Newbie with wireless antennas

Can Someone please guide me to a good walkthrough website for wireless
antenna tutorial. I am very confused with the terms used. for
example -95dbm. I have no clue what it means.

Any help will be greatly appreciated.

Thanks

db is a ratio based on logarithms with a base of ten. 10 raised to the
second power would be 100 so the log of 100 is 2.0 or 10 times 10. This
power is called the Bel. However, since the bel is too big it is multiplied
by 10 (deci) and called the decibel. In general, power which makes a
difference follows a logarithmic scale and not a linear scale. When you see
dBM or -dBM the reference is one milliwat. In other words -95 dbm is ten
times the log to base ten less than one milliwat. The bigger the number in
minus dbm generally speaking the more sensitive the receiver. -95 dBM is
pretty sensitive. While dBM is really a power ratio it is misused greatly
for other measurements. Hope I got it right and hope this helps. Cheers


"Peace" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Can Someone please guide me to a good walkthrough website for wireless
> antenna tutorial. I am very confused with the terms used. for
> example -95dbm. I have no clue what it means.
>
> Any help will be greatly appreciated.
>
> Thanks
>
>

Thanks a lot for your help. How about the different antennas such as yogi.

Sorry if I am asking too much
"Gator" <(E-Mail Removed)> wrote in message
news:bohat1$1euov9$(E-Mail Removed)...
> db is a ratio based on logarithms with a base of ten. 10 raised to the
> second power would be 100 so the log of 100 is 2.0 or 10 times 10. This
> power is called the Bel. However, since the bel is too big it is
multiplied
> by 10 (deci) and called the decibel. In general, power which makes a
> difference follows a logarithmic scale and not a linear scale. When you
see
> dBM or -dBM the reference is one milliwat. In other words -95 dbm is ten
> times the log to base ten less than one milliwat. The bigger the number in
> minus dbm generally speaking the more sensitive the receiver. -95 dBM is
> pretty sensitive. While dBM is really a power ratio it is misused greatly
> for other measurements. Hope I got it right and hope this helps. Cheers
>
>
> "Peace" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> > Can Someone please guide me to a good walkthrough website for wireless
> > antenna tutorial. I am very confused with the terms used. for
> > example -95dbm. I have no clue what it means.
> >
> > Any help will be greatly appreciated.
> >
> > Thanks
> >
> >
>
>

minus 95 Decibels of noise found in antenna.

In general antennas get their gain by "focusing" their radiated power. There
are several schemes. The Yagi has been around for quite a while and
generally consists of a "driven " element and reflecting and directing power
from the driven element. The element lengths are adjusted i n length and
distance from the "driven" element so that energy arrives in phase and is
reinforced in a forward direction. There are others such as the co-linear
which can be used in other planes which consists of two elements generally
separated by a phaser so that they reinforce the output signal. Decibel gain
for an antenna such as gain for an antenna is generally the gain over an
isotropic antenna. That is, an antenna somewhat theoretical located in space
with no surrounding interference from trees, etc. etc. This gain has a
reference of dbi.. Or gain over an isotropic antenna. 3 dbi would be double
the gain. Usually will be somewhat like 6 dbi or 4 times gain. Anytime you
have gain you are simply focusing what is available somewhat like but not
exactly like focusing a light. A parabolic reflector is a good one, a Yagi
is a good one. The Cantenna widely known can be a driven waveguide or a
reflector with a probe, Yagi, or some other manner of introducing the RF.
Generally speaking the available electromagnetic energy is redirected and
concentrated in some direction taking away from other directions. Hope this
helps and hope I got it right. P.S. If a manufacturer says your antenna has
so much gain it is generally dbi gain and will be plus dbi gain. Luck!!


"Peace" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Can Someone please guide me to a good walkthrough website for wireless
> antenna tutorial. I am very confused with the terms used. for
> example -95dbm. I have no clue what it means.
>
> Any help will be greatly appreciated.
>
> Thanks
>
>