Higher gain equals less coverage?

[RamGuy]

After reading a bit about wireless signals and antennas, it sounds to me like the "higher gain / dBi" equals better coverage, higher throughput and overall better wireless experience is a myth?

After what I understand the higher gain simply focus / compacts the signal, making it stronger within specific radius, but rendering things even worse if you are located outside this compact signal / beam?


So if you have a wireless device supposed to provide great wireless signal throughout the entire house higher gain / dBi might actually make things worse compared to the standard 2-4dBi low gain antennas that ships with common D-Link and Linksys devices?

 

[thiggins]

Higher gain itself does not "focus" an antenna. But higher-gain antennas tend to be directional vs. omnidirectional, which does affect coverage.

 

[claykin]

Also the cable that comes with these antennas introduces loss. Cheapy consumer antennas don't have high quality low loss cabling and at 2.4Ghz loss is as much as 3db over a 3 foot cable.

Plus these antennas play with the radio transmit/receive shaping. The radio is designed to work with a certain gain and antenna type. When switching it up, the result could be bad. This is especially true with MIMO radios that are in pretty much all modern routers.

The best solution is something like that employed by Ruckus and to a lesser extent Rayspan (Netgear's antenna OEM)

 

[RamGuy]

So what would be recommended to use with a 500mW High Power AR9220?
Something regular like the stock D-Link DIR-855 antennas or something higher gain?

 

[saturation]

As I recall my ancient studies, antenna gain is not like amplifier gain, as you suggest its a combination of higher "sensitivity" in a given direction, better being measured relative to the sensitivity it gets when it radiates equally from a point within a circle. Rather than 'waste' energy radiating to areas were there is no device to receive a signal, you can 'focus' it to were you need it most. Recall, the Wifi output power amps and receiver amplifier gain ultimately are constants, leaving the antenna as something you can do something about, and sometimes to wonderful effect:

http://www.usbwifi.orconhosting.net.nz/

That's my favorite, but I have to stop by my local Asian store to find a Chinese drain spoon. We successfully got better reception from a home AP by making a parabolic 'focuser' out of cardboard and tin foil on a standard wifi whip antenna.


http://en.wikipedia.org/wiki/Antenna_gain

After reading a bit about wireless signals and antennas, it sounds to me like the "higher gain / dBi" equals better coverage, higher throughput and overall better wireless experience is a myth?

After what I understand the higher gain simply focus / compacts the signal, making it stronger within specific radius, but rendering things even worse if you are located outside this compact signal / beam?


So if you have a wireless device supposed to provide great wireless signal throughout the entire house higher gain / dBi might actually make things worse compared to the standard 2-4dBi low gain antennas that ships with common D-Link and Linksys devices?

 

[jdabbs]

So what would be recommended to use with a 500mW High Power AR9220?
Something regular like the stock D-Link DIR-855 antennas or something higher gain?

The question you should be asking is what antenna radiation pattern is best suited for your desired coverage area.

 

[saturation]

Here's a good diagram on antenna gain, and a quick no-nonsense description:

http://www.rfidsb.com/tm/wp-content/uploads/2008/04/antenna.jpg

 

[thiggins]

You might also look at:
How To Fix Your Wireless Network - Part 3: Increasing Coverage
How To Fix Your Wireless Network - Part 4: Antennas