WiFi Range-Hacks
Mitch Epley
Have you ever bought one of those cheap WiFi spy cameras? You know, the ones you pay $1.95 for on E-Bay (plus 19.95 for shipping?) Gotten it home, or into your lab or workshop and set it up and Voila! You have the world at your fingertips, video wirelessly! Except when you deploy it, and realize you’re only getting 8-10 feet of range and it’s choppy at that? What about model airplanes with an inventively attached camera, or a R/C car? Cheap wireless cameras are plentiful, and they just don’t always fulfill the expectations. Always remember, “You get what you pay for.”
Now, having said that, how do you fix the issue?
One, your typical battery operated, covert device is usually running on a very small, low current power source. 9 volt batteries, maybe a few penlight cells, if you’re really small, maybe even a couple of button power cells. These are ok, but not really calculated for strength, or longevity. A simple fix, often is increasing the current, hence the available power to the wireless transmitter or device. Now you don’t want to increase the voltage, but increasing the available current capability may just give you the added power to overcome some of your distance limitations with your WiFi.
Simple enough to do, but it might take some small skill with a soldering iron. Primarily, the easiest method is to take the same battery setup, currently powering your device and double it. If you have 1- 9volt battery, a second battery attached in PARALLEL will keep the voltage the same, but double the available current capacity in your device. Increasing your current capability should give you more power for your WiFi transmitter and assist you in increasing your reception and transmission range. It may require you to be creative on how you hold, and attach the additional batteries, but I have confidence in you. For those of you who aren’t sure about the difference between Parallel and Series connections, check here (FYI this only works on DC or direct current power situations, do not try to tie two AC transformers together!)
Two, essentially the same issue. How do I boost my reception range? If additional power is not the answer, you’ll probably have to resort to antenna modifications to achieve your goals. There are many different styles of antenna, but they mostly boil down to two main types, Directional, and Omnidirectional. Directional antennas point in one direction or field only, and outside of that area, reception is nil, or next to it. Not a good alternative to anything mobile, or if you want to be able to roam freely while receiving. Omnidirectional, which is usually the type on most commercial devices is usually just a pole or wand antenna and can receive in any direction. (We’ll talk about polarization later)
One, the yaggi, a directional antenna, (sounds like shaggy) is a series of elements precisely calculated for length and spacing that focuses and directs ambient signals to an “active” element and thus concentrates the signal. Very precise, and relatively hi gain. You can build one, and I’ve included the link here.
Two, a second directional method is the parabolic antenna, just like the common Satellite TV antenna you see on lots of houses. This one is much easier and requires much less work. The gain is not as high, but a 25-50% increase in signal strength is not unreasonable. Again, here’s a link to build one.
For a Omnidirectional (from the Latin, Omus, meaning “Where the hell am I?) You get an antenna that you can receive signals from in any direction. (Well almost, we’ll get into that a bit later.) Your standard wireless camera usually comes with a whip style antenna. That’s the “pole” sticking out of the side of your device. It’s usually mounted on some sort of swivel. Now you can pay for a “Upgraded antenna, with increased range” or you can make one simply enough…for about 5 cents.
Again, I’m going to direct you to a link, because it’s just too long to go into all these descriptions on this post. Omnidirectional booster antenna link
Just a quick note on antenna polarization, it simply means, if the transmitter antenna is sticking straight up, your receiver antenna should be sticking straight up too. If the transmitter is horizontal, the same applies to your receiver. Make sure the antennas are “polarized” properly for maximum reception strength. This applies, obviously to the omnidirectional antenna mostly, but can apply to the other tow antennas described, your just have to play with them a bit for optimal reception.
Now for some Technical information you might want. I’m sure you can find it on the Internet, but it’s always helpful to rebroadcast this kind of thing.
Remember, Wi-Fi networks have limited range. A typical wireless access point using 802.11b or 802.11g with a stock antenna can have a range of up to 120 feet indoors, and 300 ft outdoors typically, under excellent conditions. IEEE 802.11n, however, can exceed that range by more than two times. Range also varies with frequency band. Wi-Fi in the 2.4 GHz frequency block has slightly better range than Wi-Fi in the 5 GHz frequency block which is used by 802.11a. On wireless routers with detachable antennas, it is possible to improve range by fitting upgraded (or modified!) antennas which have higher gain in particular directions. Outdoor ranges can be improved to many kilometers through the use of high gain directional antennas at the router and remote device(s). Remember, WiFi frequencies are very susceptible to interference. Walls, especially kitchen and bathroom walls between you and your receiver can be particularly annoying. Metal pipes, cast iron bathtubs, refrigerators, stoves, freezers, microwaves… Especially Microwaves can all reduce signal strength to inoperable levels.
Due to reach requirements for wireless LAN applications, Wi-Fi has fairly high power consumption compared to some other standards. Technologies such as Bluetooth provide a much shorter propagation range of 5-20 feet and so in general have a lower power consumption. Other low-power technologies such as ZigBee have fairly long range, but much lower data rate. The high power consumption of Wi-Fi makes battery life in mobile devices a concern. (More current capability, the longer life, and better transmission power/range!)
The practical range of Wi-Fi essentially confines mobile use to such applications as inventory-taking machines in warehouses or in retail spaces, barcode-reading devices at check-out stands, or receiving/shipping stations. Mobile use of Wi-Fi over wider ranges is limited, for instance, to uses such as in an automobile moving from one hotspot to another. Other wireless technologies are more suitable for communicating with moving vehicles.
Hope this helps ,… Good luck!