.net barcode reader free Grounding in Software

Creating DataMatrix in Software Grounding

Grounding
Recognizing Data Matrix In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Draw Data Matrix ECC200 In None
Using Barcode generator for Software Control to generate, create DataMatrix image in Software applications.
Still another problem involves grounding The ground system of a higher-frequency vertical antenna can be installed using /4 radials buried a few inches below the surface But that same idea becomes problematic when the radials are 66 or 125 ft long Burying half a dozen 125-ft radials might remind your neighbors of the Galloping Gung-Ho Gopher and not to their amusement! There are, however, some solutions to the problem without having you buy a farm in the flatter regions of the midwest For example, the length problem can be solved by using one of the bent dipoles covered in Chap 10 No, they are not
Decode Data Matrix ECC200 In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
Printing ECC200 In Visual C#
Using Barcode creation for .NET Control to generate, create ECC200 image in VS .NET applications.
Copyright 2001 - the McGraw-Hill Companies
Data Matrix 2d Barcode Maker In .NET
Using Barcode creator for ASP.NET Control to generate, create DataMatrix image in ASP.NET applications.
Data Matrix ECC200 Drawer In .NET
Using Barcode drawer for Visual Studio .NET Control to generate, create Data Matrix 2d barcode image in VS .NET applications.
502 Antennas for low-frequency operation as effective as an antenna that is correctly installed But they will serve to get you on the air Some of them work surprisingly well The ground radial problem can be solved by bending the radial system around your property (Fig 26-1) You will never have to cross your neighbor s line And, as for the gopher track appearance, it is not necessary to work sloppily, and you can install radials so that nary an eye, practiced or otherwise, can see their location
ECC200 Maker In VB.NET
Using Barcode printer for .NET framework Control to generate, create ECC200 image in .NET applications.
Bar Code Drawer In None
Using Barcode generator for Software Control to generate, create barcode image in Software applications.
Shortened vertical antennas
Code 128 Code Set C Encoder In None
Using Barcode drawer for Software Control to generate, create Code-128 image in Software applications.
Paint UPC-A Supplement 5 In None
Using Barcode generation for Software Control to generate, create GS1 - 12 image in Software applications.
The biggest problem for most low-frequency DXers, as you have seen, is the excessive size of antennas for those frequencies; it is not for nothing that those AM broadcast band (<16 MHz) towers are usually hundreds of feet tall But there are ways to shorten an antenna not for free, because the TANSTAAFL* principle still
European Article Number 13 Generation In None
Using Barcode encoder for Software Control to generate, create EAN-13 image in Software applications.
Make DataMatrix In None
Using Barcode generator for Software Control to generate, create DataMatrix image in Software applications.
Property lines Possible radial patterns
UPCE Printer In None
Using Barcode printer for Software Control to generate, create UCC - 12 image in Software applications.
Draw Data Matrix In Java
Using Barcode maker for Eclipse BIRT Control to generate, create Data Matrix ECC200 image in BIRT reports applications.
Fence House
Generate ANSI/AIM Code 128 In Java
Using Barcode printer for Java Control to generate, create USS Code 128 image in Java applications.
Reading Data Matrix ECC200 In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
Fence
Code 128 Code Set B Maker In .NET Framework
Using Barcode drawer for ASP.NET Control to generate, create Code 128 Code Set A image in ASP.NET applications.
Code 39 Encoder In C#
Using Barcode generation for .NET framework Control to generate, create Code-39 image in .NET applications.
26-1 Methods for laying out low-frequency radials in a cramped space
GS1 128 Generation In Java
Using Barcode maker for Java Control to generate, create EAN128 image in Java applications.
Draw Barcode In Objective-C
Using Barcode drawer for iPhone Control to generate, create bar code image in iPhone applications.
* TANSTAAFL
= There ain t no such thing as a free lunch!
Shortened vertical antennas 503 applies to a point where it becomes mechanically possible Let me reiterate once again that these compensation antennas will not work as well as a properly installed full-sized antenna, but they will serve to get you on the air on frequencies where it is otherwise utterly impossible Several different compensation configurations are popular, and these are shown in Fig 26-2
To XMTR
To XMTR
To XMTR
To XMTR
To XMTR
26-2 Inductance loading of vertical antennas: (A) center; (B) top; (C) base; (D) linear or length-loaded; (E) linear hairpin-loaded
504 Antennas for low-frequency operation The basic foundation for these antennas is a very short vertical antenna The standard vertical antenna is a quarter-wavelength ( /4) (ie, 90 electrical length), and it is unbalanced with respect to ground Recall that a vertical antenna that is too short for its operating frequency (ie, less than /4) will exhibit capacitive reactance In order to resonate that antenna, it is necessary to cancel the capacitive reactance with an equivalent inductive reactance, such as XL = XC By placing an inductance in series with the antenna radiator element, therefore, we can effectively lengthen it electrically Of course, what is really happening is that the effects of the lower operating frequency are being accommodated (ie, cancelled out ) of a too-short antenna An antenna that is reactance-compensated for a different frequency is said to be loaded, or in the case of a very low frequency antenna, inductively loaded Three basic forms of loading are popular: discrete loading, continuous loading, and linear loading Discrete loading means that there is a discrete, or lumped, inductance in series with the antenna radiator (Figs 26-2A through 26-2C) These antennas are so constructed that a loading coil is placed at the center (Fig 26-2A), top (Fig 26-2B), or bottom (Fig 26-2C) of the radiator element You will recognize these configurations as being the same as those found on mobile antennas Indeed, low-band mobile antennas can be used in both mobile and fixed installations Note, however, that although it is convenient to use mobile antennas for fixed locations (because they are easily available in store bought form); they are less efficient than other versions of the same concept The reason is that the mobile antenna, for low frequencies, tends to be based on the standard 96- to 102-in whip antenna used by amateur operators on 10 m or Citizens Band operators on 11 m In fixed locations, on the other hand, longer radiator elements (which are more efficient) are more easily handled For example, a 16- to 30-ft high aluminum radiator element can easily be constructed of readily available materials The 16-ft element can be bought in the form of one or two lengths of 1- to 15-in aluminum tubing at do-it-yourself outlets A problem seen with these antennas is that they tend to be rather high Q, so the bandwidth is necessarily narrow An antenna might work in the center of a band, but present a high VSWR at the ends of the band, and thus be unusable This problem is solved by making the inductor variable so that slightly different inductance values can be selected at different frequencies across the band For the base-loaded version (Fig 26-2C), this is particularly easy: a rotary inductor (perhaps motor driven for remote operation) can be used For the other configurations, a tapped fixed inductor can be used instead Each tap represents a different inductance value Either clip connectors, or relay connections, can be used to select which tap is used A continuously loaded antenna has the inductance distributed along the entire length of the radiator (Fig 26-2D) Typical of these antennas is the helically wound verticals in which about a half-wavelength of insulated wire is wound over an insulating form (such as a length of PVC pipe or a wooden dowel); the turns of the coil are spread out over the entire length of the insulated support Linear loading (Fig 26-2E) is an arrangement whereby a section of the antenna is folded back on itself like a stub Antennas of this sort have been successfully
Shortened horizontal antennas 505 built from the same type of aluminum tubing as regular verticals For 75/80-m (375-MHz) operation a length of 30 ft for the radiator represents 41 , while a normal /4 vertical is 90 The difference between 90 and 41 of electrical length is made up by the hairpin structure at the base
Copyright © OnBarcode.com . All rights reserved.