Suggestions for Hardware/driver WIFI combo that allows low level signal access

[E.S. Rosenberg]

>From all the previous talk I understand I may be way out of my league
but from managing campus Wifi networks I learned that Israel afaik
allows channels 1 through 13, while it limits channels 1-4 iirc to
indoor use only (god knows how the intended to enforce that one)

2013/7/2 Geoffrey S. Mendelson <geoffreymendelson at gmail.com>:
> On 7/2/2013 9:13 PM, Micha Feigin wrote:
>
>>
>> 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
>
>
>
> Dr. Charvat has an amateur radio license, callsign N8ZRY.
>
> As for the 2.4 gHz band being available for unlicensed use for unapproved
> devices I have no idea. I do know that it is NOT legal in Israel.
>
> There was a conflict between the IDF and Wifi and Bluetooth devices and the
> IDF was given a huge sum of money to buy new equipment to get off the short
> range bluetooth channels, and channels 4-8 of WIFI.
>
> Then Omri Sharon came back from vacation and showed his father some
> WIFI/Bluetooth device and by order of the Prime Minister, all Bluetooth and
> the EU Wifi channels were allowed. (1-12).
>
> However the power limit of 100 mW EIRP was strictly enforced and amateur
> radio operators lost their ability to use higher power.
>
> 5.8 gHz was allowed here April 1, 2012.
>
> Still one would have to be careful what you do, placing a USB WIFI dongle or
> a gain antenna of any sort inside a coffee can would raise the power beyond
> the 100mW EIRP limit.
>
> The famous Pringles can antenna is illegal both in the US and Israel. So are
> all of those $20 Yagi antennas on eBay, although if there is sufficient feed
> line loss they would be legal in the US.
>
> I think the best thing to do would be to contact Charvat directly and ask
> him for advice about what you can and cannot do.
>
> If you require an Amateur radio license, you can study for a technican class
> license in the US in a weekend (there often are "cram" classes) and take the
> test almost anywhere. If you are at MIT, I'm sure there is a radio club and
> people to help you.
>
> If I were you while you were at it, I would go at least as far as a General
> class license, the next step up. If you are an Israeli citizen, you can then
> get an Israeli license without taking any tests, as long as you can prove
> that you were studying in the US at the time.
>
> The MOC is legally required to accept your US license for conversion even if
> you flew in for the weekend, took the test and flew home, but it is a lot
> easier if you are living there when you take the test.
>
> Getting the equivalent of a General or Extra Class license in Israel is far
> more difficult than it is in the US.
>
>
>
>>
>>
>> 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.
>>
>
> That's very interesting. She uses standard WIFI hardware, channels and data
> streams which would make it legal.
>
> More likely, what you will have to do to use WIFI hardware is not only
> control the timing, but to figure out what bit patterns produce the signals
> that you want.
>
> Note that the legality of WIFI equipment and signals are based upon the
> transmitter, in the US it is legal to do almost anything with the receiver.
>
> You may want to look at the USB DVB-T dongles that are being used as
> software defined radios. I don't know of any that work as high as 2.4gHz,
> but there may be one by now.
>
>
>
>
>> 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.
>
>
> Way beyond this discussion.
>
>
> Geoff.
>
>
> --
> Geoffrey S. Mendelson,  N3OWJ/4X1GM/KBUH7245/KBUW5379
>
> _______________________________________________
> Linux-il mailing list
> Linux-il at cs.huji.ac.il
> http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il