WiFi is very common now for connecting computers and smart devices to the Internet. It’s wireless… no wires. Very convenient! If only we could charge all of our electronic devices without wires. (See cable clutter tips)
There are 2 different major WiFi frequencies available to the public: 2.4 GHz and 5 GHz. Having the frequency in this GigaHertz (GHz) range allows the signal to carry a lot more data, hence faster than lower frequencies. In the early days, we used 900 MHz with much slower speeds.
WiFi implementations adhere to different standards, specifically 802.11 which now comes in a variety of flavours:
802.11a uses 5 GHz frequency and can transmit up to 54 Mbps (Megabits per second). It is fairly good at avoiding interference as well by using OFDM (orthogonal frequency-division multiplexing).
802.11b is the slowest inexpensive solution. It is a 2.4 GHz frequency standard that was popular when cost was a concern but now everyone wants bigger-better-faster so it isn’t as popular. It is rated for 11 Mbps.
802.11g uses 2.4 GHz and can transmit at 54 Mbps. It uses ODFM like 802.11a
802.11n is currently the most popular and is backwards compatible. It can communicate up to four streams of data at 150 Mbps each using 2.4 GHz or 5 GHz. Previous a/b/g could only use a single stream. Also even though it can communicate up to 4 streams doesn’t mean the wireless access point supports it.
802.11ac is the newest released in December 2012 and also backward compatible. It is still being worked on. This one is geared at 5 GHz and has up to 8 streams of data at 450 Mbps each. It has a number of nicknames already such as Gigabit WiFi, 5G WiFi, and VHT (very high throughput).
From a potential interference point of view and of possible interest to you, other devices that operate in the 2.4 GHz range for example are some cordless phones, Bluetooth, microwave ovens, and some baby monitors.
Realize that when more than one wireless device is “sharing” the airwaves, you are also sharing the bandwidth available. And the speeds listed above are theoretical maximums when in reality it is much slower.
Also just because you have the latest and greatest WiFi adapter/support on your device, doesn’t mean that the wireless access point you are communicating with supports your speeds.
And to top it off, we usually run into congestion further up the line (further upstream from you) when connecting to the Internet. Your downloads from some website are only going to be as fast as the slowest link in the chain.
Therefore there is a lot that comes into play when wanting to get the fastest possible downloads so you can watch those 1080p 3D movies and backup the bazillion megapixel images your latest camera takes.
In situations where you have a dual band wireless access point shouting out in both 2.4 GHz and 5 GHz, I will use 5 GHz which tends to be less common and have more of the airwaves at my disposal. This assumes that your own device supports both.
Keep your eyes open for the new 802.11ac and 802.11ad which will hopefully support “ludicrous speed” (ref: Space Balls) as we can’t seem to download what we need fast enough. Part of the issues of being an instant gratification based impatient society. I want it yesterday.