Typically conducted emissions are measured using a clamp on coupler and are
lower in frequency. In the DO-160 I've been involved with, testing and the
range for conducted emissions is typically 150khz to 150mhz.
Radiated emissions are measured with an antenna and receiver placed a specific
distance from the device and are typically 100mhz and up.
In the case where there is an overlap, say you have a conducted problem at 125
mhz as well as a radiated problem at the same freq, elimininating the conducted
source will usually fix the radiated issue.
We keep conducted emissions low to prevent noise from being coupled into other
gear on the aircraft via the power / RTN lines. We limit radiated emissions to
minimize interference to other gear via the air waves
From: Tony <email@example.com>
To: Rfi List <firstname.lastname@example.org>
Sent: Wed, Dec 18, 2019 4:04 am
Subject: [RFI] Question: Conducted vs. Radiated Emissions
I have a question regarding FCC limits on conducted emissions that
relates to radiated emissions.
If a solar panel system produces electromagnetic energy that finds its
way onto the mains and then onto the power lines which then radiates
over the air, that device would be subject to the limits imposed on
If the same solar panel system radiates the same energy over the air
through the cables that make up the system without reaching the mains,
FCC regulations would not apply since there are no limits on radiated
In a situation where both cases produced the same high level of RFI,
what course of action would the FCC take? Would they simply dismiss the
radiated emissions case and enforce the conductive case simply because
of route the energy took?
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