Tuesday, September 3, 2019

False Expectations and Confusion with 802.11ax

There is a lot of confusion and false expectations regarding 802.11ax flavored Wi-Fi these days.  Articles that compare 802.11ax to switches sets a dangerous president and leads to confusion in the marketplace as to what 802.11ax is and what it can do.

Take this article as an example:

https://www.arubanetworks.com/assets/wp/WP_Multi-User-802.11ax.pdf

"802.11AX TO THE RESCUE"

"With 802.11ax, MU-MIMO has been enhanced to support uplink traffic, from the client to the AP, and will support up to eight clients at a time (802.11ac allowed for eight, but no one implemented more than four). This doubles the number of devices to which an AP can talk, and because traffic is supported in both directions, clients can transmit simultaneously back to the AP, similar to how an eight-port switch would work on a wired network."

Here is where the confusion lies:  A client cannot transmit simultaneously back to the AP while receiving a frame from the AP - meaning, full duplex.  That is not in any 802.11ax draft amendment.  If this was possible, this is still not similar to how an eight port switch works.  Ethernet switching allows clients to send traffic on the wire whenever they want because the connection to the network is not a shared medium.  Wi-Fi is an unbounded, shared medium in unlicensed frequency band.

 

"Wider channels can support even more sub-channels. An 80 MHz wide channel can support up to 37 clients at a time. Like MU-MIMO, OFDMA supports downlink traffic, from the AP to the clients, and uplink traffic, from the clients to the AP. If MU-MIMO is a high speed 8-port switch, then OFDMA is a lower speed 37 port switch."

 

Here is where the confusion lies:  A client cannot transmit simultaneously back to the AP while receiving a frame from the AP - meaning, full duplex.  That is not in any 802.11ax draft amendment.  If this was possible, this is still not similar to how a thirty seven port switch works.  Ethernet switching allows clients to send traffic on the wire whenever they want because the connection to the network is not a shared medium.  Wi-Fi is an unbounded, shared medium in unlicensed frequency band.  Also, an 80 MHz channel is simply the aggregation of four 20 MHz channels into one channel.   If there are twenty 20 MHz channels and five 80 MHz channels, they are using the same spectrum.  Currently, date frames are transmitted consecutively using the entire channel. For example, if a client is connected to a 20 MHz wide channel and sends data, the entire channel is taken up and then the AP and clients take turns, one at a time, sending data on the channel.  This will continue until all of the legacy 20 MHz client devices (802.11a, 802.11n, 802.11ac) are removed from the network.  This includes the WLAN's access points and client devices, and also neighboring WLANs that are within earshot of the 802.11ax network.  It is not uncommon to do a survey of an existing building and see 700+ neighboring access points.  This number does not include the client devices on those 700+ access points.

 

"This has led to designs with more lower-bandwidth channels to reduce interference. 40 MHz-wide channels are the norm in office deployments, with 20 MHz wide channels used in high density offices or in environments where there are fewer channels available because of noisy RF neighborhoods.  BSS coloring allows the network to assign a “color” tag to a channel and reduce the threshold for interference.  Network performance is improved because APs on the same channel can be closer together and still transmit at the same time as long as they are different colors. Because we can have fewer channels, it may also be possible for organizations to use wider channels, such as 80Mhz channels in some or all of their network." 

 

Here is where the confusion lies:  The previous paragraph states "This has led to designs with more lower-bandwidth channels to reduce interference. 40 MHz-wide channels are the norm in office deployments, with 20 MHz wide channels used in high density offices or in environments where there are fewer channels available because of noisy RF neighborhoods."  Enterprise Wi-Fi networks should usually be set to 20 MHz channel plans because of the density of access points due to the data/voice/RTLS/higher density design and the noisy RF neighborhoods of the facilities.  80 Mhz channels are not usually used in Enterprise environments, therefore that does not apply.

"If MU-MIMO and OFDMA make the wireless network behave more like a switched environment, then BSS coloring adds switching capacity to the network."

 

There is a lot of confusion regarding 802.11ax - especially with this subject.  MU-MIMO and OFDMA does not make the wireless network behave like a switched environment, therefore that statement is not accurate.  Switching uses CSMA/CD, (carrier sense multiple access with collision detection) and Wi-Fi uses CSMA/CA, which is carrier sense multiple access with collision avoidance.  The two are massively different than each other - CD can sense a collision, which usually does not happen now that we plug hosts into switches and the collision domain exists between the host and the switch.  Collision Avoidance is still the same.  The medium is still in a shared spectrum with all those cordless phones, video cameras neighboring networks and everything else I have forgotten to mention.  None of those things exist in the copper cabling between a host and a switch with CSMA/CD.  There is no way to "detect" a collision with Collision Avoidance - if the station did not receive an acknowledgement for the unicast packet it transmitted, it will retransmit the packet, assuming the receiver did not receive it.

 

"With MU-MIMO, an AP can behave like a high speed, 600 Mbps per client 8 port switch, great for large file transfers and high-performance clients. OFDMA allows an AP to behave like a lower speed, ~25 Mbps per client 37 port switch, good for normal network use and voice and video streaming.  An AP can switch back and forth between these two modes every transmit cycle as the needs of the clients change. We don’t have a dedicated connection for each device like you would in a wired network, but we are able to adjust the amount of network capacity allocated to each device depending on need, which is something wired networking can’t do. Although we don’t have a full-duplex switch, we effectively have time-division duplexing that emulates full duplex over shared/half-duplex mediums. In the end, we gain a lot of the benefits of switching and wireless and 802.11ax is likely to be the point where we think of Wi-Fi less like an old bridged network and more like a high-speed modern switched network."

 

Even more confusion:  An AP cannot behave like a high speed, 600 Mbps per client 8 port switch.  Switches use CSMA/CD, and 802.11ax will use CSMA/CA.  A switch is full duplex - meaning simultaneous transmit and receive to a client, as long as the port negotiates properly.  802.11ax is not full duplex.  Switches commonly use gigabit speeds on every host port, and 802.11ax does not equal an eight port (or 37 port) 1000 Mbps full duplex (no collision domain) Ethernet switch.  We do not "gain a lot of the benefits of switching" with 802.11ax.  We do not have collision detection, we still share the frequency/channel with all the other wireless devices on that frequency, and we do not have full duplex (simultaneous) transmit and receive to a client.

 

 

 

Wednesday, August 21, 2019

NetAlly's AirCheck G2 gets a facelift with version 4.0 firmware

 

NetAlly's (formerly NetScout) AirCheck G2 gets a facelift with version 4.0 firmware

 

We learned at Mobility Field Day 4 that NetAlly has been working on version 4.0 of the AirCheck G2 firmware, so here is a quick post on how I upgraded mine.  I decided to take the “offline” approach because sometimes you don’t have an Internet connection to get the job done.  I know that seems hard to believe, but I once worked at a place where no USB anything, no phones, no cameras, no nothing was allowed through the checkpoint.

 

So here goes:

 

                    Download the AirCheck G2 Manager v3.1.485 software from the support page at NetAlly.com (http://www.netally.com/support/downloads), and install it on a PC. (I installed on Windows without issue)

                    Note: When you get to the website, scroll down until you see this, and select the Aircheck G2.

                     

                   

                    When AirCheck G2 is selected, these files will show up:  I downloaded all of them into the same folder.

                     

                   

                     

                    For whatever reason, I could not download the MAC Prefix File, so I scraped it into a Notepad and saved it as a .txt file.

 

                    Download AirCheck G2 v4.0 firmware (https://www.netally.com/support/), and save it also.  I put mine in the same folder.  The firmware is the ACFX file.

                     

                   

 

                     

                    Launch the newly installed AirCheck G2 Manager v3.1.485.

                     

                    Attach your AirCheck G2 unit to your computer using the micro USB cable.

 

                    In AirCheck G2 Manager v3.1.485 go to the Device Info screen, select the “Update AirCheck G2 Firmware…” button.

 

                   

 

                    Follow the prompts to upgrade your unit to the v4.0 firmware. The unit reboots and takes several minutes, so do not do this step if you don’t have time to do it.

 

                    Next, I uploaded the vendor OUI text file I created.  This was extremely simple.

 

                   

 

                     

                     

Now I am going to see if everything “added” to the firmware works as described:

 

1. 802.11ax Visibility: I have an 802.11ax client on the network and I will see if the AirCheck G2 sees it: (and it does)

How did I take that screenshot from my AirCheck G2?  This is on page 104 of the manual: (I didn’t know how to do it either)

I used the AirCheck G2 Manager to get the screenshot since I am using the non-link-live way of upgrading my AirCheck G2 today.  I simply transferred them to my PC – it was very painless to accomplish.

 

 

                    Identify 802.11ax Networks – Sadly, I do not have an 802.11ax access point to verify this – however I could clearly see my 802.11ax laptop was identified.

                     

2. Combined Utilization View: This option allows the combination of 802.11 utilization and non-802.11 utilization into a single total utilization graph that will include 802.11a/b/g/n/ac/ax traffic and non-802.11 traffic.

            Here is how to get there to make the change: (I made the change back and forth but did not have an environment to see any results)

           

 

3. iPerf Test Results Uploaded to Link-Live:

 

In order to get to the iPerf test function, you first need to connect the G2 to an AP or Network, run a test and when complete, look at the bottom of the screen for “Tests”.

 

If you use the NetAlly Test accessory, it should show up in the list.  If you don’t know what I am referring to, look at this link: https://www.netally.com/products/testaccessory/

I use the WLANPi iPerf server (available here: http://www.wlanpi.com/ and I had to enter in the IP address of my device.  I ran the iPerf test just fine, and it did upload to Link-Live, however it did not end up in my inbox like all the other tests I ran.  I am not sure if this is because I am using the wlanpi instead of the NetAlly device.

 

Overall, the new version 4.0 does what it says it does.  I would like to see the iPerf end up in my inbox automagically in a future release, or possibly some documentation on how to make it happen.

 

 

 

Monday, July 15, 2019

My Ekahau Sidekick offsets

 

Ekahau users that use the Sidekick have probably discovered that the Sidekick “hears” better than other devices?  How much better, you ask?

 

Since I do a lot of validation surveys, I decided to do a comparison between four devices.  The 5 GHz Vocera “communicator” badge that is deployed quite a bit in Healthcare, the “Netscout” AirCheck G2 (in parenthesis because I heard that Netscout doesn’t own that product anymore though the name is still on the box), my handy dandy Samsung Galaxy S7 Edge (that just so happens to be the platform used by a company that deploys Google Glasses), and my trusty Sidekick.

 

My main concern was “what is my Vocera offset” for doing surveys to determine if the WLAN is voice quality.  So, we took two Vocera badges and put them side by side, and during our testing, averaged the two into one measurement.  I must say this was easy, since the Vocera badges usually agreed with each other within one dB.

 

We tried not to skew the results in any way.  We didn’t look at previous results during the testing.  We didn’t look at other results and compare while testing.  We simply walked through a medical office building and randomly stopped in areas and took readings.  This was intentional, as we didn’t want to add “intelligence” into the equation.  We even took measurements in the basement, where coverage was minimal.  When complete, we added them up and divided by the number of readings.  Very simple.

 

Sometimes we throw out “highs and lows”, and average the rest.

 

When using the data we gathered, not tossing out the highs and lows, our offsets came out like this:

 

Vocera                 -11.66 db

AirCheck G2        -13.44 dB

Galaxy S7 Edge   -13.66 dB

 

When using the data we gathered, tossing out one high and one low, our offsets came out like this:

 

Vocera                 -12.00 db

AirCheck G2        -13.14 dB

Galaxy S7 Edge   -13.28 dB

 

Moving forward, I feel as though a 12 dB offset can be used in my environment when looking at the WLAN surveys with Vocera communicators in mind.

 

Actual readings walking a floor of a medical office building:

 

Ch:         Vocera  G2          S7           Sidekick

 

44           -46         -49         -55         -40

 

44           -77         -75         -76         -64

 

64           -61         -56         -56         -46

 

56           -69         -74         -76         -55

 

52           -68         -69         -74         -59

 

36           -73         -74         -75         -62

 

161        -68         -66         -60         -53

 

36           -70         -79         -76         -59

 

48           -78         -84         -90         -67        

 

 

dB Difference between each device and SK

 

Ch:         Vocera  G2          S7           Sidekick (original dB reading)

 

44           6             9             15           -40

 

44           13           11           12           -64

 

64           15           10           10           -46

 

56           14           19           11           -55

 

52           9             10           15           -59

 

36           11           12           13           -62

 

161        15           13           7             -53

 

36           11           20           17           -59

 

48           11           17           23           -67     

 

 

 

 

 

   

Monday, June 3, 2019

How to get B&W white floor plans for your survey

 

Many times I get floor plans that are not the color that I prefer.  I love black and white floor plans – I like to survey with black and white, plan when them in black and white, and if I need to upload them into a NMS, such as Cisco Prime, I fell they look much nicer as well.  I do this because I use colors for the heat maps in Ekahau Pro, and I feel this is a much cleaner look.  But how do we get them into B&W without spending a lot of time on them?

 

I wanted to share how I convert my plans to B&W when I get a colored PDF, such as the snippet of the floor plan below I received recently.  This was a PDF, and as you can see, it has a lot of red walls on there.  Using the Microsoft Snipping Tool, I snipped the floor plan from the drawing and I sanitized it quickly, removing names, etc, by using the “Custom Pen” and selecting the color white.  It takes a few minutes to figure out how to do this, but when you do, it works well.  For me it does, anyway.

 

 

Next, the floor plan needs to be saved.  I save it as a .jpg file, then close it.  Now I open it in Microsoft Paint, and then save it as a monochrome bitmap.  See below:

 

 

 

 

Now the floor plan is saved in black and white.  I close Microsoft Paint and then reopen the file again in Microsoft Paint, saving it as a .jpg.  I do this last step because I sometimes find it doesn’t upload properly into Cisco Prime.

 

This only takes a few minutes and is well worth in if you want clean black and white floor plans without spending hours and hours on them, or spending a lot of money of software that will do it for you.  There is a slight degradation on some floor plans, so you’ll have to see if this is good enough for you.

 

 

 

 

Saturday, April 13, 2019

Comparing Ekahau Connect to the laptop surveying style

I have been using Ekahau for Wi-Fi surveying for some time now, and up until last week I have been using a 13” Dell Inspiron 5000 laptop that flips into a tablet when I want it.  I connect the Ekahau Sidekick to the laptop via USB cable, sling the Sidekick over my shoulder and start walking.  Easy, right?

 

If you are unsure what a Sidekick is you can read about it here: https://www.ekahau.com/products/sidekick/overview/  Not to understate all that it can do, it has two Wi-Fi radios, a spectrum analyzer, a long lasting battery, and now it has storage available inside.  Before the Sidekick, we walked around with a USB hub hanging out of our laptops with a spectrum analyzer or two hanging off it, along with a couple of USB Wi-Fi adapters as well.  All of that was depleting the laptop battery.

 

Wi-Fi engineers are always looking for ways to lighten the load (since we do a lot of walking) when surveying.  We want longer surveying times between charging – usually starting out in the morning and hoping our batteries will last until lunch time so we can charge up.  Unfortunately our batteries rarely get fully recharged over the tiny lunch breaks we take.  Some engineers carry identical laptops with them, and survey until the battery is low then stop and save the survey, transfer it to the fully charged laptop so they can continue surveying and put the other laptop on the charger.

 

Those days are no longer necessary anymore.  Ekahau released a new product called Ekahau Connect.  This allows you to create your WLAN survey project and upload it to the cloud so you never lose your project file.  Then you use an iPad that is also linked to the cloud – it downloads your survey project file and you can now survey with an iPad and the Ekahau Sidekick.  Here’s more on Ekahau Connect:  https://www.ekahau.com/products/ekahau-connect/overview/

 

Why would you want to survey with an iPad?  It weighs less than half as much as my laptop, and is of similar size.  I bought a 12.9” iPad Pro for the job, and when sitting side by side, they look to be about the same.  The iPad, however, is much lighter and a lot easier to maneuver when walking through a building, dodging people and squeezing into areas where you want to gather a data point.  Truth be told, I probably could have purchased a smaller iPad, since it’s almost too big.

 

Since the iPad isn’t as “rugged” as my laptop, I purchased a rubber-like case for it that has a folding handle.  I had to modify it slightly to accommodate the adapter cable to connect to the Sidekick since the iPad doesn’t have the same USB connector as the laptop.  I found the rubber-like case on eBay for something like twenty bucks.

 

During the launch of the new Ekahau Connect, we heard how much better it was, so I decided to test drive it on a validation survey.  I walked the same exact floor twice – once with version 9.2.4 of Ekahau Site Survey running on my Dell laptop with the Sidekick connected, then I walked it again with the iPad and Sidekick.  Now it is time to compare – keeping in mind the same human (me) walked the floor twice.  I tried to replicate the walking path and did not try to walk any faster than I normally do. Now let’s see the results:

 

Here’s the iPad survey.  The red dots are the actual locations of the access points. I would say that is pretty accurate most of the time – within 5 feet or so.

 

 

Here’s the Dell running 9.2.4.  Not sure why the upper left red dot’s AP landed in the middle of the drawing, a good 100 feet away.  I looked at the survey path and there’s nothing funny about it.  Ignoring that, I would say that when comparing, the new Ekahau Pro 10 is more accurate with AP placement.

 

 

 

Now let’s compare walk time:

 

Here’s what the iPad survey time looked like:

 

Here’s what the laptop survey time looked like:

 

Nearly identical – which means carrying an iPad didn’t allow me to unconsciously walk any faster.  I didn’t try to walk any faster, however I can see how the iPad took me two minutes longer since I was not used to carrying an iPad.  I also had to disable the auto-rotate on the iPad since I noticed my survey would flip upside down when walking around because the iPad is so much lighter and I could carry it easier.

 

It is difficult to measure arm, wrist and general comfort when comparing the two.  I feel the iPad is much easier to survey with, for sure.  Since I didn’t survey all day, I was not able to compare battery usage, however I did notice that after having my iPad on, I used less than ten percent of my battery.  Most Sidekick owners already know that it will last for about 8 hours before it needs recharging, and the iPad appears as though it will last even longer.  I can say for certain the strain from carrying an iPad is much less than carrying my laptop.  The specs on my laptop state it is 3 pounds 6 ounces, and the iPad is a pound and a half with the rubber case.

 

My next post will be a validation of a 180,000 square foot building – we expect that survey to take all day and we will test the longevity of the iPad & Sidekick’s battery.

 

 

 

 

Saturday, April 6, 2019

Setting TPC levels for Cisco 3802 deployments

 

When WLANs are designed, many Wi-Fi Engineers use an AP-on-a-stick to survey the site so see how the signals propagate.  Therefore, the access point needs to be set to a particular power, and that is what is usually going to be deployed as well.  I have seen many Engineers use either 25mW or 50 mW for their surveys.  The end goal is to match the transmit power of the access point to the transmit power of the Wi-Fi client.

 

When deployment time comes, they set the WLAN controller’s radio resource management (RRM) transmit power control (TPC) minimum and maximum setting to 25 mW (14 dBm) and 50 mW (17 dBm) respectively.

 

Since this practice has been common for the last ten years, many WLAN controllers out there are set to those numbers.  This setting worked well for the Cisco 3502, 3602 & 3702s on most channels.

 

Screenshots of power reference charts are from Brian Long’s website at http://blong1wifiblog.blogspot.com/

As you can see, RRM will allow the access points to be at either 17 dBm or 14 dBm on most channels

 

 

 

 

And it works somewhat well for the Cisco 3702 – the AP will only have one power setting to choose from on UNII-1 channels:

 

 

Now lets take a look at the Cisco 3800 series access point.  I placed a 3802i series AP on each channel and used the CLI to scrape the information to create this table.

To see the actual output from the WLC, scroll down to the end of this post.

 

 

As you can see, there are quite a few channels out of the lineup that are stuck on one power setting, since the power level sits between 14 dBm and 17 dBm, which is the min/max in the WLC.  That could be a problem if you want your controller to make a power/channel plan for your deployment.

 

Since my goal is to allow the controller to “turn the power up or down a notch”, I looked at the other power levels and came up with a power plan that would allow two power levels for each channel.  This meant I had to increase my maximum transmit power to 18 dBm, and lower my minimum transmit power to 13 dBm.

 

 

I didn’t leave channel 165 out by accident.  The 3802 did not support that channel at the time of the screen scrape.

 

Channel 36

       Tx Power

      Num Of Supported Power Levels ............. 8

      Tx Power Level 1 .......................... 22 dBm

      Tx Power Level 2 .......................... 19 dBm

      Tx Power Level 3 .......................... 16 dBm

      Tx Power Level 4 .......................... 13 dBm

      Tx Power Level 5 .......................... 10 dBm

      Tx Power Level 6 .......................... 7 dBm

      Tx Power Level 7 .......................... 4 dBm

      Tx Power Level 8 .......................... 2 dBm

    

 Channel 40

    Tx Power

      Num Of Supported Power Levels ............. 8

      Tx Power Level 1 .......................... 22 dBm

      Tx Power Level 2 .......................... 19 dBm

      Tx Power Level 3 .......................... 16 dBm

      Tx Power Level 4 .......................... 13 dBm

      Tx Power Level 5 .......................... 10 dBm

      Tx Power Level 6 .......................... 7 dBm

      Tx Power Level 7 .......................... 4 dBm

      Tx Power Level 8 .......................... 2 dBm

       

Channel 44

Tx Power

      Num Of Supported Power Levels ............. 8

      Tx Power Level 1 .......................... 22 dBm

      Tx Power Level 2 .......................... 19 dBm

      Tx Power Level 3 .......................... 16 dBm

      Tx Power Level 4 .......................... 13 dBm

      Tx Power Level 5 .......................... 10 dBm

      Tx Power Level 6 .......................... 7 dBm

      Tx Power Level 7 .......................... 4 dBm

      Tx Power Level 8 .......................... 2 dBm           

 

Channel 48

    Tx Power

      Num Of Supported Power Levels ............. 8

      Tx Power Level 1 .......................... 22 dBm

      Tx Power Level 2 .......................... 19 dBm

      Tx Power Level 3 .......................... 16 dBm

      Tx Power Level 4 .......................... 13 dBm

      Tx Power Level 5 .......................... 10 dBm

      Tx Power Level 6 .......................... 7 dBm

      Tx Power Level 7 .......................... 4 dBm

      Tx Power Level 8 .......................... 2 dBm

 

Channel 52

    Tx Power

      Num Of Supported Power Levels ............. 6

      Tx Power Level 1 .......................... 17 dBm

      Tx Power Level 2 .......................... 14 dBm

      Tx Power Level 3 .......................... 11 dBm

      Tx Power Level 4 .......................... 8 dBm

      Tx Power Level 5 .......................... 5 dBm

      Tx Power Level 6 .......................... 2 dBm    

 

Channel 56

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 18 dBm

      Tx Power Level 2 .......................... 15 dBm

      Tx Power Level 3 .......................... 12 dBm

      Tx Power Level 4 .......................... 9 dBm

      Tx Power Level 5 .......................... 6 dBm

      Tx Power Level 6 .......................... 3 dBm

      Tx Power Level 7 .......................... 2 dBm   

 

Channel 60

Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 18 dBm

      Tx Power Level 2 .......................... 15 dBm

      Tx Power Level 3 .......................... 12 dBm

      Tx Power Level 4 .......................... 9 dBm

      Tx Power Level 5 .......................... 6 dBm

      Tx Power Level 6 .......................... 3 dBm

      Tx Power Level 7 .......................... 2 dBm    

 

Channel 64

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 20 dBm

      Tx Power Level 2 .......................... 17 dBm

      Tx Power Level 3 .......................... 14 dBm

      Tx Power Level 4 .......................... 11 dBm

      Tx Power Level 5 .......................... 8 dBm

      Tx Power Level 6 .......................... 5 dBm

      Tx Power Level 7 .......................... 2 dBm  

 

Channel 100

    Tx Power

      Num Of Supported Power Levels ............. 6

      Tx Power Level 1 .......................... 17 dBm

      Tx Power Level 2 .......................... 14 dBm

      Tx Power Level 3 .......................... 11 dBm

      Tx Power Level 4 .......................... 8 dBm

      Tx Power Level 5 .......................... 5 dBm

      Tx Power Level 6 .......................... 2 dBm

  Channel 104

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 18 dBm

      Tx Power Level 2 .......................... 15 dBm

      Tx Power Level 3 .......................... 12 dBm

      Tx Power Level 4 .......................... 9 dBm

      Tx Power Level 5 .......................... 6 dBm

      Tx Power Level 6 .......................... 3 dBm

      Tx Power Level 7 .......................... 2 dBm  

 

Channel 108

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 18 dBm

      Tx Power Level 2 .......................... 15 dBm

      Tx Power Level 3 .......................... 12 dBm

      Tx Power Level 4 .......................... 9 dBm

      Tx Power Level 5 .......................... 6 dBm

      Tx Power Level 6 .......................... 3 dBm

      Tx Power Level 7 .......................... 2 dBm

 

Channel 112

Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 19 dBm

      Tx Power Level 2 .......................... 16 dBm

      Tx Power Level 3 .......................... 13 dBm

      Tx Power Level 4 .......................... 10 dBm

      Tx Power Level 5 .......................... 7 dBm

      Tx Power Level 6 .......................... 4 dBm

      Tx Power Level 7 .......................... 2 dBm    

 

Channel 116

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 18 dBm

      Tx Power Level 2 .......................... 15 dBm

      Tx Power Level 3 .......................... 12 dBm

      Tx Power Level 4 .......................... 9 dBm

      Tx Power Level 5 .......................... 6 dBm

      Tx Power Level 6 .......................... 3 dBm

      Tx Power Level 7 .......................... 2 dBm  

 

Channel 120

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 18 dBm

      Tx Power Level 2 .......................... 15 dBm

      Tx Power Level 3 .......................... 12 dBm

      Tx Power Level 4 .......................... 9 dBm

      Tx Power Level 5 .......................... 6 dBm

      Tx Power Level 6 .......................... 3 dBm

      Tx Power Level 7 .......................... 2 dBm

 

Channel 124

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 18 dBm

      Tx Power Level 2 .......................... 15 dBm

      Tx Power Level 3 .......................... 12 dBm

      Tx Power Level 4 .......................... 9 dBm

      Tx Power Level 5 .......................... 6 dBm

      Tx Power Level 6 .......................... 3 dBm

      Tx Power Level 7 .......................... 2 dBm  

 

Channel 128

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 18 dBm

      Tx Power Level 2 .......................... 15 dBm

      Tx Power Level 3 .......................... 12 dBm

      Tx Power Level 4 .......................... 9 dBm

      Tx Power Level 5 .......................... 6 dBm

      Tx Power Level 6 .......................... 3 dBm

      Tx Power Level 7 .......................... 2 dBm

 

Channel 132

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 18 dBm

      Tx Power Level 2 .......................... 15 dBm

      Tx Power Level 3 .......................... 12 dBm

      Tx Power Level 4 .......................... 9 dBm

      Tx Power Level 5 .......................... 6 dBm

      Tx Power Level 6 .......................... 3 dBm

      Tx Power Level 7 .......................... 2 dBm

 

Channel 136

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 20 dBm

      Tx Power Level 2 .......................... 17 dBm

      Tx Power Level 3 .......................... 14 dBm

      Tx Power Level 4 .......................... 11 dBm

      Tx Power Level 5 .......................... 8 dBm

      Tx Power Level 6 .......................... 5 dBm

      Tx Power Level 7 .......................... 2 dBm

 

Channel 140

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 20 dBm

      Tx Power Level 2 .......................... 17 dBm

      Tx Power Level 3 .......................... 14 dBm

      Tx Power Level 4 .......................... 11 dBm

      Tx Power Level 5 .......................... 8 dBm

      Tx Power Level 6 .......................... 5 dBm

      Tx Power Level 7 .......................... 2 dBm

    

Channel 144

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 20 dBm

      Tx Power Level 2 .......................... 17 dBm

      Tx Power Level 3 .......................... 14 dBm

      Tx Power Level 4 .......................... 11 dBm

      Tx Power Level 5 .......................... 8 dBm

      Tx Power Level 6 .......................... 5 dBm

      Tx Power Level 7 .......................... 2 dBm

 

Channel 149

    Tx Power

      Num Of Supported Power Levels ............. 7

      Tx Power Level 1 .......................... 19 dBm

      Tx Power Level 2 .......................... 16 dBm

      Tx Power Level 3 .......................... 13 dBm

      Tx Power Level 4 .......................... 10 dBm

      Tx Power Level 5 .......................... 7 dBm

      Tx Power Level 6 .......................... 4 dBm

      Tx Power Level 7 .......................... 2 dBm

 

Channel 153

    Tx Power

      Num Of Supported Power Levels ............. 8

      Tx Power Level 1 .......................... 23 dBm

      Tx Power Level 2 .......................... 20 dBm

      Tx Power Level 3 .......................... 17 dBm

      Tx Power Level 4 .......................... 14 dBm

      Tx Power Level 5 .......................... 11 dBm

      Tx Power Level 6 .......................... 8 dBm

      Tx Power Level 7 .......................... 5 dBm

      Tx Power Level 8 .......................... 2 dBm

  

Channel 157

    Tx Power

      Num Of Supported Power Levels ............. 8

      Tx Power Level 1 .......................... 23 dBm

      Tx Power Level 2 .......................... 20 dBm

      Tx Power Level 3 .......................... 17 dBm

      Tx Power Level 4 .......................... 14 dBm

      Tx Power Level 5 .......................... 11 dBm

      Tx Power Level 6 .......................... 8 dBm

      Tx Power Level 7 .......................... 5 dBm

      Tx Power Level 8 .......................... 2 dBm

 

Channel 161

    Tx Power

      Num Of Supported Power Levels ............. 8

      Tx Power Level 1 .......................... 23 dBm

      Tx Power Level 2 .......................... 20 dBm

      Tx Power Level 3 .......................... 17 dBm

      Tx Power Level 4 .......................... 14 dBm

      Tx Power Level 5 .......................... 11 dBm

      Tx Power Level 6 .......................... 8 dBm

      Tx Power Level 7 .......................... 5 dBm

      Tx Power Level 8 .......................... 2 dBm

 

  

Channel 165

Not supported

 

 

 

 

 

Sunday, March 10, 2019

My modified wifistand for APoS surveys

I just wanted to share what I have done with my WiFiStand for APoS surveys. The WiFi stand can be purchased here:  https://wifistand.com/

 

I started out years ago doing AP-on-a-Stick (AP0S) surveys and trying all kinds of mounts, etc, to get the best rig I could make.  I used to use a flexible extension for a painter’s pole, with a slight modification to keep the rig stable when raised up to a ceiling grid.  I bought some “rare earth magnets” on eBay and taped them to the extension pole so it would cling to a ceiling grid when raised up.  I did not outfit this rig so the AP would be supported by the grid by the magnets – I only used the magnets to keep the grid stable when I raised it to the ceiling so the setup would not accidentally fall over.  Here is a picture of my flexible painter’s pole clinging to a metal rail all by itself with an AP attached.

 

 

Here is what that rig looked like from the side:

 

 

After acquiring a WiFiStand, I had the idea of a modification similar to my painter’s pole rig.  Same kind of rare earth magnet stability, and a painter’s pole adapter.  Here’s what I came up with:

 

I found this paint roller with the same dimension as a ¼-20 bolt, so I purchased it.  It was under ten bucks.

 

 

I cut the rolling part off and was left with the stem:

 

 

I have a tap and die set, so I started threading the stem to ¼-20.  This only took about fifteen minutes.  It was a lot easier than I thought, to be honest.

 

 

This was the first time I have ever put thread on anything, so please don’t judge.  And to be honest, if I can do it, so can you.  It isn’t perfect, but it is my first time threading anything.  I think it definitely does the trick.

 

 

I started to screw it into the WiFi stand, and it works.  It was actually too easy.

 

 

Here is the entire rig, assembled.

 

 

Next I glued some rare earth magnets to the rig for stability, just like my old rig.  Again, this is not to hold the entire rig from the ceiling grid – it is just there to keep everything from tipping over.  I used Gorilla glue to affix magnets to both sides of the frame, and then gave it a quick coat of paint to cover up the magnets and glue.  Here it is:

 

 

Just to show how these magnets can make a rig more stable, I am going to show how strong the magnets are.  Here is the WiFi stand holding a Cisco 2802 series access point to a metal railing without any support other than the magnets.  Again, I do not recommend using magnets to support an APoS.  I simply use them to keep my rig more stable – and it works like a charm.