Hi Ralph, I did this 2 and half years ago and I basically followed the directions in pages 60-61 of the ETSI document linked by Marcus to generate the signals.
By watching the channel on which the WiFi card was operating, I generated the signal at the right frequency and I could see the card changing frequencies. I could then access some log files that detailed why the frequency change happened (In this case it was saying that it had detected a radar with a given Pulse Repetition Frequency and gave some details about the detected signal). I believe I was using the ath5k drivers (see madwifi-project). Regards, Jawad 2016-01-08 22:56 GMT+01:00 Marcus Müller <marcus.muel...@ettus.com>: > Hi Ralph, > > hm; depends, I think. > > So, there's two things: > If you're referring to a channel switch announcement, that can be part > of a management frame [1]. But I think it can also be part of a beacon > frame. Or a probe response frame. > Luckily, 802.11 is not confusing the least. > Blind guess is that you should look into airprobe-ng's "aireplay" > program and see whether it can synthesize such a frame. Basically, you > should be able to forge at least beacon frames, which might be helpful > as soon as you deauthenticated a station; a very common attack. > > More likely, even, is that you're talking about mimicking a fake radar. > I guess the appropriate way to do that is probably sending something > that looks sufficiently close enough to a chirp to the OFDM demod, I think. > I'm too lazy to read this myself :D, so go and read 5.3.8.1 and > following of ETSI EN 301 893 [2], and refer to a trustworthy free and > open WiFi card driver (hint hint: atheros 9k, dfs_pattern_detector.c). > > Best regards, > Marcus > > [1] > > https://mentor.ieee.org/802.11/dcn/10/11-10-0097-06-00ae-management-frame-analysis.xls > [2] > > https://www.etsi.org/deliver/etsi_en/301800_301899/301893/01.05.01_60/en_301893v010501p.pdf > > On 08.01.2016 21:47, Ralph A. Schmid, dk5ras wrote: > > Hi, > > > > Does anybody know how a signal must look to trigger a 5 GHz WLAN for a > > frequency change? I intend testing this feature by transmitting a > radar-like > > signal with gnuradio, but for this I should know how this detection > works, > > how such a signal does look :) > > > > Ralph. > > > > > > _______________________________________________ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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