Transmit Rate/MCS Index Reports

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    I ran a scan (version 2.4.585) today of a site with approximately 6000 square feet of space and a pair of 802.11n dual band APs. Following the scan, I find that the wireless transmit rate report shows 145 Mbps across the board for both 2.4 GHz and 5 GHz. While this is useful from a theory standpoint, I could also see while scanning that my computer’s transmit rate fluctuated up and down with position in the facility, giving me anywhere from a 26 Mbps rate all the way up to 145 Mbps.

    Would there be any way to visualize the rate that my machine negotiated with the APs? This seems like it could be more useful to have than the maximum theoretical transmit rate, given that the theoretical rate can be derived from knowledge of the equipment.

    best regards,


    Would you rather be looking into Download Speed visualization? The transmit rate is a value between your computer and the router, while it seems to me you are looking for the other one. I might be wrong. Let me know.



    Well a couple of comments on that.

    1. In theory, I might be more interested in the MCS index and the transmit at which the testing machine is connected to the SSID at a given point on the floor plan. I feel like the actual negotiated transmit rate might be a more useful thing to display on a visualization for easy consumption. Otherwise I just end up with a map covered with “145”, which tells me the theoretical max but doesn’t tell me much about what my machine was actually registering.

    2. In my case, I was attempting to run the iperf3 performance testing from Netspot, and every time my machine would start a Netspot iperf3 test while taking a sample, I’d lose my IPv4 DHCP lease on the network and would not be able to re-establish a connection via wireless without disabling and re-enabling the wireless interface in my machine. I’m going to run that test on a different network this afternoon and see if it repeats, but I would note that when I used my manually-installed copy of iperf3, the testing ran without issues.



    Okay, so I followed up with some testing at another site that I’ve walked through before. I downloaded and compiled iperf3 on an available testing machine running OS X 10.10.1 and assigned it a static IP address. When attempting to run a scan that includes iPerf testing, I notice a couple of things:

    1. Every time NetSpot goes to start a performance test it asks for permission to ask the network (named by SSID) in the keychain. Even if I click “Always Allow”, NetSpot asks for every sample point. This is incredibly irritating.

    2. After allowing access to the Keychain Item in question, NetSpot gives me an error that “iperf3 TCP upload speed test failed: $CompanySSIDName”. If I try again, it eventually stops erring out and continues.

    The behavior described in 1&2 above occurs for every sample point.

    It occurs to me that the test I described in an earlier post was done at a site with a RADIUS server that has an expired certificate. Notably, the behavior with Keychain never occurred at the other site, making me wonder if there’s some kind of authentication issue happening in NetSpot. Notably, at the first site described, running a vanilla iperf3 test from my machine worked just fine; it’s only in NetSpot that I’m getting kicked out.



    So I’ve been intending to do a full rebuild of my machine as part of upgrading to Yosemite, and I finally did that over the weekend, with the following results:

    1. A freshly-installed copy of NetSpot 2.4.585 running under 10.10.2 did not ask for access to the keychain on every sample point as I described above.

    2. In addition, the behavior that I described above in which NetSpot displays the maximum transmit rate available on the network no longer occurs. In the test scan I performed today, the reporting shows variable transmit rates which I interpret to be the achievable data rate at each location.

    I would be happy to share the .netspd file with you if you would like to examine it.


    It would be awesome to have a look at the survey project. Please email it to and reference this topic. Anyway, it seems that the OS X upgrade worked out really well for you, correct?



    Will do. Thanks!

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