.net barcode reader library General antenna mechanical construction techniques in Software

Maker ECC200 in Software General antenna mechanical construction techniques

550 General antenna mechanical construction techniques
Data Matrix 2d Barcode Decoder In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Data Matrix 2d Barcode Creator In None
Using Barcode drawer for Software Control to generate, create ECC200 image in Software applications.
28-4B Balun/center insulator
Decoding DataMatrix In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
Printing ECC200 In C#.NET
Using Barcode creation for .NET Control to generate, create Data Matrix 2d barcode image in VS .NET applications.
Figure 28-6 shows the dipole installed The ends of the two wire elements are connected to end insulators, which are in turn supported by rope to a vertical support (eg, mast, tree, roof line of the house, etc) Although shown nice and straight here, the actual installation will droop a bit in the center due to the weights of the center insulator or balun, the coaxial cable, and the wire itself Gravity! Note that the coaxial cable is formed into a 15- to 25-cm loop just below the coaxial connector to the center insulator or balun This forms a species of RF choke to keep currents from flowing in the outer shield and improves the pattern The coaxial cable loop is bound together with black electrician s tape or some similar adhesive medium and then fastened to the top eyelet with stout string or fishing line for strain relief
Painting DataMatrix In .NET Framework
Using Barcode generator for ASP.NET Control to generate, create Data Matrix ECC200 image in ASP.NET applications.
Draw DataMatrix In Visual Studio .NET
Using Barcode generator for .NET framework Control to generate, create Data Matrix image in VS .NET applications.
Wire antenna construction 551
Generating DataMatrix In VB.NET
Using Barcode generation for .NET framework Control to generate, create Data Matrix ECC200 image in Visual Studio .NET applications.
Draw Data Matrix 2d Barcode In None
Using Barcode maker for Software Control to generate, create Data Matrix ECC200 image in Software applications.
28-5 Center insulator/balun connections
EAN 13 Generation In None
Using Barcode maker for Software Control to generate, create EAN / UCC - 13 image in Software applications.
Barcode Drawer In None
Using Barcode printer for Software Control to generate, create barcode image in Software applications.
Support rope
Encode GS1-128 In None
Using Barcode encoder for Software Control to generate, create UCC.EAN - 128 image in Software applications.
Barcode Generator In None
Using Barcode encoder for Software Control to generate, create barcode image in Software applications.
The support rope selected should be large enough to provide support but small enough to fit through the holes of the end insulators Cotton rope is singularly unsuited to this task because it weathers poorly and will rot through in short order Nylon rope, sail rope, and parachute rope are perhaps the best types, especially if a particular lot has been tested for high tensile strength Remember, the wind loading of your antenna, even a short dipole, can be tremendous!
Print Leitcode In None
Using Barcode encoder for Software Control to generate, create Leitcode image in Software applications.
UPC-A Supplement 2 Scanner In C#
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
End insulators
Linear Creator In C#.NET
Using Barcode maker for Visual Studio .NET Control to generate, create Linear 1D Barcode image in .NET framework applications.
Recognize UPC Code In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
End insulators come in a large variety of shapes and sizes (I have even seen one chap use old toothbrushes, suitably drilled, of course) The main categories, however, are represented in Fig 28-7 The version in Fig 28-7A is the standard form, whereas that in Fig 28-7B is an egg insulator The egg insulator has two sets of wire grooves and through-holes that are orthogonal to each other (only one set is shown) Wire passes through one hold and set of grooves, and the supporting rope passes through the other hole/groove set The standard form shown in Fig 28-7A has a number of grooves or ridges cut along the body These grooves are intended to lengthen the electrical path between
Barcode Reader In Java
Using Barcode Control SDK for Eclipse BIRT Control to generate, create, read, scan barcode image in BIRT applications.
ECC200 Maker In Visual Basic .NET
Using Barcode printer for VS .NET Control to generate, create ECC200 image in Visual Studio .NET applications.
552 General antenna mechanical construction techniques
Recognize Bar Code In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
Barcode Scanner In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
28-6 Dipole and wire antenna installation
Wire antenna construction 553 ends of the insulator and therefore serve to reduce losses in the insulator Typical materials used to construct insulators include ceramic, glass, nylon, and plastics Figure 28-8 shows the connections to the end insulator The electrical connections to the antenna wire are the same as for the center insulator The only proviso here is that for transmitting antennas, it is wise not to leave any sharp points sticking up The end of the dipole is at high RF voltages, so sharp points tend to cause corona sparking Cut off any extraneous leads that form sharp points, and then smooth the whole affair down with tinning (ie, solder) The rope is treated in a similar manner as the wire, but it must be knotted in some manner that tends to pull together as the rope is pulled into tension Some people use the hangman s knot, but this seems a bit excessive
Strain relief of the antenna
Figure 28-9 shows a method of strain relief for the center insulator or balun This point is at the highest tension and probably is the weakest because of the number of
B 28-7 End insulators
28-8 Connections to end insulators
554 General antenna mechanical construction techniques
28-9 Strain relieving the center insulator or balun
connections and things that can break A suspension rope is run between the antenna s vertical supports, parallel to the antenna wire It is tied to the top eyelet on the center insulator or balun by a short bit of rope about 15 to 20 cm long
Special case of the folded dipole
The folded dipole (Fig 28-10) is a special case of the half-wavelength horizontal dipole It consists of two close-spaced conductors shorted together on the extreme ends One of the conductors is split in the center and used as the feedpoint The feedpoint impedance at resonance is around 280 , so it makes a good match to 300television antenna twin lead The usual practice is to build the entire antenna and feedline out of twin lead An alternative (as shown in Fig 28-10) is to provide a 4:1 balun transformer at the feedpoint to match 75- coaxial cable Despite the fact that 300- TV twin lead is disappearing from the market, the folded dipole maintains a certain following among SWLs and hams The problem is how to install the antenna such that the terribly weak 300- twin lead wires do not break at the slightest provocation Figure 28-11 shows a solution used by one fellow (admittedly a fine worker in plastics and other materials) He fashioned a center insulator and the end insulators from a piece of strong Lucite material The 300- TV twin lead is prepared as shown in Fig 28-11A The antenna element is notched in the center (break along the bottom) for about 1 to 15 cm A hand punch is used to place two or three holes in the center insulation on either side of the break Either a large-size leather punch or a paper punch can be used to make
Copyright © OnBarcode.com . All rights reserved.