Mac,
The biggest effect I've seen was due to the fire retardant in the old cones
absorbing moisture and subsequent dielectric changes. We had to put in a
humidity controller to keep the chamber and cones at the same RH all the time
to get consistant measurements.
Bill
Barron, Manny
In message 20060113213741.90815.qm...@web36805.mail.mud.yahoo.com,
dated Fri, 13 Jan 2006, Hans htm...@yahoo.com writes
There are formulae for calculating the ERP/EIRP power loss due to
moisture content in the air. Typically used when calculating point to
point microwave links over several
There are formulae for calculating the ERP/EIRP power
loss due to moisture content in the air. Typically
used when calculating point to point microwave links
over several miles and especially over a water body.
It seems the loss is near neglible within a 10m
distance.
Hans
Best Regards
Hans
, January 13, 2006 11:42 AM
To: Elliott Mac-FME001; emc-p...@ieee.org
Subject: RE: Humidity and Radiated Emissions Tests
Interesting question!
Water is a dielectric with absorptive properties that are frequency dependant.
The most well-known peak absorption is the microwave oven 2.4GHz frequency
Is the site near the ocean? Salt plays havoc in moist air.
Also, if in a dirty environment where particulates are high it could affect
readings.
These issues however should be able to be accounted for in your uncertainty
budget.
Dennis Ward
Evaluation Engineer
American TCB
Certification
In message
54ffbe24c443bc45b8deb804650d2d2ba3a...@ct11exm64.ds.mot.com, dated
Fri, 13 Jan 2006, Elliott Mac-FME001 fme...@motorola.com writes
What is your opinion - does relative humidity have an effect on
radiated emissions testing [as long as there is no condensation on the
EUT]?
The phases
Interesting question!
Water is a dielectric with absorptive properties that are frequency dependant.
The most well-known peak absorption is the microwave oven 2.4GHz frequency. If
you are having EMI issues in this frequency area, you may want to wait for a
high-humidity day. 8-)
In
Hello Mac,
I don't know the actual physical effect,
but there is a requirement in the ANSI C63.4, para 6.1.9.
Sincerely,
Manny Barron, EMC Engineer
Northrop Grumman Mission Systems
Intelligence Systems Division
Electromagnetic Systems Laboratory
6377 San Ignacio Avenue
San Jose, California
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