[aprssig] RFID bigger coil
Wes Johnston, AI4PX
wes at ai4px.com
Thu Feb 25 12:35:47 CST 2010
Why not rectangular, say 4" x 30" to cover the threshold of a door?
On Thu, Feb 25, 2010 at 12:26, Robert Bruninga <bruninga at usna.edu> wrote:
> Biggest RFID Coil yet.
> Today, I doubled the size again to a 23" square coil and it
> works well. Resonance was not as peaked, but its vertical
> detection range was
> still about 12" and the outside-the-coil range was about 5"
> giving an overall
> HotSpot of nearly 33" across. THe advantage of this larger coil
> is that a moving
> tag is in the coil longer and therefore can be detected at a
> faster speed.
> Even throwing a card across the coil Frysbee style would always
> Shucks, in two more doublings of the size, it will be big enough
> (3' by 7') that might surround a door! I cannot imagine that it
> could possibly work because the field will be so weak... But who
> Bob, WB4APR
> aprssig mailing list
> aprssig at tapr.org
God help those who do not help themselves.
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