increase wireless speed

[diablo1]

one router belkin 54g at one end of the house and have two dlink wda 2320 on other side of house connected to 2 desktops. distance is thru many walls and i lose speed from the distance on other two computers... i was wondering if i added a TRENDNet Dual-band 7/5dBi Indoor Omni Antenna with Mounting Base, 802.11a, g, b to each dlink instead of the small antenna that came with them ?? would i get a better connection for the best speeds available considering the distance or are these exteranl antennas just a waste of money ???



http://www.compusa.com/products/prod...44143&pfp=oct7


thanks

[jdharm]

It will help somewhat, just because you would be getting the antenna from behind the metal case of the computer. If the antenna has the case of the computer between it and the router then the case is reflecting the signals from the NIC away from the router and signals from the router are being blocked by the computer case. So the antenna you linked to would help the situation by getting the antenna above the interference of the case.

However, using an omni will not perform as well as a directional:

http://www.compusa.com/products/prod..._code=52032236

The directional will concentrate all the power of the NIC's transmitter in a single beam instead of diluting it by spewing it in all directions at once as the omni does. It will also capture more radiation from the router, increasing the received signal strength at the NIC.

If you want the router's signals to be radiated in all directions so that you can connect roaming clients, like laptops, then leave the stock omni antenna's on it. But if you only use the router as a wireless link to the two stationary desktops then you would strengthen the link by putting directionals on the router, for the same reasons as above. You could put on new antennas, or you could convert the current antennas to directionals by adding reflectors to them.

I have done this several times and it works pretty well, given that it costs practically nothing. About 15 minutes, a little aluminum foil, a cereal box, a little Elmer's, and your omni antenna is now directional. You have a couple options to play with to see which works best for you.

Tall parabolic with informative information.
EZ-12 paraboloc reflector
EZ-10 corner reflector

[diablo1]

do directional anntenna both send and receive signals. im looking for a bi-directional antenna one that recieves the signal and also can i add an amplifier (signal booster) between my dlink wda 2320 and the antenna to try to grab and boost a better signal?

for example, on this product it say directional but does it mean it only sends out a signal http://www.compusa.com/products/prod...ct_code=336429.



will this setup work, dlink wda 2320 plus wifi amplifier (booster) then add an a better anntenna or do they sell one unit with both signal booster and antenna

what terms do i look for, starting to get confused with omni direction, signal booster wifi amplflier, etc..

[jdharm]

Directional antennas both send and receive. They are called directional because the radiation they emit is confined to a narrow "beam" that points in a one direction. It is also only able to listen and receive radiation in that same narrow beam. This is as opposed to omni directional antenna that emits the radiation in all directions at once and can receive signals from any direction equally well.

If the RF radiation were light, then the directional antenna would be a flashlight and the omni would be a bare light bulb. When you shine a flashlight the entire output of the little bulb is focused on a small spot, lighting it well. If you unscrew the reflector and have only the bare little bulb, with nothing to focus the light, the light will radiate in all directions at once giving a very dim light everywhere.

There are advantages and disadvantages to both. When the light of the flashlight is focused on a spot you can see it really well. The trade-off is that you can't see anything else around you because all the light is going to one place. If you take the reflector off, you now get light in every part of the room and you can see everything around you. The trade-off is that the same amount of light is now spread out over a much larger area and you won't see anything nearly as well as you did with the reflector on the flashlight.

The directional antennas will focus all their energy in one spot, increasing their range over an omni, which spreads out the same amount of energy over a large area at the expense of range. Directionals will gather radiation over their entire surface, increasing received signal strength over an omni, which only gathers whatever radiation strikes the thin wire that it is made of. For a point-to-point solution, directionals are the way to go.

Directionals must be aimed very accurately and are very sensitive to being out of alignment with one another. They will send and receive signals only from devices directly in their line of site. For the ability to connect to a moving targets, such as a laptop that can be anywhere at any time (called point-to-multipoint) they are no good at all. Omni is the way to go.

You can get amplifiers, but you start to get into some complicated technical and sticky legal territory. There are federal limits to how much power your system is allowed to put out before the feds come down on your head and finding the power of your system gets very complicated since it involves a lot of variables. On the technical side, the problems you are having with signal strength is likely a function of the environment you are in (RF and physical interference) and raw power isn't likely to solve the problems. In fact, more often than not adding an amp makes environmental problems worse.

Your best bet is to experiment with antennas. Try the free paper and foil reflectors. If you see any improvement at all (use Netstumbler to see the affect you are having), even if it is not what you are looking for, then you know you are on the right track and some purchased directionals might be a good idea. If you see no improvement at all in signal strength, then your problem might not be solvable without changing the conditions of the environment...removing obstructions, moving the antennas, etc.

[diablo1]

how bout this tin can antenna ? does this setup work or is it just a junk article on the net? http://www.turnpoint.net/wireless/cantennahowto.html
is this can antenna a directional or an omni antenna?

i read somewhere the ridges on the can causes bad connections

so the antennas on routers and on PCI cards are all omni?

[jdharm]

how bout this tin can antenna ? does this setup work or is it just a junk article on the net? http://www.turnpoint.net/wireless/cantennahowto.html
is this can antenna a directional or an omni antenna?

It is a directional. All the RF energy is directed out the open end of the can.

It may or may not be junk. It all depends on the materials and precision with which it is constructed. It is exceedingly easy to be off enough in element length and placement, waveguide shape and size, electrical joint integrity and resistance, etc. to completely screw up the whole thing. There are a lot of variables with tight tolerances. It's another reasonably cheap experiment (if you can get the parts locally), so give it a shot if you feel up to it.


i read somewhere the ridges on the can causes bad connections

Dunno. That sounds right though. You're in the microwave RF range...small wavelengths. The height of the ridges - reflective surfaces at odd angles with the axis of the desired radiation pattern - are significant fractions of the wavelength of the RF waves and therefore could have significant impact on their behavior. I could see reflected waves creating an interference pattern with the main emission or doppler shifting into noise that muddies the clean transmission you are after. That's just an educated guess on my part, but I can't imagine the ridges being anything but a complication.

so the antennas on routers and on PCI cards are all omni?

I won't say "all". A general way to tell is if the antenna is a like a whip antenna (long and thin) then it is probably omni. If it is a round dish (like a satellite dish), a square flat panel, a stretched rectangle (like 1:3 or greater aspect ratio), a tube (like the cantenna you linked above), or with several elements (like the VHF TV antenna on your roof) then it is probably directional.