly be an interesting
project, but a static "put it the Device Under Test on the
test stand and aim an antenna at it" wouldn't give an
accurate picture of a car's behavior. Just as an ICE's
spark-gap transmitters, as well as alternators and the
various other electronic systems change their
characteristics with RPM and engine / accessory load, so
do EVs, and with an added dimension when they go into
regen. You can't measure this stuff with a parking lot
test. <br>
<br>
More accurate, I think, would be to put the antenna and
test equipment in/on the car, and drive it on a prescribed
course, including acceleration and deceleration events.
This could be done on an actual track or a dynamometer.<br>
<br>
Greg<br>
<br>
<br>
<br>
<div class="gmail-m_8501779102672699366moz-cite-prefix">Robert
Bruninga wrote:<br>
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<div dir="ltr">
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<div>We really do need to get a handle on this.<br>
<br>
</div>
Set up a standardized test coil in the Parking lot
of ARRL and have every visitor park on it for a
test. Tehn publish the stats. Good project!<br>
<br>
</div>
Bob<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sat, Feb 23,
2019 at 2:42 PM Ev Tupis via aprssig <<a
href="mailto:aprssig@lists.tapr.org"
target="_blank" moz-do-not-send="true">aprssig@lists.tapr.org</a>>
wrote:<br>
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style="font-family:courier
new,courier,monaco,monospace,sans-serif;font-size:16px">
<div>I guess that I can assume that QRM is as
prevalent as it always has been. I was
hoping that the state of the art would have
progressed by now...but with an FCC waiver
to Part 15 applied there is little
incentive.<br>
</div>
<div><br>
</div>
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<div
id="gmail-m_8501779102672699366gmail-m_-5054369157429144021ydp751f7eafyahoo_quoted_1060200602"
class="gmail-m_8501779102672699366gmail-m_-5054369157429144021ydp751f7eafyahoo_quoted">
<div>
<div> On Friday, February 22, 2019, 10:19:21
AM EST, Ev Tupis via aprssig <<a
href="mailto:aprssig@lists.tapr.org"
target="_blank" moz-do-not-send="true">aprssig@lists.tapr.org</a>>
wrote: </div>
<div><br>
</div>
<div><br>
</div>
<div>
<div
id="gmail-m_8501779102672699366gmail-m_-5054369157429144021ydp751f7eafyiv2526290539">
<div>
<div>A number of years have passed
since I asked this, and I find
myself in the market for another
car, so I'll ask again.</div>
<div><br>
</div>
<div>Is there a recommendation (from
personal experience) in regard to a
hybrid car that presents minimal QRM
to HF operation while in-motion?</div>
<div><br>
</div>
<div>Ev, W2EV</div>
<div><br>
</div>
</div>
</div>
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