Antenna Power Divider
This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA
Overview
Download & View Antenna Power Divider as PDF for free.
More details
- Words: 1,240
- Pages: 2
RBS FM 92.60 MHz the Best Radio Station in Tulungagung - Power Divid...
1 of 2
http://rbsfm.ej.am/joomla/index.php?option=com_content&task=view&id...
search...
Search Amazon.com:
Keywords:
R B S Welcome to RBS FM F M T u l u n g a g u n g
The Real Community Radio in Tulungagung
Main Menu Home News Blog Generals Researches Schematics Antennas Downloads
Latest News
Popular
Push-Pull versus Balanced RF Amplifier Standard American Wire Gauge Data for Bare Copper My Favourite VST For FM Audio Processor Turn Your Audio Editing Software Into Powerful Live Audio Processor Digital Stereo Encoder Simulation Power Divider for Stacking 2 Bays or 4 Bays Antenna SONOS - MBL4 Preset/Format Files LM383 7W or 16W Audio Power Amplifier Applications LM221 and LM321 Preamplifier Applications LM4882 - 250mW Boomer Audio Power Amplifier with Shutdown Mode
FM Radio Stations in Indonesia PLL Transmitter and Stereo Encoder PLL Transmitter 88-108 MHz 500 Watt Audio Power Amplifier 300 Watt Broadband Amplifier TV Modulator (Exiter) with MC1374 Transmitter FM 88-108 MHz Zara Radio PLL KIT with TC9122, TC5081, TC 5082 Airomate (Stereo Coder + RDS)
Links Search
Home
Antennas
Matching Sections
Power Divider for Stacking 2 Bays or 4 Bays Antenna
Forum
Power Divider for Stacking 2 Bays or 4 Bays Antenna
Guestbook
Written by BuSan Sunday, 04 November 2007
Contact Us RBS Crew About Us
Related Items
One of the ways to improve the over all performance of any radio station is to put up bigger antennas. Antenna improvements affect both the transmitted and received signal and thus increase your operating range. Once you reach a certain point, the only practical way to get "bigger" antennas is to put up multiple antennas phased in such a way so that the total gain of the array increases (hopefully). For VHF and above this usually requires the ubiquitous power divider. Over the years I have built power dividers using coaxial cable or round copper tubing to achieve the necessary matching of the various antennas in an array. Recently, I have been using waveguide to construct 2 and 4 way power dividers. The waveguide has the advantage of being rectangular which greatly facilitates the attachment of the coaxial cable connectors. It is also made of copper, unlike power dividers made of square or rectangular aluminum tubing, which means the whole assembly can be soldered for long lasting, waterproof, electrical connections.
Coaxial Dipole, Loaded Dipole and Quagi-uda Antenna Vertical, Quagi and Discone Antenna Log Periodic Broadband Antenna Antenna Principles Demokratisasi Pemancar Radio 6 dB Colinear VHF
The Theory A few words on how power dividers work is in order. Once you understand the simple theory of operation of a power divider (combiner also) then you may come up with another way of building 1/4 lambda transmission line transformers that better suits your needs or available materials list. The basic objective is to build transmission lines with the proper characteristic impedance to match two different RF impedances. The shape or size of the transmission line doesn't matter as long as it is the right impedance. The two most common configurations are intended to combine either 2 or 4 antennas, each with a nominal impedance of 50 ohms. If you were to merely connect 2 antennas with equal lengths of 50-ohm cable together the resulting impedance at the joined ends would be 25 ohms. This really isn't too bad, but we can do better. If we could somehow "transform" the 50 ohms at the end of each cable to 100 ohms, then when we joined the new ends together we would be back to 50 ohms (The impedances combine like resistors in parallel).
Antenna. Circularly-Polarized Antenna Quad Antenna Super J-Pole Antenna Skyhopper and Parabolic Antenna Capacitors, Gamma Match and Feedline Discone - VHF to UHF Broadband Antenna
Figure 1. Quarter Wave Transformer Such an impedance transforming device is an electrical 1/4 lambda (compensated for the velocity factor of the transmission line at the frequency of interest) piece of transmission line having a characteristic impedance (Z0) determined by the following equation:
Z0=Square Root ( Z1 x Z2) With Z1=Input Impedance, Z2=Output Impedance (Figure 1 .) In the above example we want to take the 50 ohms at the end of the cable and 'step it up' to 100 ohms. The formula predicts that if the 1/4 lambda transmission line impedance is 70.7 ohms from [Sq. Rt. (50x100)], then we will achieve the desired impedance transformation (See diagram below). This 'transformer' effect also works with any odd number of quarter wavelengths (i.e. 3/4 lambda, 5/4 lambda, 7/4 lambda, etc.). Aha! So this is why we used RG-11 (75 ohms) to match two antennas in the good old days. The trick was to get the RG-11 the right length (Odd number of electrical quarter wavelengths). In this case the whole piece of RG-11 was the transformer. If a power divider is being used then the only requirement is that all the 50 ohm 'phasing' lines have to be the same length, any length, but all the same. Much easier! Figure 2 . is an impedance diagram for matching two antennas.
Figure 2. Two Way Power Divider In the case of 4 antennas, if we connect two of the antenna feeds together (parallel) with equal lengths of 50-ohm cable then the impedance at this point is 25 ohms. The transformer has to then step up this 25-ohm load to 100 ohms. Thus when we connect the transformed 100 ohms from the other two antennas, the resulting impedance at the center will be back to 50 ohms (See Figure 3 .). From the formula above the transformers required must have a characteristic of impedance of 50 ohms. Once again this could all be done with coaxial cables of the proper length, but it is much easier with a power divider.
10/17/2008 4:32 PM
RBS FM 92.60 MHz the Best Radio Station in Tulungagung - Power Divid...
2 of 2
http://rbsfm.ej.am/joomla/index.php?option=com_content&task=view&id...
Figure 3. Four Way Power Divider What is described here is just one way of building power dividers. There are other configurations such as having two or four antennas connected to one end of a power divider and use a single 1/4 lambda transformer to step up to 50 ohms. The theory is the same for all cases, just different numbers. I think you will find the construction of the actual device is easier in the configurations described here.
Real Power Divider I make mine with 1 inch (25.4 mm OD) square section tube ("D"); it has 2 mm wall thickness, and a round centre conductor, using the formula:
Z0 =138log{1.08*D/d} With Z0 = impedance λ/4 line (70.7 Ω for two way or 50 Ω for four way) D = inside dimension of outer conductor (23.4 mm ID) d = outside diameter of inner conductor (7.9 mm OD for two way or 11 mm OD for four way) ID = Inner Diameter OD = Outer Diameter Now all you need to do is calculating the length of λ/4 transmission line transformers that frequency dependent!!!
Powered By :
Figure 4. Two Way Power Divider
Figure 5. Four Way Power Divider
Next > [ Back ]
Login Form
Syndicate
Who's Online
Template Chooser
We have 1 guest online
Username Password
Remember me my_radio1
Login
Select
Lost Password?
No account yet? Register Top Home
Term of Use
Privacy Policy
© 2008 RBS FM 92.60 MHz the Best Radio Station in Tulungagung. All rights reserved. Powered By Joomla!
10/17/2008 4:32 PM
1 of 2
http://rbsfm.ej.am/joomla/index.php?option=com_content&task=view&id...
search...
Search Amazon.com:
Keywords:
R B S Welcome to RBS FM F M T u l u n g a g u n g
The Real Community Radio in Tulungagung
Main Menu Home News Blog Generals Researches Schematics Antennas Downloads
Latest News
Popular
Push-Pull versus Balanced RF Amplifier Standard American Wire Gauge Data for Bare Copper My Favourite VST For FM Audio Processor Turn Your Audio Editing Software Into Powerful Live Audio Processor Digital Stereo Encoder Simulation Power Divider for Stacking 2 Bays or 4 Bays Antenna SONOS - MBL4 Preset/Format Files LM383 7W or 16W Audio Power Amplifier Applications LM221 and LM321 Preamplifier Applications LM4882 - 250mW Boomer Audio Power Amplifier with Shutdown Mode
FM Radio Stations in Indonesia PLL Transmitter and Stereo Encoder PLL Transmitter 88-108 MHz 500 Watt Audio Power Amplifier 300 Watt Broadband Amplifier TV Modulator (Exiter) with MC1374 Transmitter FM 88-108 MHz Zara Radio PLL KIT with TC9122, TC5081, TC 5082 Airomate (Stereo Coder + RDS)
Links Search
Home
Antennas
Matching Sections
Power Divider for Stacking 2 Bays or 4 Bays Antenna
Forum
Power Divider for Stacking 2 Bays or 4 Bays Antenna
Guestbook
Written by BuSan Sunday, 04 November 2007
Contact Us RBS Crew About Us
Related Items
One of the ways to improve the over all performance of any radio station is to put up bigger antennas. Antenna improvements affect both the transmitted and received signal and thus increase your operating range. Once you reach a certain point, the only practical way to get "bigger" antennas is to put up multiple antennas phased in such a way so that the total gain of the array increases (hopefully). For VHF and above this usually requires the ubiquitous power divider. Over the years I have built power dividers using coaxial cable or round copper tubing to achieve the necessary matching of the various antennas in an array. Recently, I have been using waveguide to construct 2 and 4 way power dividers. The waveguide has the advantage of being rectangular which greatly facilitates the attachment of the coaxial cable connectors. It is also made of copper, unlike power dividers made of square or rectangular aluminum tubing, which means the whole assembly can be soldered for long lasting, waterproof, electrical connections.
Coaxial Dipole, Loaded Dipole and Quagi-uda Antenna Vertical, Quagi and Discone Antenna Log Periodic Broadband Antenna Antenna Principles Demokratisasi Pemancar Radio 6 dB Colinear VHF
The Theory A few words on how power dividers work is in order. Once you understand the simple theory of operation of a power divider (combiner also) then you may come up with another way of building 1/4 lambda transmission line transformers that better suits your needs or available materials list. The basic objective is to build transmission lines with the proper characteristic impedance to match two different RF impedances. The shape or size of the transmission line doesn't matter as long as it is the right impedance. The two most common configurations are intended to combine either 2 or 4 antennas, each with a nominal impedance of 50 ohms. If you were to merely connect 2 antennas with equal lengths of 50-ohm cable together the resulting impedance at the joined ends would be 25 ohms. This really isn't too bad, but we can do better. If we could somehow "transform" the 50 ohms at the end of each cable to 100 ohms, then when we joined the new ends together we would be back to 50 ohms (The impedances combine like resistors in parallel).
Antenna. Circularly-Polarized Antenna Quad Antenna Super J-Pole Antenna Skyhopper and Parabolic Antenna Capacitors, Gamma Match and Feedline Discone - VHF to UHF Broadband Antenna
Figure 1. Quarter Wave Transformer Such an impedance transforming device is an electrical 1/4 lambda (compensated for the velocity factor of the transmission line at the frequency of interest) piece of transmission line having a characteristic impedance (Z0) determined by the following equation:
Z0=Square Root ( Z1 x Z2) With Z1=Input Impedance, Z2=Output Impedance (Figure 1 .) In the above example we want to take the 50 ohms at the end of the cable and 'step it up' to 100 ohms. The formula predicts that if the 1/4 lambda transmission line impedance is 70.7 ohms from [Sq. Rt. (50x100)], then we will achieve the desired impedance transformation (See diagram below). This 'transformer' effect also works with any odd number of quarter wavelengths (i.e. 3/4 lambda, 5/4 lambda, 7/4 lambda, etc.). Aha! So this is why we used RG-11 (75 ohms) to match two antennas in the good old days. The trick was to get the RG-11 the right length (Odd number of electrical quarter wavelengths). In this case the whole piece of RG-11 was the transformer. If a power divider is being used then the only requirement is that all the 50 ohm 'phasing' lines have to be the same length, any length, but all the same. Much easier! Figure 2 . is an impedance diagram for matching two antennas.
Figure 2. Two Way Power Divider In the case of 4 antennas, if we connect two of the antenna feeds together (parallel) with equal lengths of 50-ohm cable then the impedance at this point is 25 ohms. The transformer has to then step up this 25-ohm load to 100 ohms. Thus when we connect the transformed 100 ohms from the other two antennas, the resulting impedance at the center will be back to 50 ohms (See Figure 3 .). From the formula above the transformers required must have a characteristic of impedance of 50 ohms. Once again this could all be done with coaxial cables of the proper length, but it is much easier with a power divider.
10/17/2008 4:32 PM
RBS FM 92.60 MHz the Best Radio Station in Tulungagung - Power Divid...
2 of 2
http://rbsfm.ej.am/joomla/index.php?option=com_content&task=view&id...
Figure 3. Four Way Power Divider What is described here is just one way of building power dividers. There are other configurations such as having two or four antennas connected to one end of a power divider and use a single 1/4 lambda transformer to step up to 50 ohms. The theory is the same for all cases, just different numbers. I think you will find the construction of the actual device is easier in the configurations described here.
Real Power Divider I make mine with 1 inch (25.4 mm OD) square section tube ("D"); it has 2 mm wall thickness, and a round centre conductor, using the formula:
Z0 =138log{1.08*D/d} With Z0 = impedance λ/4 line (70.7 Ω for two way or 50 Ω for four way) D = inside dimension of outer conductor (23.4 mm ID) d = outside diameter of inner conductor (7.9 mm OD for two way or 11 mm OD for four way) ID = Inner Diameter OD = Outer Diameter Now all you need to do is calculating the length of λ/4 transmission line transformers that frequency dependent!!!
Powered By :
Figure 4. Two Way Power Divider
Figure 5. Four Way Power Divider
Next > [ Back ]
Login Form
Syndicate
Who's Online
Template Chooser
We have 1 guest online
Username Password
Remember me my_radio1
Login
Select
Lost Password?
No account yet? Register Top Home
Term of Use
Privacy Policy
© 2008 RBS FM 92.60 MHz the Best Radio Station in Tulungagung. All rights reserved. Powered By Joomla!
10/17/2008 4:32 PM
Related Documents
Antenna Power Divider
November 2019 26
Rf Antenna Power Dividers
November 2019 24
Antenna
June 2020 21
Antenna
June 2020 14
Cdma Power Control, Smart Antenna
June 2020 7
Divider Months.docx
November 2019 16More Documents from "Verasenan Gunasekaran"
S Parameters An 95 1
November 2019 13
Smith Chart
November 2019 14
2 Meter Slim Jim Copper Tubing Antenna By Ke5fxu
November 2019 16
Slotted-cylinder Antennas References
November 2019 11
Notes On The Batwing 3
November 2019 15