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RE: [RFI] Attention 20m fans: Something New for Your ListeningPleasure -

To: ka5s@earthlink.net
Subject: RE: [RFI] Attention 20m fans: Something New for Your ListeningPleasure - Maybe
From: <dgsvetan@rockwellcollins.com>
Date: Tue, 26 Aug 2003 09:18:30 -0500
List-post: <mailto:rfi@contesting.com>

Glad you found it interesting.

I agree about not hearing the chips themselves - their range is much too
limited.  My point was the "exciters" used to write and read with these
chips.  THose are the power drivers.  After all, the coupled 13.56 MHz
energy into the chip must not only give it commands and write or read data,
but it also provides the operating power for the chip.  Any guesses on the
efficiency of that on-chip antenna at 13.56 MHz?

Yes, overall, I do not expect much threat.  However, I could see possible
problems for hams who use 20m and who live near retail sales locations
where the RF exciters will be placed to power up and read the tags.  If
that equipment is well-designed, then probably no issue.  However, if it
has "loose" specs or is not properly adjusted, then the potential for
interference exists.

73, Dale

                      Richmond"                To:       rfi@contesting.com, 
                      <ka5s@earthlink.n        cc:                              
                      et>                      Subject:  RE: [RFI] Attention 
20m fans: Something New for Your Listening Pleasure -     
                      08/26/2003 09:10                                          
                      Please respond to                                         

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.


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

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