On 07/02/2013 01:05 PM, Geoffrey S. Mendelson wrote:
On 7/2/2013 7:49 PM, Micha Feigin wrote:
Hi All,
I'm was wondering if anyone here can recommend a hardware / driver combo
for WIFI that allows access to the low level signal. I'm looking to do
some non-communication related research (uni stuff) that requires
sending custom signals over WIFI frequencies (to avoid FCC limitations),
and I was hoping that there is some existing hardware that I can hack at
the driver level instead of building complex hardware (which I have, but
getting a high enough accuracy starts getting pretty expensive).
I'm not looking to bypass power/frequency limitations, just to send
custom signals over one of the WIFI channels.
That would not be legal without an amateur radio or experimental
transmitter license.
You are not legally permitted to modify a WiFi device to transmit more
than 100mW EIRP, operate on the legal 2.4 and 5.8 gHz channels
allocated to WIFI and use any other modulation or data encoding.
You mention FCC limitations. They are different than Israeli ones as
far as EIRP, but basically the same about modification of devices. Of
course ISRAELI laws apply here and region 1 IARC rules.
If you are in an under FCC jurisdiction, that would be covered by
region 2 IARC rules and be aware that the FCC has a very active
enforcement division and would be glad to slap you with a $10,000 fine
for each violation they detect.
Sorry.
Geoff.
Thanks for the info.
I'm currently working in the states, probably should check Israeli/USA
law at some point. What I have now is this interesting setup which
implements narrow bandwidth radar at the 2.4GHz range. As far as I know
it is legal in the states (it uses readily available hardware as well)
http://www.glcharvat.com/Dr._Gregory_L._Charvat_Projects/Cantenna_Radar.html
It basically connects a signal generator to a voltage controlled
ocsilator with 200MHz bandwidth around 2.4GHz.
I was looking to expand on this idea in the direction of the work by
Dina Katabi from MIT CSAIL which require hacking the signal that the
radar sends
http://people.csail.mit.edu/fadel/wivi/
The trick is not to change spectrum or intensity, but play a bit with
the signal modulation within the regulated frequency range. Most of the
stuff could probably also be done within the legal / standard WIFI type
communication, but I need finer control over timing / encoding which
would probably be either very hard or impossible to achieve going
through the regular network stack.
I am also looking at UWB / XBAND but that is a completely different
discussion that involves people that are allowed to do it and very
custom (expensive) hardware.
Thanks
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