[RFI] Question: Conducted vs. Radiated Emissions

[Thomas Hoyer]

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
TomW3TA



-----Original Message-----
From: Tony <dxdx at optonline.net>
To: Rfi List <rfi at contesting.com>
Sent: Wed, Dec 18, 2019 4:04 am
Subject: [RFI] Question: Conducted vs. Radiated Emissions

All:

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 
conducted emissions.

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 
emissions.

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?

Tony -K2MO

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