Cool images. I’ve never tried this. I would have this afternoon, but our operations guys have the spectrum analyzer in another building. I’m a little surprised to see as nice a plot as you got in the second trace. Between near field effects and the potential to push the Rx amplifiers into a non-linear region I would have expected something more messy.
Do you know what the max signal strength was in the two traces? Also, do you know how to account for the increased duty cycle in the second one? I’m wondering if this is due to different iperf behavior or if it’s weirdness caused by proximity. I’ve been doing Wi-Fi for 15 years and still find myself guessing on a regular basis. From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Jason Cook Sent: Wednesday, March 08, 2017 6:08 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 2.4 GHz Interference Still learning my way through signatures but I have been caught out before with the anaylzer being too close to a wifi source Below shows this on channel 132, using iperf for a data burst in the first image the anaylzer is 1m away from a Mac Air, In the second it’s a few centimetres away from it. You can really see the impact on neighbouring channels at that distance (I think there’s even a bit in the 36-40 area) I now keep the anaylzer away from wifi devices as much as possible :) -- Jason Cook Technology Services The University of Adelaide, AUSTRALIA 5005 Ph : +61 8 8313 4800 From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Gray, Sean Sent: Thursday, 9 March 2017 7:26 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU <mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> Subject: Re: [WIRELESS-LAN] 2.4 GHz Interference Nope, the spectrum analyzer is going directly into a Surface Pro 2. From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Jake Snyder Sent: March-08-17 1:30 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU <mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> Subject: Re: [WIRELESS-LAN] 2.4 GHz Interference Are you using a USB 3.0 hub? On Mar 8, 2017, at 1:23 PM, Jason Heffner <jdh...@psu.edu <mailto:jdh...@psu.edu> > wrote: I’ve seen something similar when running some of the older Cisco controllers. If you ruled out everything else and are starting to look for devices causing interference I'd check out some of your wireless mic systems. We had some 800Mhz that we had to salvage that were causing harmonic distortion on 2.4GHZ similar to this on the lower channels. On Mar 8, 2017, at 2:32 PM, Gray, Sean <sean.gr...@uleth.ca <mailto:sean.gr...@uleth.ca> > wrote: Hi Everyone, I’ve been doing a little spectrum analysis around campus and I keep seeing the same interference signature in different buildings. I was wondering if anyone had seen anything like this before. It is typically visible for well over 10 minutes at a time and then it completely disappears. Thanks Sean Sean Gray | B.Sc (Hons) Voice, Collaboration & Wireless Network Analyst ITS, University of Lethbridge ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at <http://www.educause.edu/discuss> http://www.educause.edu/discuss. <Unknown Interference Source.PNG> ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss.
