_getstarted.txt

zip contains tool for Antenna Modelling with examples

	*) Specify ground parameters

	By default a new model is located in 'Free space'. To model an antenna over ground,
	select the right-most 'Ground Params' button and select between Free-space, Perfect-,
	Finite- or SomNec-ground. For now we will use the finite-ground, also know as 'fast-
	ground'. Change from 'User-specified' to 'Average' (Clay/Forest) ground. Conducti-
	vity is now automatically set to 0.005 Siemens and 'Diel-const' is set to 13.

	To view the corresponding NEC-syntax for all wires and other objects we created,
	use 'Options->View Nec data'.

	*) Run NEC-engine and create far-field pattern.

	To run the NEC-engine and evaluate your model, click the 'Run Nec-engine' button 
	(the one with the calculator picture) or push <F7>. A new pop-up window is displayed 
	asking you for additional settings. To create a full 3D far-field pattern, select
	the second option 'far-field pattern', specify 'Full' and a 5 degree resolution. 
	Then click <Generate>.

	If the DirectX based version of 4nec2 is installed, push <F9> to visualize the new 
	antenna-structure Select 'Pattern' or push the 'R' key to see the 3D far-field 
	pattern.

	You can return back to your model by pushing <F6> or clicking the 'Geometry-edit'
	window. You may alter your model (e.g. set to 'Free-space') and recalculate to see
	the results of your changes.

	For another example of creating a T-antenna on a box, see appendix A at the end of
	this document.

2) Show structure, generate data and view currents and phase distribution.

	In this next example it is explained, how to open a NEC antenna model, view/edit
	(4)nec(2) input-file data the traditional way, generate NEC-output, examine and 
	validate structure geometry and display the current- and phase-distribution along 
	the structure. Furthermore some of the more general menu-bar options as available on
	the different 4nec2 forms/windows are discussed.   

	After starting the 4nec2 program by double clicking on the 4nec2 shortcut or on the
	4nec2.exe program-file, a file selecttion window is displayed. This initial window 
	is used to select the (4)nec(2) antenna model file to open and work with. In this first
	example please locate the file ..\4nec2\example1.nec and click the open button.

	If no NEC-output is generated yet for the selected file, the data loaded into 
	4nec2 will be that for the (4)nec(2) input-file. The wire geometry structure specified
	in this file is displayed on the 'geometry' form. You may use the F2 or F3 key's to
	bring the 'Main (F2)' or the 'Geometry (F3)' form to the foreground. 
	To indicate that the you are currently viewing the input-file data, the background
	for the 'Geometry' form is displayed in a none white color. Note also that in this
	case, most of the fields on the 'Main (F2)' form are empty.

	You may use the arrow key's to rotate, shift or zoom the structure, or the Page-up 
	and Page-down key's to zoom-in or -out. To shift the structure up/down or left/right
	you can also use the Control key together with one of the arrow-key's. Use the 'Home'
	key to reset the geometry form. 

	If you have installed the 4nec2X extended version you could use the F9 key to view
	your nec-model using real-time 3D rendering techniques. Use your mouse-buttons (left,
	right or both) to rotate, shift and zoom the model.

	To view the textual contents for the NEC input-file, first check if the default 
	editor is set to 'Notepad edit'. This is done using the 'Settings' menu-bar option
	on the 'Main (F2)' window.
	If set, push the 'F6' button or use the 'Edit->Input-file' menu-bar option on the 
	'Main' window to start the Edit session. The active *.nec input file is loaded in 
	the editor, and you should see something like this:

CM Example 1 :	Dipole in free space    ' Comment cards
CM 		See GetStarted.txt
CE                                      ' End of comment
'
GW 1 9 0 .2418 0 0 .2418 0 .0001        ' Wire 1, 9 segments, halve wavelength long.
GE 0                                    ' End of geometry
'
EX 0 1 5 0 1 0                          ' Voltage source (1+j0) at wire 1 segment 5.
'
FR 0 1 0 0 300 0                        ' Set design frequency (300 Mc).
'
EN                                      ' End of NEC input

	First we see two CM (ComMent) cards, where some explanation is given about the file.
	After these comment cards always a CE (Comment End) card is required. CM cards are
	the original cards used to add NEC comment. 4nec2 also allows you to add comment
	by using a ' character. Everything after this character is treated as comment and 
	ignored by the NEC engine.
	Next we see a GW (Geometry Wire) card, specifying a single dipole wire with a length
	of 2 times .2418 meter. The X, Y and Z coordinates for end-1 are ( 0, -0.2418, 0 )
	and for end-2  ( 0, 0.2418, 0 ). This wire is given a 'tag' number of "1" and is 
	divided into 9 equally long segments. After the GW card(s) always a GE (Geometry End)
	card is required.
	Then we find an EX (excitation) card of type "0", specifying the most commonly used
	voltage-source type. This voltage source is located on the wire with tag 1 and the
	segment with sequence number 5. (seen from end-1). The excitation voltage is spe-
	cified as a default 1 + j0 volts. (1 V at 0 degrees).  
	The (design) frequency for this antenna is specified with the FR card. In the above
	example we specify this as (a single step for a frequency of) 300 Mhz. 
	The end of the input file is marked with an EN card.

	To modify a (4)nec(2) input-file the 'Edit' window is used, but for now we quit this 
	edit session without saving, by clicking the Notepad 'Close' button.

	To start the NEC engine and generate NEC output-data, be sure one of the 4nec2
	forms is on top (has the focus) and push the F7 key. A new pop-up window called 
	'Generate' is displayed. In this window you will be able to specify  different 
	calculation options. Lets start with the first one, called 'use original file'.
	If not already selected, please select this option and push <Enter> or click the 
	'Generate' button.
	When this is done, a black DOS-box is displayed, indicating that the Nec2d.exe
	engine is running. This engine reads the active *.nec input file data, processes the
	given data and writes the calculation results back to the output file. This output
	file is created in the '..\4nec2\out' folder.

	Before starting the engine, the input-file data is pre-processed by 4nec2 to remove
	comment, calculate variables, convert current-sources or perform auto-segmentation.
	The intermediate file with the *.inp extension is sent to the NEC-engine. 
	If NEC errors are reported you can inspect the output-file data using the F8 key 
	or select 'Edit -> Output-file'. To view the 'raw' input-data send to the NEC 
	engine use 'View->Last NEC input' on the 'Geometry (F3)' form.

	When calculations are done, the DOS-box disappears and 4nec2 opens the output-file, 
	reads and displays the generated data on the 'Main' and 'Geometry' form.
	Note that the 'Geometry' background color changes to white and that most fields
	on the 'Main' form are filled with data.

	Before starting the NEC-engine, optionally a 'geometry validation' test is done. 
	If enabled, any geometry errors/warnings are logged. Calculations however are still
	performed. When calculations are done, 4nec2 performs a 'segment validation' test.
	In this test most of the NEC requirements concerning segment-length  and -diameter
	are checked. If errors are detected a message is displayed and the wires/segments
	with errors/warnings are highlighted. Use 'Validate -> run geometry check / run
	segment check' to manually run the tests and/or get more textual information.

	To get more detailed segment info, select the desired segment with the mouse and
	use the left mouse button. With the 'Wire/Segment' menu-bar option you can get the
	same information. Detailed wire information is also available when viewing the 
	input-file structure. The selected wire is highlighted, with an open and a closed
	circle. The closed circle represents end-1, the open circle end-2.

	To view all Segment, use the 'S'(egment) key or select 'Show->Segments'. To view 
	the open Ends, use the 'E'(nds) key or select 'Show->open Ends'. To show the Current
	distribution along the dipole wire use the 'C'(urrent) key or select 'Show->Current'
	To toggle the Phase relationship on and off, enter the 'P'(hase) key or select 
	'Show->Phase'. If detailed segment info is selected (see above), the numerical
	values for the segment current is displayed. With the 'X' key or the 'Wire/Segm->
	Polar/Cartesian' option you can toggle between polar or cartesian notation.

	Another way to show the current distribution along a wire is to select the 'Show->
	single/multi-color' option. This option may be used to evaluate the currents for
	complex structures.
	

3) Generate Far-field data and view 2D polar and 3D far field patterns.

	In this example the Example2.nec input file is used. If 4nec2 is already active,
	please use 'Ctrl+O' or 'File->Open' on the 'main' and select the Example2.nec file.


CM Example 2 :  Loaded dipole in free space
CM              See GetStarted.txt
CE              End of comment
'
SY len=.4836                            ' Symbol: length=wavelength/4
'
GW 1 9 0 -len/2 0 0 len/2 0 .0001       ' Wire 1, 9 segments, halve wavelength long.
GE 0                                    ' End of geometry
'
LD 5 1 0 0 5.8001E7                     ' Wire conductivity for copper
'
EX 0 1 5 0 1 0                          ' Voltage source (1+j0) at wire 1 segment 5.
FR 0 1 0 0 300 0                        ' Set design frequency (300 Mc).
EN                                      ' End of NEC input


	At first the structure looks the same as Example 1, however if you use the F6 key
	you will notice some differences. First of all, special 4nec2 "SY" cards are inclu-
	ded. With this card it is possible to specify symbols(VARIABLES), constants or 
	mathematical expressions (equations). In this example the dipole length is repre-
	sented by the symbol 'len'. It has the value 0.4836. In the GW card this variable
	is used as 'len/2' to specify the Y coordinates for both ends of the dipole wire.

	Furthermore a LD 5 (wire loading) card was added to specify the wire conductivity
	for the dipole. In the 'Geometry' form you can use the 'W'(ire) key of 'Show->Wire 
	loading' to examine all the loaded segments, they are displayed in a orange/brown 
	color. You may also use 'Show->Excitation/Loading info' on the Main form or click
	on or near a wire in the Geometry form to view additional Wire information.
	
	To generate a 3D far-field pattern, press the F7 key and select the second option
	called 'Far-field pattern'. In the lower half of the form, additional fields are 
	displayed to specify a certain pattern-resolution and a check-box to include the 
	surface wave into the combined far-field pattern. 

	The pattern-resolution specified how fine or course the generated pattern is. Fur-
	thermore this affects 4nec2 memory-usage and NEC processing-time. For 'simple'
	antennas like our dipole a resolution of 5 or 10 degrees will be fine. For multi-
	element antennas like the 'emeyagi.nec' a reolution of 1 degree may be needed. 

	For now, the 'surface wave' option should not be selected. The option boxes
	on the right should be set to 'Default pattern'. Experienced NEC-users can use
	one of the other options or even use the 'more' button to get extra options.

	When the 'Generate' button is pushed, the NEC-engine starts and new output data is
	generated. After the calculations are done a third form called the 'Pattern' form 
	is displayed. In this form the 2D horizontal or vertical polar far-field patterns 
	are made available. If this form is on top, with the arrow-keys you can select the 
	pattern for different theta or phi angles. With the 'G'(eometry) key or the 'Show->
	Structure' the geometry structure is displayed on the pattern form. 

	To view the 3D pattern, select the 'Geometry' form (F3) and push the 'R' key or use
	the 'Show->Near/Far-field' option. You may use the mouse-buttons or the arrow- and 
	page-up/down keys to move, rotate or zoom the 3D pattern. If the 3D pattern on the
	'Geometry' form is enabled and the 'Pattern' form is selected (F4), the color for 
	the 3D pattern changes and the 2D pattern for the selected theta (elevation) or phi
	(azimuth) angle is highlighted. This helps you to understand where the selected 2D
	pattern is located in the full 3D-pattern.

	On the 'Pattern' form you can use the 'L' key to switch between linear and (semi)