Does Wi-Fi cause radiation sickness?

Back in the 1970’s when I joined the military, I was in a Scout platoon and I was trained as a Ground Surveillance Radarman, MOS 17K.  The device that we used created a radio wave in the J Band (16GHz).  We used headphones to listen for changes in the 10KM area in front of us. We learned to be able to detect tanks, jeeps, and if we were really good, we could detect people moving through the area. The nomenclature of the Radar was AN/PPS5. It had a 1 degree bandwidth and a 50dBm transponder.

The old-timers in the platoon would tell the newbies, “If you stand in front of the radar for too long it will make you sterile.”

Apparently that wasn’t true because those guys spawned a new generation of tin-foil hat wearing crazies that claim Wi-Fi signals can harm you if you stand in front of an Access Point, or hold your smart-phone too close to your head.

Wi-Fi is based on creating radio waves in the 2.4 and 5GHz bandwidth spectrums. They are specific frequencies, created by an intentional radiator that emit from a directional antenna. The radio waves are part of the electro-magnetic spectrum, just like light waves, x-rays, and gamma-rays. As part of the electromagnetic spectrum, Wi-Fi radio waves travel at the same speed as other radio waves, so if anyone ever complains that the Wi-Fi is slow you can tell them that it’s travelling at the speed of light (300,000,000 m/s)!


The radio waves in 2.4 and 5 GHz measure approximately 5.5” and 2.25” respectively, so they are not small enough to penetrate cells in our body and thus pass through. Our bodies do absorb some of the energy that is emitted from an intentional radiator as it passes through us so the question is, how much power is emitted from a wireless access point?

Wi-Fi is a very low power technology. The amount of power generated has to match the power domain of the devices that the access point will support, otherwise our smartphones and computers would be able to receive the signal but the access points would not be able to detect the incoming signals due to a power mismatch.  That signal strength has been determined to be around 20dBm. At this power level smartphones can create the power needed without needing to increase the form factor of the device.

You might ask, how much power is 20dBm? DBm stands for decibels per milliwatt.  It’s an algorithmic representation of power based on the watt measurement system. 20dBm equates to 100mW which is one tenth of one watt. So the total amount of power that is emitted from an Access Point, and measured directly on the face of the AP, is one-tenth of one watt.

As the Wi-Fi radio wave travels through the air it loses power so that after the wave travels one meter the strength has dropped by 40-47 Db, so that at one meter out the signal strength will be less that one milliwatt. Not enough power to do much more than elevate a radio-wave above the noise of other radio waves and definitely not enough power to affect our cellular tissue.

The AN/PPS-5 had an Intentional Radiator of 50 watts, so it was considerably stronger than a Wi-Fi Access Point. It created waves in the J band, which is in the 16 GHz range. That converts to about .75 inches wide, still, hundreds of times larger than a cell.  So even though I spent a lot of time in front of our Ground Surveillance Radar system, I was still able to produce a normal family.


Blessings from the Webers!

Training with then Cloud Gen2+

This weekend I’m headed to Orlando to teach a Sat/Sun class on UniFI. I’ve started using the UCK-Gen2+ and creating “sites” for each user. This is turning out much better than having students create their own controller on their PC. It still gives students the capability to configure the controller. Now each student gets two ports on a switch and they connect their computer and an AP into a VLAN that’s created prior to class. That way they can control the AP and make config changes.

This week I’m bringing along a SHD that we can look at because it has AirView and AIrTool on it. Two very nice tools that I’d like students to see. We are still using the AC-Lite APs, which I like a lot.

I recently bought an LTE, but I haven’t installed it yet. Maybe we will get a chance in an upcoming class. I’d like to use it because WiFi in the hotels is almost always sketchy. Hopefully I can transition over soon and make it part of the class.

Memphis Training

The Memphis training will be held at the FedEX Forum, home of the Memphis Grizzlies NBA basketball team.  The FedEX forum uses Ubiquiti to provide Wi-Fi in the forum that seats 18,000 people.

We are holding the class in a conference room there and we will be with the expert team that supports this facility. The FedEx forum uses the new Basestation XG as their primary Wi-Fi interface.

Come join us for a special time in Memphis.

Wireless Adjuster
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Recently I got a chance to participate in the beta program for the new Wireless Adjuster class being developed by Devin Akin  For those that don’t know Devin Akin, he is one of the Wi-Fi industry’s leaders. He has a very impressive resume and I encourage anyone interested Wi-Fi to get to know Devin. You can follow Devin on Twitter (@DevinAkin), which is the default communication platform for Wireless LAN professionals.

The Wireless Adjuster class is an excellent course designed to give Wireless Professionals a platform to perform troubleshooting using Spectrum Analysis tools. The primary tool for this course is Wi-Fi Explorer Pro.  The class also looked at Metageek’s InSSIDer as a Windows alternative, but most of the class was spent on Wi-Fi Explorer Pro.

Last year at the Wi-Fi Trek conference Keith Parsons from WLAN Pros presented on Wi-Fi troubleshooting. His presentation shed light on the need for a troubleshooting knowledge domain.  He addressed it and posted it here

The Wireless Adjuster class addresses one of the six education domains that Keith identified; the Investigate Domain.

The class is designed to be a hands-on training class and it definitely is that. After an in-depth overview of the capabilities of Wi-Fi Explorer Pro we started analyzing different Wi-Fi problems using the tools.  I was somewhat familiar with the tool before the class, but the guy sitting behind me was really knowledgeable. Adrian Granados, the developer of Wi-Fi Explorer, was with us. Together we explored the intricacies of the spectrum analyzer that has become the “go-to” tool for Wi-Fi professionals.

Day one also featured an in-depth look at the Wlan-Pi device. We connected to our Pi’s through Wi-Fi Explorer Pro so we could see how to get Spectrum Analysis data from a remote device. This is a great way to troubleshoot network problems remotely. Wi-Fi Explorer Pro has a dropdown menu that allows you to choose Active, Passive, Directed, or Remote. Once you connect to a remote Wlan-Pi you can start using Wi-Fi Explorer Pro to display scans from your remote site.  

We also connected a Metageek WiSpy spectrum analyzer to our computers to get additional views of the wireless spectrum. This wasn’t my favorite part of the class, but I can see how it could be useful to see if there is something other than Wi-Fi that is causing interference in your environment. 

The second part of day one and the entire second day we spent troubleshooting network issues.  Devin gave us a scenario where a customer was complaining about bad Wi-Fi and then we were given a list of possible causes. It was our job to test out the possible choices and determine the cause of the problem.  This was a great way to familiarize ourselves with the tool.  We had to dig deep to see how the infrastructure had been configured, or rather, misconfigured to cause the problem.

We had a couple of APs that Devin configured in the class, and then the nine of us would start snooping to find the best answer. After that we would critique his answers. We were brutal – to him and to each other. Devin had a fun question delivery tool that he was using to keep score called Kahoot. After our critique of Kahoot during the class comments I think he’s going to pull Kahoot and use a different delivery method, but it was fun while it lasted.

The Wi-Fi Adjuster course is a great course to help fill a gap in Wi-Fi training. It’s aimed at professionals that have CWNA level knowledge of Wi-Fi.  Devin says that he has plans to create a “level-one” Wi-Fi Adjuster class that would be for professionals that don’t have that level of expertise, but right now he has his hands full with the demand for this level of training.

Thanks to Devin, for addressing an area of Wi-Fi training that is sorely missing.

Ubiquiti Cloud Key Gen2+

The Ubiquiti Cloud Key Gen2+ is a great tool to manage your network and your video. You can run up to 15 cameras (maybe a few more but not recommended). All for $299.00.

The new Gen2+ is the only way I know of at this time to host UniFi Protect Video cameras. I learned that the hard way. I bought a $79.00 G3 Flex Camera and tried to get it to connect to my UniFi NVR. I couldn’t figure out why it didn’t work until I read the user guide (imagine that). It was time for me to upgrade my Cloud Key anyway so I sprung for it and I’m glad I did.

More later…