Sunday, October 25

Build your own directional with antenna

Everyone knows how short range WiFi can be, and how easy it is to slow down your connection speeds with interfering signals from neighbors running at the same channel or a leaky Microwave oven during dinner times.

I first tried using a wireless booster. To impress on the promise of a effective solution I acquired the most powerful 1Watt booster I could find on Ebay. Knowing that the default transmission output on most WiFi devices being in around the 0.025 Watt range, I was absolutely sure that I should be able to notice a definite increase in my range. I even tried ordering several Chinese knock-off 9dbi and 12dbi antenna's as well. I performed empirical tests with a Pocket PC and two computers in fixed positions away from each other over a extended period of time to achieve accurate results.

Antenna's:
  • I performed tests with the antenna's and compared signal levels achieved. I also used the stock 2dbi antenna, the 5dbi antenna which came with the booster and the 7dbi antenna from D-link. The results were quite surprising.
  • The 5dbi Antenna had boosted the signal slightly.
  • The Dlink 7dbi antenna had boosted the signal even better. Using the corded stand had a 2% signal loss on average (Not bad)

All the other non-brand name antenna's worked with a signal level comparable to or worse than the stock 2dbi antenna. It would have seemed that the knock off's were either not manufactured properly or were mismatched to the used frequencies.

Aside from the signal quality, the Chinese Knock-off's either were advertised at different gains for the same antenna's and quite often you are unable to use the antenna without the corded stand as they use a proprietary gendered connection type which is not usable with real life WiFi units. Disappointed in them I threw them out rather than trouble myself with spending time repackaging and paying to ship them back to China. So I decided to use the D-link antenna as my first choice before proceeding further as it was the "Only choice".

Boosters:
I tested the 1Watt boosters for 6 months straight. After 6 months I had all the boosters degrade to a failed mode where they actually worsened the WiFi signals. In the beginning however they did boost the range of the WiFi but only noticeable on the transmission aspect of things. The boosters work by switching between transmit mode and receive mode in a "Half-duplex" manner. It must be able to detect when the WiFi device is trying to transmit and switch into the transmit mode to do so. This usually takes time to go into the transmit mode, which they refer to as "Time Division".

That means that it can only transmit or receive at any given time plus a delay factor while switching between the two modes which slows down your capable speeds. After removing both my boosters it has increased my speeds by 3 times. If you plan on using strictly 802.3b(10Mbps) then you may not notice much degradation in speed, but you sure do notice it dragging it's feet at 54Mbps or higher speeds. Anyone trying to extend WiFi range with these boosters "MUST" use boosters at both ends of the WiFi. It will not work simply having one booster at the source as it only significantly amplifies the transmissions.

You may be able to see the boosted signal two blocks away, but you will never be able to connect to it without boosting your signal as well. Nevertheless, my boosters are garbage now. If you plan on going this route, you will find your costs of expanding your range to be expensive and only partly reliable. I would suggest buying a model of booster which has a brand name on it and a time division capable of keeping up with the fast 802.3G/N WiFi devices made today. I abandoned the use of them entirely as a result of my failures to get it to work well enough.

USB WiFi devices are sorta so-so because the Ethernet WiFi devices can be used at the end of a really long cable, where you are limited with length using USB. You also can use Ethernet WiFi devices when connected to networks (Between routers, or joining networks with one router and multiple access points and multiple switches.. In general you have more flexibility and compatibility when using Ethernet WiFi equipment. I don't understand why USB is so popular despite it's limitations.

PCI cards are a joke as well as most of them are behind your computer with a fixed antenna in poor locations offering little to no benefit at all over Ethernet devices. However PCI cards sometimes offer you a more comprehensive control over reporting more WiFi details than your USB devices. Again, you need a wireless device for every computer you have as you cannot share the connection easily in a network.
Routers are sometimes equipped with two to three antenna's. Having to use Parabolic reflectors with multiple antenna's is not only difficult but also expensive as you need to double to triple the cost of extending your range by use of boosters or reflectors. Doesn't make sense to me having anything equipped with more than 1 antenna.

Ranges with WiFi is so "Near" that it is easier to drag a Ethernet cord between my computers which are close enough to do so. Having to introduce latencies, intermittent service outages due to interferences, security holes with WEP/WAP AND increasing the hardware requirements and costs in actually using WiFi at reasonable distances is in most cases easier to simply run a cable.

Ethernet Access Points often are toted around by D-link and Linksys as being just that Access points. Be very careful with what you buy as these manufacturers quite often lure you into thinking that you will be able to use the AP to connect to your router. They often play with terms like Access Point or Bridge Mode WiFi and strip out all the features out like being able to do site surveys, repeater mode with client association, multiple bridge mode (Link multiple routers), or allow using a DHCP server. I have yet to find a WiFi device that I liked.

Closest thing I could find that would give me some signal levels and options was a Netgear WG602 Access point. However that unit has some nasty firmware bugs and 4 hours over the phone with Netgear support tells me that they are not willing to admit it or incapable of understanding why. Buy these units only if they are inexpensive enough to compensate from the troubleshooting time of hardware resetting them every time you change a setting in the wrong order.

Overall Ethernet Devices are the best because you can hook them up to the end of a inexpensive and up to 100 foot length of cable. Repositioning these devices to the ideal location is a snap and networking them to multiple computers is a no-brainer. As such is in my opinion Ethernet is the ideal choice.

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