RE: Noise level inside an fully anechoic chamber

[owner-emc-p...@majordomo.ieee.org]

Don't forget that you can minimize ambient in the measured system if there is
a control room to the SAC setup. The analyzer itself will allow signals to
invade the measurement.
 

Michael Sundstrom 
 NOKIA 
  TCC Dallas / EMC 
   ofc: (972) 374-1462 
    cell: (817) 917-5021 
     amateur call: KB5UKT 


From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of ext 
Sent: 15 March, 2004 09:21
To: kbalasubraman...@scmmicro.co.in; emc-p...@majordomo.ieee.org
Subject: RE: Noise level inside an fully anechoic chamber


As there are high levels everywhere, please check the noise floor first.
Remove antenna, or replace with 50 ohm terminator. Measure like you would have
the antenna there. The result is the noise floor with the settings you use.
 
Ari


From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of ext
drcuthb...@micron.com
Sent: 15 March, 2004 17:10
To: kbalasubraman...@scmmicro.co.in; emc-p...@majordomo.ieee.org
Cc: ken.ja...@emccompliance.com; owner-emc-p...@majordomo.ieee.org;
ri...@sdd.hp.com; vef00...@nifty.ne.jp
Subject: RE: Noise level inside an fully anechoic chamber


Wow,
these are very high levels. There is certainly a  problem. I would first
suspect the cabling into the chamber- is is bonded at a bulkhead? Also, if the
receiver/spectrum analyzer is in the chamber you will see lots of stuff.
 
  Dave Cuthbert
  Micron Technology

From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of
kbalasubraman...@scmmicro.co.in
Sent: Saturday, March 13, 2004 8:15 PM
To: emc-p...@majordomo.ieee.org
Cc: Ken Javor; owner-emc-p...@majordomo.ieee.org; ri...@sdd.hp.com; T.Sato
Subject: Noise level inside an fully anechoic chamber



Dear Experts,         
        I am conducting pre-scans in a 3-meter fully anechoic chamber. It is
noticed that even when no equipment is present inside the chamber the field
strength is about 20 to 25 db micro volts per meter in the frequency range 30
to 350 MHz, about 27 to 32 db micro volts per meter in the frequency range 350
to 600 MHz and about 33 to 39 db micro volts per meter in the frequency range
600 to 1000 MHz. What is the level of ambient noise permissible in fully
anechoic chambers? Which section of FCC deals with measurement site
qualifications? 

Sincerely

K.Balasubramanian
Sr.Engineer, Hardware.