Hi my name is Don and I primarily design and test antennas for a living
and I'm here today to try to explain to you
basically a little bit about how antennas work
so the first thing I want to start with is the antenna wire and we call it coaxial cable
so the first thing we are going to talk about it what is not coaxial cable
this is just normal power cable notice that the lines are parallel to each other
this coaxial cable you'll notice that there's a shield on the outside and then
there's an insulator and then there's a center conductor, the center conductor is
actually what runs the power to the antenna. The reason this is important is
how an internal works. So if you have two pieces of wire side-by-side, you have
current flow in this direction and current flow in that direction the
current flows cancel each other out if you have a piece of coaxial cable
this is actually grounded on the outside and the current flows in this direction and the
current flows in that direction on the inside and the currents cancel each other out
how we gettin intended to work and actually radiate power is to change that
so to change that we want to transmit power out to the air so once again you
have two pieces of wired and you have current flow in this direction and
current flow in that direction
a simple dipole antenna like you put on your FM stereo at home is just when you
take this wire and split off over in this direction and split it off over this direction
and now I still have current flow in this direction and I still have
current flow in this direction but if you notice the current flows in the same
direction across this plane and that allows us to generate RF energy that
leaves like this, and can be received as well. So if you have two pieces of wire
side-by-side the electromagnetic energy
that is generated from current flow cancel each other out so if I have a wire
here and have a wire here, this one we'll call it positive and this one we'll call
negative because this was positive in this one's negative you can't get any
energy to radiate out because they cancel each other out I think that's
pretty simple but if I take and I separate these two wires like this so
this is still my feed point down here and I have current flow in this direction
and in this direction and I have current flow in this direction and in this
direction but every time you have current flow you also have electromagnetic
energy so now because I have current flow in the same direction across this
plane now I have an energy field that looks like this. I have a high current
point here and a low current point here but high voltage point here and when
that high voltage point hits they're all that electromagnetic energy jumps off
the wire and radiates out into space that's basically how an antenna works,
most antennas act very similar to a dipole antenna and that's what this is and
remember a dipole antenna you have radiated energy on both sides
How does an antenna receive energy? Well like on a cell tower a cell tower is
radiating energy just like our antenna here was radiating energy out, well
radiated energy also can be received by this same antenna so the antenna
captures that energy and then transfers it down to our feed point so we can run
into an amplifier or maybe you just plug it straight into your stereo system or
on a car stereo you plug it into the back of the car stereo and they all act
very similarly. I hope everything that I've explained today was apparent and
you understood it and if you have any questions or comments please feel free
to leave that and please subscribe to our channel we will be releasing more
videos in the future. Have a great day.