Dipole connected to grounded receiver?
 

I have one question about dipole connected to grounded receiver.

I've made dipole antenna. One "pole" is connected to center line of coax,
the other to shield line of the coax. Cable goes down to receiver and
connects with BNC. The BNC is (of course) connected to case. The case is
grounded.

Can someone tell me, what is te purpose of the dipole if one of the poles is
grounded? I mean, why i built two poles when one goes directly to
ground!Shouldn't it be easier to build just a monopole? I'm puzzled....

Thanks in advance
tom

Can someone tell me, what is te purpose of the dipole if one of the poles is
grounded? I mean, why i built two poles when one goes directly to
ground!Shouldn't it be easier to build just a monopole? I'm puzzled....

Thanks in advance
tom




Answer lies in the fact that any piece of wire, depending on its (electrical)
length in terms of wavelength is not anymore just "shorting" conductor. It is
an antenna, feedline or anything in between, definitely not just DC current
"grounding wire".
The other "pole" has the important function too, but that is another antenna
story.

Yuri

Tom,

The dipole is a balanced antenna, fed at the center. Stricly speaking, you
should be using a 1:1 balun to connect to an unbalanced feedline. However,
no great harm comes if you just connect it to the coax directly. DO NOT use
a standard TV/FM balun, they are 4:1, and you are better off with it just
like it is.

Tam/WB2TT
"Tom" wrote in message
...
I have one question about dipole connected to grounded receiver.

I've made dipole antenna. One "pole" is connected to center line of coax,
the other to shield line of the coax. Cable goes down to receiver and
connects with BNC. The BNC is (of course) connected to case. The case is
grounded.

Can someone tell me, what is te purpose of the dipole if one of the poles
is
grounded? I mean, why i built two poles when one goes directly to
ground!Shouldn't it be easier to build just a monopole? I'm puzzled....

Thanks in advance
tom

Thank you for the solution to a problem I did not
realize I had. One of the pleasures of QRP is low
power levels. One of the ways to get a greater
bandwidth from a dipole is to make it a folded
dipole. A great way to feed a folded dipole would
be with a "TV" balun.

--
73 es cul

wb3fup
a Salty Bear

"Tarmo Tammaru" wrote in
message ...
Tom,

The dipole is a balanced antenna, fed at the
center. Stricly speaking, you
should be using a 1:1 balun to connect to an
unbalanced feedline. However,
no great harm comes if you just connect it to
the coax directly. DO NOT use
a standard TV/FM balun, they are 4:1, and you
are better off with it just
like it is.

Tam/WB2TT
"Tom" wrote in message
...
I have one question about dipole connected to
grounded receiver.

I've made dipole antenna. One "pole" is
connected to center line of coax,
the other to shield line of the coax. Cable
goes down to receiver and
connects with BNC. The BNC is (of course)
connected to case. The case is
grounded.

Can someone tell me, what is te purpose of the
dipole if one of the poles
is
grounded? I mean, why i built two poles when
one goes directly to
ground!Shouldn't it be easier to build just a
monopole? I'm puzzled....

Thanks in advance
tom

W7TI wrote:
It just happens to be grounded for convenience, because the circuitry in
the radio is grounded and making the connection between antenna and
radio is easier. Strictly speaking, we shouldn't be using the word
"grounded" here, but rather we should refer to a common connection.
Neither the antenna nor the radio has to be connected to an actual earth
ground to work.

Well actually my story is a little bit different. I've spent 1 and half hour
diging the hole and beating the pipe with the sledge hammer for another 2
hours in front of my building while listening my neighbours complaining....
all that just to finally have a good grounding.

Connected the ground to my receiver and realized that from now on my dipole
is no longer "floating". One of its ends is now directly grounded through
the BNC connection on the case.

So now i would just like to know can i disconnect one of the poles from my
dipole and use monopole? Is maybe the trick in capacity between two
poles? Is that the reason why i can't remove one pole?

Thanks in advance....
tom