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Antenna and its types

Site.ANTENNAANDITSTYPES History

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October 03, 2014, at 08:52 AM EST by Rathnasree -
Changed lines 1-85 from:

O4gSd1? , [url=http://bglvjropcuii.com/]bglvjropcuii[/url], [link=http://agvjbhfweibp.com/]agvjbhfweibp[/link], http://giztudykxijt.com/

to:

(:title Antenna and its types :)


Basic Consideration
The study of antennas must include a quick review of impedance matching and rasonant circuits.Maximum Power transfer could be achieved when source matches the load.This is maximum power transfer Theorm.For eg : In radio jove the transmission cable used is of 75 Ohms in order to match the impedance of 73 ohms at feed.I will be talking of calculation of impedance at feed later.

Material of antenna
An antenna is a structure that is generally a metallic object often a wire used to convert high frequency current into electromagnetic waves or vice versa.

RADIO JOVE uses a dipole antenna which is made up of copper wire.Even a single piece of wire acts as an antenna.We can simply try to listening disturbances at SW receiver using a long piece of wire wrap with aluminium foil.

DIPOLE ANTENNA FOR RADIO TELESCOPE
1) Theoretical Length of Antenna
2)Exact Length
3)Height of Antenna
4)Transmission Line
5)Impedance
6)Velocity factor
7)Dual Dipole Configrations
8)Components in Antenna System
I will be discussing all the above mentioned points for a dipole antenna one by one.

THEORETICAL LENGTH OF ANTENNA


One of the simplest antenna is called a dipole antenna. It can be made from two pieces of copper wire and three insulators. A radio wave is an electromagnetic wave travelling in the space at the speed of light. The frequency of the wave is the number of cycles that occurred each second, and the wavelength is the distance that the wave travels during one cycle. The frequency (f), wavelength and speed of light are related by the simple equation:

                     Wavelength = speed of light/frequency


For Radio Jove we chose 20.1mhz as our antenna operating frequency after considering the fact that the bursts occurring in the outer celestial bodies( eg all planets) emits radio waves broadly on all frequencies but till 15mhz all radio waves get absorbed by the ionosphere layer in our atmosphere and it start coming on earth from 18mhz but its maximum strength is inbetween 20 to 20.4mhz, so we decided to have 20.1mhz as our centered operating frequency. The free space wavelength is therefore:-
                       Wavelength=3x108/20.1x106= 14.925meters      


                                Wavelength= 14.925meters                                  

Now, For dipole antenna Length of antenna is given by
Length= Wavelength/2= 14.925/2= 7.46meters= 24.46feet

Length of dipole antenna to be used at 20.1 Mhz comes out to be 24.46 feets.


"Diagrammatic Representation of Theoretical Antenna Length"
http://img689.imageshack.us/img689/1446/antenna1.png

                           Dipole Antenna(Theoretical Length)


EXACT LENGTH OF ANTENNA
By above analysis we find the length of dipole antenna to be 24.46 feets.But antenna length is taken to be 95% of Theoretical length.
Why antenna length is taken to be 95% of theoretical length?
Energy travels slowly in solid than in air.Current at the end of rod does not have space to move freely as center of antenna.So ends exhibit capacitive effect.This effect is offset by making antenna size smaller than normal size.

Exact antenna length=95% of Theoretical Length

Exact length=24.46*0.95=23.28 feet.

Length of copper wire to be used for antenna construction is 23.28 feet. http://img62.imageshack.us/img62/8871/antenna2.jpg

                     Dipole antenna(Exact length)
October 20, 2012, at 11:05 AM EST by yekyhytz - 111
Changed line 1 from:

sM58Rf <a href="http://orqmgxswwehi.com/">orqmgxswwehi</a>

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O4gSd1? , [url=http://bglvjropcuii.com/]bglvjropcuii[/url], [link=http://agvjbhfweibp.com/]agvjbhfweibp[/link], http://giztudykxijt.com/

October 20, 2012, at 05:22 AM EST by lbqhtkemdes - 111
Changed line 1 from:

ciUh12 , [url=http://fxzlubgwegkr.com/]fxzlubgwegkr[/url], [link=http://edziabuekjfu.com/]edziabuekjfu[/link], http://nppfrvjrjtvg.com/

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sM58Rf <a href="http://orqmgxswwehi.com/">orqmgxswwehi</a>

October 19, 2012, at 11:03 PM EST by rfcquceb - 111
Changed line 1 from:

4.0 out of 5 stars Review ChannelMaster? 4228HD and a 2 Antenna Solution My house is in Mountain View, in the San Francisco Bay Area, 32 miles south from most San Francisco stations, and 14 miles nothwrest from some desirable stations in San Jose.

to:

ciUh12 , [url=http://fxzlubgwegkr.com/]fxzlubgwegkr[/url], [link=http://edziabuekjfu.com/]edziabuekjfu[/link], http://nppfrvjrjtvg.com/

October 19, 2012, at 05:38 AM EST by Fieka - 111
Changed line 1 from:

OBXvYB? <a href="http://eaxvfxnxcvhf.com/">eaxvfxnxcvhf</a>

to:

4.0 out of 5 stars Review ChannelMaster? 4228HD and a 2 Antenna Solution My house is in Mountain View, in the San Francisco Bay Area, 32 miles south from most San Francisco stations, and 14 miles nothwrest from some desirable stations in San Jose.

October 17, 2012, at 03:01 AM EST by kbuowi - 111
Changed line 1 from:

If you're looking to buy these articles make it way easeir.

to:

OBXvYB? <a href="http://eaxvfxnxcvhf.com/">eaxvfxnxcvhf</a>

October 16, 2012, at 07:15 PM EST by Kelli - ByUkARbUjiuKHBofK
Changed line 1 from:

When my son was younger, I used to tell him, "Listen to me with your whole body." At the time, I didn't know he had ADD, but I knew he was esaliy distracted. Using my eyes to hear God--maybe that's the cure to my spiritual ADD?

to:

If you're looking to buy these articles make it way easeir.

October 16, 2012, at 03:35 PM EST by Syah - 111
Changed line 1 from:

Hi Wayne! Thanks for the comment! Nice to meet antheor fellow Ham who can relate to my antenna problems! I'm sorry that you lost your antenna, but I'm glad you and your family are all right! Tornado's and antennas definitely don't mix! I finally have rigged something up to get back on HF AND I'll be posting all about it shortly! It's great to be able to twirl that dial once again! Take care, Suzanne N1SUZ?

to:

When my son was younger, I used to tell him, "Listen to me with your whole body." At the time, I didn't know he had ADD, but I knew he was esaliy distracted. Using my eyes to hear God--maybe that's the cure to my spiritual ADD?

October 16, 2012, at 02:39 PM EST by Jason - 111
Changed lines 1-85 from:

(:title Antenna and its types :)


Basic Consideration
The study of antennas must include a quick review of impedance matching and rasonant circuits.Maximum Power transfer could be achieved when source matches the load.This is maximum power transfer Theorm.For eg : In radio jove the transmission cable used is of 75 Ohms in order to match the impedance of 73 ohms at feed.I will be talking of calculation of impedance at feed later.

Material of antenna
An antenna is a structure that is generally a metallic object often a wire used to convert high frequency current into electromagnetic waves or vice versa.

RADIO JOVE uses a dipole antenna which is made up of copper wire.Even a single piece of wire acts as an antenna.We can simply try to listening disturbances at SW receiver using a long piece of wire wrap with aluminium foil.

DIPOLE ANTENNA FOR RADIO TELESCOPE
1) Theoretical Length of Antenna
2)Exact Length
3)Height of Antenna
4)Transmission Line
5)Impedance
6)Velocity factor
7)Dual Dipole Configrations
8)Components in Antenna System
I will be discussing all the above mentioned points for a dipole antenna one by one.

THEORETICAL LENGTH OF ANTENNA


One of the simplest antenna is called a dipole antenna. It can be made from two pieces of copper wire and three insulators. A radio wave is an electromagnetic wave travelling in the space at the speed of light. The frequency of the wave is the number of cycles that occurred each second, and the wavelength is the distance that the wave travels during one cycle. The frequency (f), wavelength and speed of light are related by the simple equation:

                     Wavelength = speed of light/frequency


For Radio Jove we chose 20.1mhz as our antenna operating frequency after considering the fact that the bursts occurring in the outer celestial bodies( eg all planets) emits radio waves broadly on all frequencies but till 15mhz all radio waves get absorbed by the ionosphere layer in our atmosphere and it start coming on earth from 18mhz but its maximum strength is inbetween 20 to 20.4mhz, so we decided to have 20.1mhz as our centered operating frequency. The free space wavelength is therefore:-
                       Wavelength=3x108/20.1x106= 14.925meters      


                                Wavelength= 14.925meters                                  

Now, For dipole antenna Length of antenna is given by
Length= Wavelength/2= 14.925/2= 7.46meters= 24.46feet

Length of dipole antenna to be used at 20.1 Mhz comes out to be 24.46 feets.


"Diagrammatic Representation of Theoretical Antenna Length"
http://img689.imageshack.us/img689/1446/antenna1.png

                           Dipole Antenna(Theoretical Length)


EXACT LENGTH OF ANTENNA
By above analysis we find the length of dipole antenna to be 24.46 feets.But antenna length is taken to be 95% of Theoretical length.
Why antenna length is taken to be 95% of theoretical length?
Energy travels slowly in solid than in air.Current at the end of rod does not have space to move freely as center of antenna.So ends exhibit capacitive effect.This effect is offset by making antenna size smaller than normal size.

Exact antenna length=95% of Theoretical Length

Exact length=24.46*0.95=23.28 feet.

Length of copper wire to be used for antenna construction is 23.28 feet. http://img62.imageshack.us/img62/8871/antenna2.jpg

                     Dipole antenna(Exact length)
to:

Hi Wayne! Thanks for the comment! Nice to meet antheor fellow Ham who can relate to my antenna problems! I'm sorry that you lost your antenna, but I'm glad you and your family are all right! Tornado's and antennas definitely don't mix! I finally have rigged something up to get back on HF AND I'll be posting all about it shortly! It's great to be able to twirl that dial once again! Take care, Suzanne N1SUZ?

April 22, 2010, at 01:25 AM EST by 59.177.2.217 -
March 10, 2010, at 10:21 AM EST by 59.180.220.185 -
Added lines 79-82:

http://img62.imageshack.us/img62/8871/antenna2.jpg

                     Dipole antenna(Exact length)
March 10, 2010, at 10:17 AM EST by 59.180.220.185 -
Added line 67:


March 10, 2010, at 10:15 AM EST by 59.180.220.185 -
Changed lines 64-79 from:

Dipole Antenna(Theoretical Length)

to:
                           Dipole Antenna(Theoretical Length)


EXACT LENGTH OF ANTENNA By above analysis we find the length of dipole antenna to be 24.46 feets.But antenna length is taken to be 95% of Theoretical length.
Why antenna length is taken to be 95% of theoretical length?
Energy travels slowly in solid than in air.Current at the end of rod does not have space to move freely as center of antenna.So ends exhibit capacitive effect.This effect is offset by making antenna size smaller than normal size.

Exact antenna length=95% of Theoretical Length

Exact length=24.46*0.95=23.28 feet.

Length of copper wire to be used for antenna construction is 23.28 feet.

March 10, 2010, at 09:54 AM EST by 59.180.220.185 -
Changed line 62 from:

http://img689.imageshack.us/img689/1446/antenna1.png

to:

http://img689.imageshack.us/img689/1446/antenna1.png

Changed line 64 from:
               Dipole Antenna(Theoretical Length)
to:

Dipole Antenna(Theoretical Length)

March 09, 2010, at 09:22 AM EST by 59.177.8.235 -
Changed line 4 from:

Basic Consideration

to:

Basic Consideration

Changed line 8 from:

Material of antenna

to:

Material of antenna

Changed line 15 from:

DIPOLE ANTENNA FOR RADIO TELESCOPE

to:

DIPOLE ANTENNA FOR RADIO TELESCOPE

March 09, 2010, at 09:19 AM EST by 59.177.8.235 -
Changed line 64 from:

Dipole Antenna(Theoretical Length)

to:
               Dipole Antenna(Theoretical Length)
March 09, 2010, at 09:18 AM EST by 59.177.8.235 -
Changed lines 62-64 from:

http://img689.imageshack.us/img689/1446/antenna1.pngDipole Antenna

to:

http://img689.imageshack.us/img689/1446/antenna1.png
Dipole Antenna(Theoretical Length)

March 09, 2010, at 09:17 AM EST by 59.177.8.235 -
Changed lines 61-62 from:

http://img689.imageshack.us/i/antenna1.png/"Dipole Antenna"

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http://img689.imageshack.us/img689/1446/antenna1.pngDipole Antenna

March 09, 2010, at 09:13 AM EST by 59.177.8.235 -
Changed lines 57-62 from:

Length of dipole antenna to be used at 20.1 Mhz comes out to be 24.46 feets

to:

Length of dipole antenna to be used at 20.1 Mhz comes out to be 24.46 feets.


"Diagrammatic Representation of Theoretical Antenna Length" http://img689.imageshack.us/i/antenna1.png/"Dipole Antenna"

March 09, 2010, at 08:52 AM EST by 59.177.8.235 -
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March 09, 2010, at 08:51 AM EST by 59.177.8.235 -
Added line 55:
March 09, 2010, at 08:50 AM EST by 59.177.8.235 -
Changed lines 44-45 from:

For Radio Jove we chose 20.1mhz as our antenna operating frequency after considering the fact that the bursts occurring in the outer celestial bodies( eg all planets) emits radio waves broadly on all frequencies but till 15mhz all radio waves get absorbed by the ionosphere layer in our atmosphere and it start coming on earth from 18mhz but its maximum strength is inbetween 20 to 20.4mhz, so we decided to have 20.1mhz as our centered operating frequency. The free space wavelength is therefore:-

to:
For Radio Jove we chose 20.1mhz as our antenna operating frequency after considering the fact that the bursts occurring in the outer celestial bodies( eg all planets) emits radio waves broadly on all frequencies but till 15mhz all radio waves get absorbed by the ionosphere layer in our atmosphere and it start coming on earth from 18mhz but its maximum strength is inbetween 20 to 20.4mhz, so we decided to have 20.1mhz as our centered operating frequency. The free space wavelength is therefore:-
Changed line 48 from:

\\

to:
Changed line 51 from:
      Now, For dipole antenna 
to:

Now, For dipole antenna

March 09, 2010, at 08:48 AM EST by 59.177.8.235 -
Changed line 42 from:
                     Wavelength=speed of light/frequency
to:
                     Wavelength = speed of light/frequency
Changed line 46 from:
                       Wavelength=3x108/20.1x106= 14.925meters      
to:
                       Wavelength=3x108/20.1x106= 14.925meters      
Changed line 49 from:
                                Wavelength= 14.925meters                                  
to:
                                Wavelength= 14.925meters                                  
Changed lines 53-54 from:
                                Wavelength/2= 14.925/2= 7.46meters=24.46feet
to:
                               Length= Wavelength/2= 14.925/2= 7.46meters= 24.46feet

Length of dipole antenna to be used at 20.1 Mhz comes out to be 24.46 feets

March 09, 2010, at 08:46 AM EST by 59.177.8.235 -
Deleted line 0:
Added line 19:
Added lines 33-53:


I will be discussing all the above mentioned points for a dipole antenna one by one.

THEORETICAL LENGTH OF ANTENNA


One of the simplest antenna is called a dipole antenna. It can be made from two pieces of copper wire and three insulators. A radio wave is an electromagnetic wave travelling in the space at the speed of light. The frequency of the wave is the number of cycles that occurred each second, and the wavelength is the distance that the wave travels during one cycle. The frequency (f), wavelength and speed of light are related by the simple equation:

                     Wavelength=speed of light/frequency


For Radio Jove we chose 20.1mhz as our antenna operating frequency after considering the fact that the bursts occurring in the outer celestial bodies( eg all planets) emits radio waves broadly on all frequencies but till 15mhz all radio waves get absorbed by the ionosphere layer in our atmosphere and it start coming on earth from 18mhz but its maximum strength is inbetween 20 to 20.4mhz, so we decided to have 20.1mhz as our centered operating frequency. The free space wavelength is therefore:-

                       Wavelength=3x108/20.1x106= 14.925meters      

\\

                                Wavelength= 14.925meters                                  
      Now, For dipole antenna 

Length of antenna is given by
Wavelength/2= 14.925/2= 7.46meters=24.46feet

March 06, 2010, at 08:23 AM EST by Rathnasree -
Added lines 1-32:

(:title Antenna and its types :)


Basic Consideration
The study of antennas must include a quick review of impedance matching and rasonant circuits.Maximum Power transfer could be achieved when source matches the load.This is maximum power transfer Theorm.For eg : In radio jove the transmission cable used is of 75 Ohms in order to match the impedance of 73 ohms at feed.I will be talking of calculation of impedance at feed later.

Material of antenna
An antenna is a structure that is generally a metallic object often a wire used to convert high frequency current into electromagnetic waves or vice versa.

RADIO JOVE uses a dipole antenna which is made up of copper wire.Even a single piece of wire acts as an antenna.We can simply try to listening disturbances at SW receiver using a long piece of wire wrap with aluminium foil.

DIPOLE ANTENNA FOR RADIO TELESCOPE
1) Theoretical Length of Antenna
2)Exact Length
3)Height of Antenna
4)Transmission Line
5)Impedance
6)Velocity factor
7)Dual Dipole Configrations
8)Components in Antenna System

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Page last modified on October 03, 2014, at 08:52 AM EST