Posts

Noise Floor Penalty of Wider Channels in Wi-Fi Networks

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I’ve been told a number of times that although wider channels in a Wi-Fi network generally provide a higher connection speed (and hopefully a higher throughout), it comes at the cost of increasing the perceived noise floor of the client device. I thought it would be interesting to test this out for myself. With the advent of 802.11n, it became possible to bond together the 20MHz wide channels of earlier standards in to 40MHz channels (though in reality, this was only practically feasible on the 5GHz band). Several years later, 802.11ac enabled us to bond together even larger chunks of contiguous channels and achieve 80MHz and 160MHz wide channels on the 5GHz band. Though 80MHz channels are not feasible in many environments and 160MHz is limited to very niche scenarios, they nonetheless are options. Theoretically, each time we double our channel width, we are going to double our connection speed and our throughput (there are some protocol efficiencies achieved which mean we may slightly

Ubuntu Wi-Fi Client Information

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When troubleshooting Wi-Fi connectivity issues, gathering information from the infrastructure side of the network is only half of the picture. In addition to understanding how your Wi-Fi network is configured and performing, it is critical to understand how the wireless network looks from the wireless client’s point of view. In this article I present a few useful snippets that may help you if you have an Ubuntu client that you need to investigate. Background Understanding AP channels plans, their transmit power, the coverage that they provide and a whole host of infrastructure-side parameters is very useful when diagnosing Wi-Fi client issues. However, even when you have (what you consider to be) a well designed, well configured network, there may still be some wireless clients that refuse to play nicely on your network. I recently had issues with a number of Ubuntu laptops that were having connectivity issues on a network I was investigating. Once you’ve checked the usual iss

UK 5GHz WLAN Spectrum Allocation (August 2017)

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In August 2017, Ofcom in the UK made some additional channels available in the 5GHz band for license exempt usage. The details can be found in the following Ofcom document:  VNS – Voluntary National Specification 2030/8/3 This means that we have an additional 6 x 20Mhz channels available for use here in the UK for our Wi-Fi networks. This also translates in to a possible additional 3 x 40MHz channels and 2 x  80 MHz channels. I have put together a cheat sheet showing the 5GHz channels now available in the UK, together with a few useful references. You can download the sheet from here: link

Ekahau’s “Game Changer”: Your New Survey BFF

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The phrase “game changer” is banded around a great deal by our good friends in sales and marketing. It seems to accompany  just about every new product or service that they may introduce. Being a techie (and a rather reserved Brit), I’m not one for throwing around such emotional, bombastic language lightly. But after having been given early access to a new product from Ekahau, I’m going to say it: yes…this is a “game changer”. Read on to find out why… (Download a PDF of this article here ) Background If you’re a current user of Ekahau Site Survey (or any wireless survey product come to think of it), you’ll be familiar with the ritual of assembling your survey dongle collection each time you need to perform a wireless survey. To correctly survey, you’ll need at least two dongles gathering Wi-Fi RF data (one per band), together with one or two spectrum analysis dongles scanning both bands of the Wi-Fi spectrum. In most cases, all of the dongles are invariably connected to USB

Odroid Based Speedtest

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Sometimes it would be great to have your own, independent speed-test service to test performance inside your network. In this article, I look at a free speed-test utility that can be installed onto an Odroid platform so you can have your very own network speed-test service. Background Back in February 2017, I attended the Wireless LAN Pros conference in Phoenix. Among the many interesting sessions provided was a “maker” session where we all got to build a whiz-bang gizmo based on an Odroid computer board. This is quite similar to a Raspberry Pi, that you may be more familiar with, but it has a bit more processing horsepower and, most importantly, a gigabit Ethernet connection, rather than being limited to the 100mbps of a Pi. Among the many features that the Odroid provided for us was speed-test software from OpenSpeedtest.com. I’m sure you’ll be familiar with this type of service is you’ve used Speedtest.net or some other similar web-based speed testing utility. You simply br