|
[si-list]
||
[Date Prev]
[08-2001 Date Index]
[Date Next]
||
[Thread Prev]
[08-2001 Thread Index]
[Thread Next]
[SI-LIST] Re: Gigabit fiber transceivers, EMI, trace lengths, and... antennas.
- From: "Doug McKean" <dmckean@xxxxxxxxxxxxxxx>
- To: <si-list@xxxxxxxxxxxxx>
- Date: Thu, 9 Aug 2001 14:46:27 -0700
"Kolstad, Joel (EIP)" wrote:
>
> So, we have a fix, but I'm curious -- how does a 318.75MHz
> signal radiate from a hole in the rear bracket that's ~.4"x.3" wide?
You'd be surprised at how little energy is needed to
violate emissions testing levels. I did a little informal
experiment with various length stub antennas starting
at 1 inch on up to 6 inches and found high levels of
emissions from 30MHz to 1GHz with something like
a -20dB/decade rolloff. Not bad for a piece of wire
1 inch long.
And it most likely isn't the hole that's radiating. It's
probably the bracket by way of a slot effect. Slots
are electrical duals of wires, but their directivity is
roughly 10 times that of a simple wire.
- Doug McKean
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
http://www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
|
|
