[RFI] Attention 20m fans: Something New for Your Listening Pleasure - Maybe

[michael.findley at ni.com]

Medical equipment falls under the EMC directive enforced in March 1997. The
spec is EN60601-1-2 for those with more money than cents ;)
The spec tests for Emissions (10 meters usually used) (the old standard
required 30 meter test distance. The limits are from 30MHz to 230MHz @
40dBuV/meter and from 230MHz to 1 GHz the limits are 47dBuV/meter.
The spec also requires limits on conducted emissions on the power lines
from 150kHz to 30MHz.
Depending on how it is used the immunity tests range from 3Vrms/meter to
10Vrms/meter for radiated immunity.
The equipment also is required to pass surge tests and fast transient
tests.
Conducted RF capacitively coupled to all power lines at 3Vrms carrier AM
modulated @ 80% (levels for 150 ohm load).
Well enough Government crap for me I am done.
(Embedded image moved to file: pic15890.gif)


                                                                                                                                       
                      "Cortland                                                                                                        
                      Richmond"                To:       rfi at contesting.com, dgsvetan at rockwellcollins.com                              
                      <ka5s at earthlink.n        cc:                                                                                     
                      et>                      Subject:  RE: [RFI] Attention 20m fans: Something New for Your Listening    Pleasure -  
                      Sent by:                  Maybe                                                                                  
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                      08/26/2003 09:10                                                                                                 
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                      ka5s                                                                                                             
                                                                                                                                       
                                                                                                                                       




Interesting post. However, this appears to be little threat.  Power and
signal coupling by induction falls off very rapidly with distance. Note
that even with a "booster antenna" (probably a larger area loop on the
sensor) max operating range is 30 mm -- under 1¼ inches. And at 26.48 KB,
bandwidth will not be all that wide. One might be able to pick it up with a
portable SW receiver for a few feet.


Cortland

Dale, WA9ENA wrote:
> Other than the justifiable flood of BPL messages of late, I do recall
some
> recent posts possibly involving medical equipment causing 20m
interference.
> As was indicated at that time, there is a designated ISM (Industrial,
> Scientific, Medical) band at 13.56 MHz.  If that equipment is well
designed



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