Date: Mon, 5 Apr 2021 09:12:27 +0200 From: Peter Cornelius <pcc@gmx.net> To: freebsd-questions@freebsd.org Subject: Aw: Re: Wifi scanner for FreeBSD Message-ID: <trinity-bc777486-adab-486e-b7c6-dbafa025bab8-1617606747224@3c-app-gmx-bs57> In-Reply-To: <20210404133536.4fedf1e0@archlinux> References: <YGl3fCIhTnbowOVi@c720-r368166.fritz.box> <20210404185713.4d19ea73@ws1.wobblyboot.net> <YGmEVK8zs7caSFon@c720-r368166.fritz.box> <YGmO73%2BMLWl3wyD1@mithril.foucry.net> <20210404204512.3ba04756@ws1.wobblyboot.net> <20210404133536.4fedf1e0@archlinux>
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G'day, folks, =C2=A0 Regarding the first post, I would not mind to see such application in port= s myself though I think that the mobile apps suggest more than they hold=2E =C2=A0 Regarding 2=2E4 GHz WiFi, I have come to the conclusion that I will avoid = that band with WiFi wherever I can=2E I have the experience from my earlier= place in town where I was able to see the beacons of the order of 50 wlans= , that a single station not on one of the non-overlapping bands [1] causes = so much interference to all on one of the non-overlapping ones that there i= s no throughput at all for anyone=2E I don't know what kind of pot people h= ad when they invented that standard, but that's how it is=2E =C2=A0 When you use such 'free' channel (as in the image at the mail starting thi= s thread), all that happens is that you can't decode the others, and the ot= hers can't decode your emissions but you very effectively interfere with ea= ch other, making the entire spectrum unusable=2E And all the blue teeth and= other emissions on that band just add to that=2E =C2=A0 In short, if all stick to the non-overlapping channels (and do not bundle)= , one may get some throughput as the protocol can control the channel=2E If= one deviates, forget it=2E =C2=A0 Just my 2 cents=2E =C2=A0 Cheers, =C2=A0 Peter=2E =C2=A0 [1] https://en=2Ewikipedia=2Eorg/wiki/List_of_WLAN_channels =C2=A0 =C2=A0 Gesendet:=C2=A0Sonntag, 04=2E April 2021 um 13:35 Uhr Von:=C2=A0"Ralf Mardorf" <ralf-mardorf@riseup=2Enet> An:=C2=A0freebsd-questions@freebsd=2Eorg Betreff:=C2=A0Re: Wifi scanner for FreeBSD On Sun, 4 Apr 2021 20:45:12 +1000, matti k wrote: >https://imgur=2Ecom/a/J6HIGpZ It does show "available" networks, but not transmitting capacity=2E Due to digitalisation of elementary schools in Germany, enforced by the coronavirus pandemic, as somebody working for after school childcare, a teacher and I set up LTE wifi routers and iPads=2E That a network is displayed, doesn't mean that you get a reliable connection=2E The school has got 5 routers and IIRC 25 iPads + several other receivers (a digital board, smartphones and a TV)=2E I described my private network and mentioned that "I would be surprised to see it in about a 9 meter distance"=2E Actually it most likely is recognized by devices >=3D 9 meters away, but it's unlikely usable at this distance=2E The forums link provided by Matthias, see https://lists=2Efreebsd=2Eorg/pipermail/freebsd-questions/2021-April/29368= 2=2Ehtml[https://lists=2Efreebsd=2Eorg/pipermail/freebsd-questions/2021-Apr= il/293682=2Ehtml] mentions why it's a tricky subject=2E In school those iPads show powerful access to the LTE wifi routers, but often the closest routers isn't usable, while a less close router can be used, at least with a single iPad, dunno if it stands the traffic of all the iPads=2E The graphic provided by Matthias' Ubuntu based cellphone shows an amazing transmitting capacity spike=2E It could be important to actually get such information, not only for wifi=2E Depending on atmospheric condition, there could be e=2Eg=2E interferences between DVB-T transmitters=2E Too powerful signals could become a PITA for somebody who wants to watch television, OTOH amateur radio operators might welcome such atmospheric conditions ;)=2E Getting a list without reliable information about the power is quite useless=2E iPads for example provide a graphic showing 3 lines=2E Usually = 3 and 2 lines are for a good connection and even 1 line still could be reliable=2E At home 2 lines are ok for me, in school those lines mean absolutely nothing=2E You could get those lines, but the connection still could be fishy=2E _______________________________________________ freebsd-questions@freebsd=2Eorg mailing list https://lists=2Efreebsd=2Eorg/mailman/listinfo/freebsd-questions[https://l= ists=2Efreebsd=2Eorg/mailman/listinfo/freebsd-questions] To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd=2E= org"
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