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Old September 14th 15, 10:09 PM posted to rec.radio.amateur.homebrew
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Default antenna connected to ground

I think when an antenna has the wrong size it helps to connect
the antenna to the ground and this helps to make the size right -
I think the ground helps to this more flexible

I guess when an antenna is small a lot of charge can get around 1
end and can be bad

I do not know why a big antenna would have a lot of trouble

people talk about adding capacitors and coils to an antenna to
decrease resistance when it has the wrong size - I would like to
know how a coil would change length like a coil may change speed
of electrons as they move toward 1 end

thank you for any answers

Kurt Stocklmeir
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Old September 15th 15, 06:50 PM posted to rec.radio.amateur.homebrew
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Posts: 317
Default antenna connected to ground

In article ,
kurt stocklmeir wrote:

I think when an antenna has the wrong size it helps to connect
the antenna to the ground and this helps to make the size right -
I think the ground helps to this more flexible

I guess when an antenna is small a lot of charge can get around 1
end and can be bad

I do not know why a big antenna would have a lot of trouble

people talk about adding capacitors and coils to an antenna to
decrease resistance when it has the wrong size - I would like to
know how a coil would change length like a coil may change speed
of electrons as they move toward 1 end

thank you for any answers


Kurt-

One common antenna is a HALF WAVE DIPOLE, fed in the center with two
wires. The correct length for a dipole can be determined by dividing
the speed of light by frequency of the radio signal, and dividing that
by two. Simplified, divide 300 by frequency in MegaHertz to get
wavelength in Meters. Divide that by two for length of a half wave
dipole.

Another common antenna is a vertical QUARTER WAVE GROUND PLANE, fed at
the bottom by two wires except one wire is connected to a ground rod or
other buried wires. The ground plane wire is half the length of a
dipole.

What you are asking is more complicated than I can explain here. For
example, the best length is actually slightly shorter than the length
you would calculate. Adding coils and capacitors do not change antenna
length, but make the antenna act as if it were shorter or longer.

You need to study things like the differences between resistance,
impedance and reactance. Also the wires you connect to the antenna are
called a "transmission line", and have their own ideal impedance that
must be matched to the antenna.

73,
Fred
K4DII
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Old September 16th 15, 12:12 AM posted to rec.radio.amateur.homebrew
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First recorded activity by RadioBanter: Apr 2007
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Default antenna connected to ground

On Mon, 14 Sep 2015 21:09:57 +0000, kurt stocklmeir wrote:

I think when an antenna has the wrong size it helps to connect the
antenna to the ground and this helps to make the size right -
I think the ground helps to this more flexible

I guess when an antenna is small a lot of charge can get around 1 end
and can be bad

I do not know why a big antenna would have a lot of trouble

people talk about adding capacitors and coils to an antenna to decrease
resistance when it has the wrong size - I would like to know how a coil
would change length like a coil may change speed of electrons as they
move toward 1 end

thank you for any answers

Kurt Stocklmeir


From the way your post is worded, it sounds like you have been reading
web sites put up by various kooks who say they are experts but really
don't know anything. Get a good antenna theory book from ARRL or some
other good source. That will clear up a lot of your confusion.

--
Jim Mueller

To get my real email address, replace wrongname with dadoheadman.
Then replace nospam with fastmail. Lastly, replace com with us.
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Old September 16th 15, 06:31 AM posted to rec.radio.amateur.homebrew,uk.radio.amateur
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First recorded activity by RadioBanter: Jan 2014
Posts: 329
Default antenna connected to ground

Jim Mueller wrote:
On Mon, 14 Sep 2015 21:09:57 +0000, kurt stocklmeir wrote:

I think when an antenna has the wrong size it helps to connect the
antenna to the ground and this helps to make the size right -
I think the ground helps to this more flexible

I guess when an antenna is small a lot of charge can get around 1 end
and can be bad

I do not know why a big antenna would have a lot of trouble

people talk about adding capacitors and coils to an antenna to decrease
resistance when it has the wrong size - I would like to know how a coil
would change length like a coil may change speed of electrons as they
move toward 1 end

thank you for any answers

Kurt Stocklmeir


From the way your post is worded, it sounds like you have been reading
web sites put up by various kooks who say they are experts but really
don't know anything.


Gareth Alun Evans G4SDW has a website?

--
STC // M0TEY // twitter.com/ukradioamateur
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