Thane Sherrington (S) wrote:
At 04:37 PM 03/05/2006, Harry McGregor wrote:
The two common "odd ball" connectors used (incorrectly referred to
here as "standard") are RP-TNC and RP-SMA, reverse polarity SMA and
reverse polarity TNC. The genders are kinda off vs the normal
version of the SMA and TNC connectors.
Ok, thanks for that info.
I personally like Hyper Link Technologies for Antennas, both mobile,
and fixed.
A couple of questions on picking an antenna. Is larger better? How
much difference is there between a 5dBi and an 8dBi?
dBi is logarithmic, so it's a lot of difference between the two. The
big issue is coverage. You can't have gain without loss of gain.
Omni antennas work like a donut, ie it shrinks the vertical to increase
the horizontal.
If you look at the two radiation patterns given for each antenna, you
can see what it's doing.
Here is a 8dBi
http://www.hyperlinktech.com/web/copyrighted_images/pattern_hg2409u.gif
Here is a 5dBi
http://www.hyperlinktech.com/web/copyrighted_images/pattern_re05u.gif
If you are using it in a two or three story house, you would want to
have move vertical gain than if you are using it in a single story house.
Directional antennas increase gain by reducing the radiation pattern
even more. The 14dbi directional that I listed has a 30 degree by 30
degree beam width, while the 8dbi directional "smoke detector" has a 60
degree by 60 degree beam width.
Also remember that this increases transmit power receiver sensitivity at
the AP. Depending on the card you have (laptop with built in card?),
your range may not improve as much as you might expect.
One of the first things I do for "fixed" wireless installs
(workstations) is put a light duty external antenna on the desktop
machine, moving the antenna out from behind the system, and giving it
better visibility.
Here is a wonderful option for that (most desktop cards use RP-SMA
connectors)
http://www.hyperlinktech.com/web/re05u.php
Harry
T
