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Yacht Cellular WiFi Antennas - dB gain and dB Myth/Marketing
When a yacht Internet Connection system of the WiFi or Cellular type is
installed on a yacht, usually there is an amplifier a coaxial cable and
a marine
type omni-directional antenna. That will be one of those 2 to 4 foot
(approx.)
white vertical antennas. They have to be made specifically for the
application,
which means the purpose and frequency band or band(s) that it will be
used for.
Often these antennas have a specification as to Gain. Antennas don't
really
amplify a signal, they cannot. They are not an active electronic
component, meaning there is no powered electronic components in them
that could amplify a
signal. They are basically just a radiator of radio frequency (r.f.)
energy. Now, grant it they are a very special kind of radiator. The
intention being to put
as much of the energy in the best possible area, and to try and
concentrate also on receiving from the best possible area. This area
has to be 360 degrees
around because a yacht can and does move. And you never know which way
you are
going to dock or anchor the vessel. So the antenna has to be able to
cover "all
around."
Vertical Omni-Directional antennas have "Gain" by pulling in the
vertical rf beam width. They gain by concentrating more energy where it
is needed rather than wasting it more up and down where it is not
needed. The gain works in both directions, transmit and receive. Such
antennas are usually compared to a non-gain antenna (either theoretical
"isotropic" or a common "dipole" antennas). In this case comparison is
"dBi" so comparison is to Isotropic. There's a funny PUN on the
dB-whatever used in marketing. The call it "dbM" for db-Marketing. 8 to
9 dB gain in marine wifi or cellular is pretty much standard stuff.
They've got to be careful not to pull the vertical beam width pattern
in Too Much or you could miss the access point (or cell tower as the
case may be) altogether either by under or over shooting it. Antenna
should be placed as high as possible on a yacht... hopefully with
nothing close by on the same height level. Sometimes there are
tradeoffs to get it up there somewhere. But generally you don't want
anything like a large radar or satellite antenna to be in its path.
[That's all for now. If you have any questions on this please contact
me.]
Please contact us for information or for a quote: Telephone Numbers
are: 954-683-3426 mobile, or 954-977-5245.
