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Hello,<br>
<br>
Do you like software defined radios? Do you like digital
communications? Me too!<br>
<br>
I took a Ubiquiti XR3 radio modem configured to operate in NV2 mode
with 20MHz bandwidth centered at 3.65GHz, and mixed it with a
3.68GHz local oscillator. The resulting unfiltered mess got fed to
my oscilloscope which digitized it into the attached file. The
sampling rate was 250MSa/s and the capture length was 32768
samples. The data in the file represents a single NV2 beacon
transmission, which lasts about 84us. The captured signal should be
centered at 30MHz with a 20MHz bandwidth. Having looked at the
signal in the frequency domain before digitizing it in the time
domain, I can tell you there are some unwanted mixing products here
along with the desired signal:<br>
<br>
<img alt="Main Signal" src="cid:part1.07050709.08020204@bartk.us"
height="480" width="640"><br>
The above image shows a marker (X) on the main signal at ~30MHz.<br>
<br>
<br>
<img alt="Product 1" src="cid:part2.09090403.02030202@bartk.us"
height="480" width="640"><br>
<br>
The above image shows a marker (X) at one mixing product at
~1.68GHz.<br>
<br>
<img alt="Product 2" src="cid:part3.05040208.00090609@bartk.us"
height="480" width="640"><br>
<br>
The above image shows a marker (X) at another mixing product at
~2.0GHz.<br>
<br>
Can you extract the data from this beacon frame? The outermost
encoding should be 20MHz 802.11a OFDM.<br>
<br>
--Bart<br>
<br>
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