--- On Wed, 14 May 1997 14:17:57 +0100 "Vi Van (MEPCD)" <[email protected]>
wrote:
>Dear All,
>
>Radiated emission can be performed either on an open area test site or a
>semi-anechoic chamber.
>
>Many test house do the initial scan in the anechoic chamber to find
>worst frequencies before performing it on an OATS.
>
>The initial scan in the 3m Anechoic chamber shows that there are
>serveral frequencies may be above the limit.
>
>So EUT were taken out to test on an OATS.
>
>What I would like to know is if you are performing the test on an OATS,
>unfortunately the abient level for those frequency are very high and it
>is above your EUT level. What would you do?
>
>Would you?
>
>1. Ignore that frequency.
>
>2. Move the EUT to 3m and hope the EUT level is above the abient level.
>What happened if the EUT is too large to be regarded as "electrical
>small".
>
>2. Use the 3m semi Anechoic Chambers results -10dB, if this means fail
>then modify the EUT in the chamber until it passes.
>
>4. Use different OATS.
>
>Are they any guideline from the Trade Industry regarding this situation?
>
>Any comments are very welcome.
>
>Best Regards
>
>Vi Van
>EMC engineer
>Mitsubishi PC.
>>
>
-----------------End of Original Message-----------------
Vi:
One most honorable tradition in open field emission testing is to wait
until about 0200 on a Sunday. Most other people have enough sense to be asleep
then, and you just might get a window of opportunity to view that emission in a
much quieter ambient.
Short of trying a different test site, you may be able to identify and
locate the offending emitter. Some negotiation may yield a mutually agreeable
time when the emitter could be shut down for a short time.
--------------------------
Ed Price
[email protected]
Electromagnetic Compatibility Lab
Cubic Defense Systems
San Diego, CA. USA
List-Post: [email protected]
Date: 5/14/97
Time: 10:56:05 AM
--------------------------
