.net barcode reader component download Vertically polarized HF antennas in Software

Creating Data Matrix 2d barcode in Software Vertically polarized HF antennas

196 Vertically polarized HF antennas
Recognizing Data Matrix In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Data Matrix Creation In None
Using Barcode drawer for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
Radiator element
Data Matrix 2d Barcode Recognizer In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
Data Matrix ECC200 Printer In Visual C#.NET
Using Barcode printer for VS .NET Control to generate, create Data Matrix ECC200 image in Visual Studio .NET applications.
Standoff insulators Treated 4 4 fence post Coax to XMTR
DataMatrix Printer In VS .NET
Using Barcode creation for ASP.NET Control to generate, create Data Matrix image in ASP.NET applications.
Painting ECC200 In .NET Framework
Using Barcode creator for .NET Control to generate, create Data Matrix image in .NET applications.
Ground level
Creating Data Matrix ECC200 In VB.NET
Using Barcode generation for VS .NET Control to generate, create Data Matrix 2d barcode image in VS .NET applications.
Creating Universal Product Code Version A In None
Using Barcode creator for Software Control to generate, create UPC Code image in Software applications.
Back fill
Create Bar Code In None
Using Barcode creator for Software Control to generate, create barcode image in Software applications.
Data Matrix Encoder In None
Using Barcode maker for Software Control to generate, create Data Matrix ECC200 image in Software applications.
radial
Generating UCC - 12 In None
Using Barcode creation for Software Control to generate, create UCC-128 image in Software applications.
Barcode Encoder In None
Using Barcode encoder for Software Control to generate, create bar code image in Software applications.
> 2 ft Ground rod (8 ft)
ITF Maker In None
Using Barcode creation for Software Control to generate, create 2 of 5 Interleaved image in Software applications.
Encoding EAN 128 In Visual Studio .NET
Using Barcode creation for Reporting Service Control to generate, create EAN 128 image in Reporting Service applications.
Gravel
ECC200 Maker In Objective-C
Using Barcode encoder for iPhone Control to generate, create ECC200 image in iPhone applications.
Barcode Decoder In VB.NET
Using Barcode scanner for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
7-12 Ground-mounted vertical
UPC-A Generation In VB.NET
Using Barcode creation for VS .NET Control to generate, create GTIN - 12 image in .NET framework applications.
Matrix Barcode Maker In VS .NET
Using Barcode creation for ASP.NET Control to generate, create 2D Barcode image in ASP.NET applications.
8-Wavelength verticals 197
Code 39 Full ASCII Printer In Java
Using Barcode encoder for Android Control to generate, create Code 3 of 9 image in Android applications.
DataMatrix Encoder In Java
Using Barcode generator for Java Control to generate, create ECC200 image in Java applications.
antenna; second, a system of quarter-wavelength radials is used Remember that the ground system is absolutely essential A method for installing a vertical antenna above ground is shown in Fig 7-13 In this case, a wooden support (2 4 or 4 4) is installed in a manner similar to Fig 7-12, but with a deeper hole to counter the longer length Alternatively, the wooden support is affixed to the side of a building wall, shed, or other preexisting structure Once the support is arranged, however, the method of attachment of the radiator element is the same for the previous case, so that will not be repeated here Electrical connections to the antenna are also shown in Fig 7-13 Because the antenna is above ground level, an electrical counterpoise ground consisting of a system of radials is absolutely essential; at least two radials per band must be provided A small L bracket is used to support the radials and to provide an SO-239 coaxial connector for the coax This connector is a chassis-mounted type with its center conductor connected to the radiator element The shield of the connector is connected to the bracket, so it is also connected to the radial system In some installations, the antenna support structure will require guy wires to keep the structure stable Do not use the radials as guy wires The type of wire that normally works well for radials is too soft, and too easily stretched, for guy wire service Use regular steel guy line, available where TV antenna supplies are sold, for this antenna Make the lengths nonresonant, and break the guy lines up with egg insulators, if necessary, to achieve the nonresonance
8-Wavelength verticals
Figure 7-14 shows the configuration for the 5 8-wavelength vertical antenna Such an antenna generally gives a lower angle of radiation than the more common quarterwavelength radiator, so presumably it works better for long distance The radiator of this antenna is made from 05-in to 15-in aluminum tubing Again, remember that adjacent sizes fit together snugly to form longer sections The physical length of the 5 8-wavelength radiator is found from Lft = or, in meters, Lmeters = 180 FMHz [76] 585 FMHz [75]
The radials are the usual quarter-wavelength, and are made of no 12 or no 14 copper wire These lengths are found from: Lft = 246 FMHz [77]
198 Vertically polarized HF antennas
Stand-off insulators
Radiator element
Wooden support
Metal bracket
Radials
7-13 Details of feedpoint circuit on vertical
8-Wavelength verticals 199
Radiator element
4 8 Radials
Coax to XMTR 7-14 Using a Q section to match the feedpoint impedance of a vertical antenna
or, in meters, Lmeters = 75 FMHz [78]
The feedpoint impedance of the 5 8-wavelength antenna is about 1600 , not a good match for the ordinary coaxial cables that are routinely available on the amateur market Some form of impedance matching is needed One option is to use a broadbanded RF transformer These transformers will work throughout the HF spectrum, and match a wide variety of impedances to the 50- standard system impedance Another option, especially for a single-band antenna, is to use a coaxial cable impedance transformer, such as shown in Fig 7-14 The transformer consists of two sections of coaxial cable joined together, shown as L1 and L 2 in Fig 7-14 The lengths are found from L1 = 122 ft FMHz [79]
200 Vertically polarized HF antennas or L1 = and L2 = L2 = 30 ft FMHz m [711] [712] 38 m FMHz [710]
9 FMHz
Grounded vertical antennas
The vertical antennas presented thus far in this chapter are called series-fed verticals, because the generator is essentially in series with the radiator element Such an antenna must be insulated from ground The other class of vertical is the shuntfed vertical, which is grounded at one end (Fig 7-15) There are three methods of shunt-feeding a grounded vertical antenna: delta, gamma, and omega All three matching systems have exactly the same function: to form an impedance transformation between the antenna radiation resistance, at the feedpoint, and the coaxial cable characteristic impedance, as well as cancelling any reactance in the system The delta feed system is shown in Fig 7-15A In this case, a taut feed wire is connected between a point on the antenna, which represents a specific impedance on
Copyright © OnBarcode.com . All rights reserved.