Getting started with the 4NEC2 version 5.2 visualization and optimization tool for NEC-2.

Content:

1) Show structure, generate data and view currents and phase distribution.
2) Generate Far-field data and view 2D polar and 3D far field patterns.
3) Generate frequency loop graphical-data.
4) Optimize antenna performance.
5) Evaluate antenna performance.
6) Generate and view Near-field data.
7) Generate and use ItsHF area-coverage propagation data.
[8) Generate and use ItsHF point-to-point propagation data.]

	For this introduction on 4nec2 it is helpfull if the reader has some basic know-
	ledge about modeling 3-dimensional wire structures (with nec-2). Especially for
	the GW, EX, FR and LD cards. Informations about this can be found in the initial 
	pages of the nec-2 user-manual available on the internet at www.qsl.net/wb6tpu/
	swindex.html.
	
1) Show structure, generate data and view currents and phase distribution.

	In this first basic example it is explained, how to open a nec-2 antenna model, 
	generate nec-2 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 are 
	discussed.   

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

	If no nec-2 output is generated yet for the selected file, the data loaded into 
	4nec2 will be that for the 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' or the 'Geometry' 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' form are empty.

	You may use the arrow key's to rotate 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 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-2 input file, use the 'F6' button or the
	'Edit->Input-file' menu-bar option on the 'Main' form. The active *.nec input file
	is loaded in the nec2 based 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. CE cards are
	the original cards used to add nec-2 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-2 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 (one linear step for a frequency of) 300 Mhz.
	The end of the input file is marked with an EN card.

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

	To start the nec-2 engine and generate nec-2 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, 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-2 engine. If nec-2
	errors are reported you may inspect nec-2 input by using "View->Last nec-2 input" 
	on the Geometry 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.

	When reading and displaying output data, 4nec2 performs a 'structure validation'
	test. In this test most of the nec-2 requirements concerning segment-length 
	and -diameter are checked. If errors are detected a message is displayed. With the
	menu-bar option 'Show -> Validate' it is possible to highlight the wires/segments 
	with error conditions. With the 'output to log-file' option, all warnings and error
	are reported as a text file.

	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 displayed in blue color, 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.
	

2) 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, constants or mathematical-
	expressions (equations). In this example the dipole length is represented by the 
	symbol 'len'. It has the value 0.4836. In the GW card this symbol 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-2 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 selection boxes
	on the right should be set to the default, 1: ver/hor/tot gain, 0: no-normaliza-
	tio, 0: power-gain, 0: no averaging. (Please consult the RP card in the nec2 user
	manual for detailed information about using this 'XNDA' field).

	When the 'Generate' button is pushed, the nec2d 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 or phi 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 loga-
	rithmic scaling. You may use the Page-up/down key's in combination with the <Shift>
	or <Ctrl> key to alter the high and low ranges. These functions are also available
	through the 'Far field' menu-bar option. By default the pattern is normalized for
	maximum gain for current the/Phi. The Max-gain value is displayed in the upper left
	corner. To normalize against the overall maximum gain, press the <Home> key. To
	disable all normalization, press the <Home> key again. A third push will bring you
	back to the default state.

	To get the gain and angle for a particular point on the pattern it is possible to 
	select a point on the pattern line with the mouse and click the right mouse button.
	Use the 'I'(nfo) key or 'Show->Info' the get additional information about maximum
	gain, front to back ratio and beam-width. 
	By default the total field is displayed, to view the other generated patterns use
	the ','(<) and '.'(>) key's.	

3) Generate frequency loop graphical-data

	In this third example the Example3.nec input file is loaded. In this file an
	inverted-V antenna for 80 meter is used. The top of this antenna is brought to
	a height of 20 meters, and a ground specification (GN card) is included.
	For easy reading, Tab characters are used to separate the different nec2 card 
	values. If you take a look at the 4nec2 input file (F6), you will see three types 
	of 'GN' cards, two of them are preceded by a " ' " sign, so they are treated as 
	4nec2 comment. The other one (the GN 2) card is 'active', so in this example the 
	high accuracy Sommerfeld-Norton ground is used. A conductivity of 0.006 S/m and a 
	dielectric constant of 14 is used (average ground, see the 4nec2 help)   

CM Example 3 :	Inverted-V over average ground
CM 			See GetStarted.txt
CE 
SY hgh=20				' Height
SY len=20				' Wire length
SY ang=110 				' Angle between sloping wires
SY Z=len*cos(ang/2), X=len*sin(ang/2)	' Get delta-Z and -X distances
'
GW	1	20	-X	0	hgh-Z	-0.1	0	hgh	#12 ' radius for
GW	2	1	-0.1	0	hgh	0.1	0	hgh	#12 ' #12 wire
GW	3	20	0.1	0	hgh	X	0	hgh-z	#12
GE
'
'GN	-1						' Perfect ground
'GN	0	0	0	0	14	.006	' Finite ground
GN	2	0	0	0	14	.006	' Sommerfeld ground
'
EX	0	2	1	0	1	0	' Default voltage source
FR	0	1	0	0	3.680		' Design frequency
'
EN							' End of file

	In this example the 'sin' and 'cos' mathematical functions are used to calculate
	the delta-X and -Z distances for the outer ends of both sloping wires.

	To generate frequency loop (frequency sweep) data, Enter the F7 key, and select
	'use frequency loop'. With this calculation-option graphs are generated for: 
	Forward-gain, Front-to-back- and front-to-rear-ratio, SWR and input impedance.

	When selecting this option additional input-boxes appear. For now we select the
	'Gain' option. Please enter a frequency start-value of 3.5, a stop value of 4 and
	a step-size of .02 Mhz. Enter a value of 90 for the Phi angle and a value of 55 for
	the Theta angle, and click the 'Generate' button.
	When calculations are done a third window is displayed called the 'Impedance' win-
	dow. In this window you can switch between "S"(SWR), "G"(Gain) and "I"(impedance)
	display. Use the "L" key to switch between linear and logarithmic Y axis scaling.
	Use the "F" key to change to X-axis scaling. By default the SWR, R-in and Z-in 
	graphs are set to logarithmic, the others default to linear. For linear scaling,
	you may the 'Up','Down', 'Page-up' and 'Page-Down' keys to move and zoom the graph.
	Use the 'Tab' key to select one or both graphs.
	
	4nec2 also has the possibility to display the input impedances on a Smith chart. 
	Enter the F11 key to select this option. Use the cursor keys to select a specific
	frequency. More experienced users may use the <Shift> key in conjunction with the
	cursor keys to 'add' a certain length of feedline. Use <Home> to (de)normalize.

	To view the changing for, for example, the vertical far-field pattern when fre-
	quency increases from 3 to 30 Mhz, please enter F7, 'use frequency loop' and select
	the 'Ver'tical option. Enter 3, 30 and .5 for frequency start, stop and step-size. 
	Again enter 55 for the Theta- and 90 for the Phi-angle of our direction of interest.
	Click 'Generate' and when calculations are done, you can 'walk' through the dif-
	ferent vertical far-field patterns on the 'Pattern' (F4) form with the 'Left' and 
	'Right' arrow key's.

	Note: Select the Nec2dSX engine for increased accuracy when running a frequency-
		loop using SomNec ground settings.
		
4) Optimize antenna performance.

	In this example again the 'Example3.nec' input file is used, but now we will opti-
	mize antenna-performance. As a first try we will use the traditional hill-climbing
	optimizer and optimize radiator length for resonance. To do this, start the Optimi-
	zer by entering the F12 key. A new window appears with a number of selection- and
	input-boxes. First we set the traditional optimizer by selecting 'Optimize' in the 
	Function-box and 'Default' in the Option-box. After this we select the variable(s)
	we want to optimize, by clicking on the 'len' variable in the list-box with the
	'variables' heading. The selected variable(s) will show-up in the right list-box.
	
	Furthermore you must select one or more antenna parameters to optimize, together 
	with their "importance" (the weighting factor, contributing in the total result)
	To optimize for resonance, please enter a value of 100 in the 'X-a' box, meaning
	the Reactive component is the only thing to optimize. To get resonance, this compo-
	nent must be minimized. This is the default setting. (Click with the right mouse 
	key on one of the parameter to change this default target) Be sure all other para-
	meters are set to zero. 

	After clicking the 'Optimize' button the optimizing process starts and the button 
	text changes to 'Halt'.

	In the upper right box, the selected variables together with the direction and 
	relative amount in which they are changed are displayed. In the lower left box the
	calculated parameter values are displayed for each new optimization step, together
	with the calculated overall result (Figure Of Merit) and the active step-size. 
	In the lower right box the corresponding variable size(s) is/are listed, so it is
	possible to follow the optimizing process.

	After some time the process should stop with the message 'Optimized in XX steps',
	indicating the optimization is ready. To premature abort the process, you may click
	the 'Halt' button. It is possible the process is not immediately halted. If so, 
	please wait till the active calculation step is ready. Sometimes it may be necessary
	to click the button once more. After the process is ready/aborted, you may change 
	the variables or parameters and continue optimization by clicking the 'Resume'
	button.	

	If the optimization results are OK, you may use the 'Save results' button to save 
	the new variable value(s) in the *.nec input-file. Use 'Exit' to quit the optimizer
	without saving.

	In the same way you can optimize for Forward-Gain, Front-to-back- and/or Front-to-
	Rear-ratio. If one or more of these parameters are selected, you must also specify
	the Forward-Gain and (for none default angles) backward-gain angle to calculate for.
	For quick optimizations, a resolution of "0" (zero) could be used. In this case 
	only the Gain for the specified Forward- and backward-angles are calculated and no
	additional Front-to-Rear data is calculated.

	For more precise optimizations, a none-zero resolution (e.g. 5 degrees) could be set.
	Now a complete 3D pattern is calculated for each optimization step, so the difference
	between the Forward lobe and the largest side-lobe in the backward 180 degree part of
	the pattern is calculated and displayed as the Front-to-rear ratio.

	If optimizing for Gain or F/B, one may also specify a delta Theta and/or Phi for the 
	forward- and/or the backward-angle. If a none-zero value is specified, the gain is
	averaged over the range between Phi - delta_phi and Phi + delta_phi. The same holds 
	for the Theta angle. 

	Mostly optimization is performed for total-gain. If required, however you may opti-
	mize for horizontal/vertical-gain or E-theta/E-phi. Optimization with included sur-
	face-wave is also possible. 

	Variable changes are reflected on the Geometry view. To view them, after starting
	the optimization process, please move and/or resize the optimizer window to the 
	lower left part of the screen. If optimization is done for Gain and a none-zero
	resolution is set, the far-field pattern changes are also reflected on the Geometry
	(if 3D pattern is enabled) and the Pattern form. The optimization steps are logged
	in the optimzer.log log-file. This file can be viewed with 'Show -> Optimizer log'
	in the Geometry window.

5) Evaluate antenna performance.

	With version 4.3 and later it is possible to evaluate and graphically visualize the
	effect of antenna variable changes. To make this possible an evaluation function 
	has been added in the Optimizer function box. If, after enabling the optimizer 
	window (F12), this Evaluation function is selected, the optimizer window changes a 
	bit. The 'parameters to optimize' are replaced by 'Delta variable changes in %' and
	a new input box called 'Nr of steps' is displayed. Furthermore you are able to 
	select between the vertical of horizontal or 3D far-field pattern.

	To evaluate the effect of changing antenna height from 20 to 30 meters, we use the
	'3el-inverted-V.nec' file. After loading this input file, start the optimizer/eva-
	luator, select 'Evaluate' and select 'hgh' as the variable to evaluate. This varia-
	ble it now added to the list of 'Variable changes in %' and a default number of 10
	is displayed. To evaluate a height change from 20 to 30 meters, 10 (abs)steps of 10
	% are required, so fill in an amount of 10 for the 'nr of steps'. (Be sure the 
	Settings -> Optimizer-> Absolute steps option in the Main form is checked.) 

	Set the Theta- and Phi-values to 55 and 90 degrees to specify the angle for which
	Gain is calculated. Specify a resolution of 10 degrees. (If resolution equals zero,
	this will greatly increase evaluation speed, however no pattern is calculated and
	displayed)

	Click the Start button to start the evaluation process. First of all an initial 
	step is made with the default height of 20 meters. After that 10 incremental steps
	are made in which each step the height is incremented by 10% from 20 meters is 2 
	meters.

	The resulting SWR, Gain, F/B, F/R, R-in, X-in and efficiency values for each step 
	are reported in the 'calculated results' box. The resulting horizontal far-field 
	pattern for each step is updated on the Pattern and Geometry window.

	If all steps are done, you may use the 'Exit' button to close the optimizer/evalua-
	tor window or change/add/remove variables, change settings and/or proceed with 
	another range of steps, by clicking the 'Restart' button.
	
	After closing the window, all results for the last sweep are reported in the graphs
	on the 'F5' form. The horizontal or vertical patterns (according your selection)
	for the different evaluation steps are available on the Geometry form. Use the
	Right- and Left-arrow-key's to switch between steps. Use 'Show -> Optimizer log' on
	the Geometry window to view or print the last evaluation results.

	Note however that as distinct from the default 4nec2 operation, the evaluation
	results are only stored in memory, and not in a nec2 output file. So, if 4nec2 is
	left or the input file is viewed or another 4nec2 file is selected. The evaluation
	results are lost. The evaluation log-file is kept as long as a new optimization or
	evaluation is done. 

6) Generate and view Near-field data

	As an example to generate near-field data, the file NearFld.nec is included in
	the package. To use this example, please load this file and push the F7 key to
	get the 'Generate' window. Select 'Use original file', to start the calculation.
	This input-file already contains the required NE card is, so it is not yet 
	necessary to specify any near-field parameters. Calculations will take some time,
	because almost 30.000 near-field points are calculated. 

	When calculations are done, the Pattern windows is displayed with the 'Near-field'
	lay-out. Mostly initially you will see a blue plane with on the left a color-bar
	telling on the left, telling you what field-strength is represented by a certain 
	color. The maximum lever will be in the range > 10000 volts/m. This is due to the
	fact that one or more of the calculation points will be very close (or maybe on) a
	geometry wire with high RF-voltage/current.

	To get rid of these unusable high values, please use 'Near-field -> Ignore high 
	values" or push the <Del> key. You are asked for maximum field-strength. Please
	enter a value of 250 (V/m). The display should now change to a more colorful
	view. The color-bar on the left is also updated.
	Another way to change the color-resolution, is to use the <Shift> together with the
	<Page-up> or <Page-down> key. This will change the linear scale to a more logarith-
	mic scale. Use 'Show -> Geometry' or the "G" key to display the geometry- structure.
	
	Initially the field-strength on the XY plane for a certain Z value is displayed.
	To change the Z-value use the cursor-left or -right key's. To change between
	XY, YZ and XZ plane, use the spacebar.
	On the Geometry form you are also able to display the Near-field points. Use
	'Show -> Near/far field" or push the "R" key. Use the spacebar to switch between
	3D view, or 2D XY, YZ or XZ view. Use <Shift> plus the arrow-keys to change the
	2D plane coordinates. Use <Page-up>/<Page-down> to change the dot-size.

	On the 'Pattern' form on the left and on the right of the 2D plane, two black
	lines are displayed. These lines are used to select a certain Y- or Z value for
	displaying the field-strength as a graph. Use the Up/Down arrow keys to change
	position, use <Page-Up>/<Page-down> to switch between 2D and graph viewing.

7) Generate and use ItsHF area-coverage propagation data.

	This feature works in conjunction with the NTIA/ITS HF propagation software ICEPAC,
	VOACAP & REC533. This software is freely available on the internet.

	After installing this software, you should create a '\nec' sub-folder in the
	'\antenna', '\areadata' and the '\saved' folder under the ItsHF main-folder.
	These folders are used by 4nec2 to place the generated (data) files. Under 
	'Settings->Folders' please specify your ItsHF main-folder and the 'nec' sub-
	folder names, for instance 'C\ITSHFBC\ and 'NEC\'. 
	
	Furthermore, be sure all 3 options under 'Settings->ItsHF settings->Area Coverage' 
	are checked.

	With this first try, we use the 3el-inverted-V.nec as our input file. First we run a
	standard 3D far field calculation, to determine the Phi angle for the main lobe. For
	this antenna this is 90 degrees (positive theta).

	After pushing the <F7> key again, we now select the 'ItsHF area coverage' option. If
	not already set, specify 90 degrees for the main beam angle and 7.05 Mhz for the 
	design frequency and push <Generate>. After running the nec2d(x) engine the ItsHF 
	engine is started (characterized by the counting number sequence), and when done, a
	color-full map is displayed, indicating the signal power distribution for the selec-
	ted antenna over Europe.

	The plot settings for this map are set in the '3el-inve.ice' file (truncated to eight
	char's) located in the '\antenna\nec' folder. You may start the ItsHF ICEAREA pro-
	gram to open, view or modify this file. Use 'run->calculate->Save/Calculate/Screen'
	to create a new plot after you modified one or more settings. Just rerun the 4nec2
	'Area-coverage' function to restore the original file.

	In the '3el-inve.ice' file you will see that for the TX-antenna, '3el-inve.n13' is 
	set, indicating our nec-2 input antenna. This type-13 antenna-file is located in the 
	'\antenna\nec' sub-folder. You may use the HFant program to open this file and 
	view the pattern.

	Each time a 'Area-Coverage' calculation is done by 4nec2, a new *.ice input file is
	created. This file is based on the information included in a default ItsHF input-
	file called 4NEC2.ICE placed in the \antenna\default folder. Modify this file to
	specify your personnel settings, like transmitter/receiver location, power etc or to
	specify different time or date. 
	The next time you run a 'area-coverage' calculation this data is imported in the
	<antenna>.ice input file and reflected in the area-coverage plot.

	Evaluate area-coverage:

	With the 'Evaluator' function it is possible to let 4nec2 automatically generate a 
	specified range of area-plots for you. For instance, representing the area-coverage
	change when increasing the antenna height from 15 to 30 meters.

	To do this, again select the 3el-inverted-V.nec file as our antenna of interest. 
	Before starting the evaluation, please change the 'hgh' (height) variable from the 
	original 21 to 15 meters.

	When done, push <F12> to start the optimizer/evaluator. Select 'Area-coverage' in
	the upper left function box, and select 'hgh' as the variable to evaluate. Set 90
	degrees as the Phi angle for the main-beam and specify 10 steps of 10% variable 
	change, and push <Start>.

	During all the calculations, which will take some time, you will see the windows
	popping on and off the screen. After some time this stops and the Evaluator title-
	bar will show 'Evaluation ready'. You may now exit the evaluator and 4nec2.

	To view all the generated plots, we will use the 'Viewer' program, included in the
	4nec2 package. After starting 'View.exe' in the 4nec2\exe folder, select 'File->
	Open new picture' and select the '..\areadata\nec' folder in you ItsHF main-folder.
	Specify '*.ig1' as the file extension and select the '3el-inv00.ig1' file as
	the file to open. (the last two zeros specify the first picture for the generated 
	plot sequence)
	Next you are asked for the number of pictures to load, If the previous evaluation run
	was completely finished, a number of 11 should be set. Select <OK> to load all eleven
	pictures.

	Again a number of (plot) windows will pop on and off the screen, automatically
	cutting and pasting the plot maps into the viewer program. After some time the 
	message '11 pictures pasted' should show up, indicating all area-plots are loaded. 

	Latest test-results on different systems show that this automatic cutting and 
	pasting appears to be sensitive. If you should experience difficulties during this
	process, please contact me so I can deliver you an alternative.

	After confirming the message you can toggle between all loaded area-plots by using
	the up- and down-arrow keys. You are now able to evaluate the effect of changing
	antenna height on area-coverage. You will notice that for a height of around 21 
	meters the optimum F/B ratio is reached. This was the original height the antenna was
	optimized for.
	
	When leaving the 'Viewer' you are asked if you would want to save the loaded files
	as bitmap *.bmp files. This allows for faster loading the next time you want to view
	the generated area-plots. Choose Yes to convert all *.ig1 to *.bmp files. Choose No
	if you have limited disk space.


	To be continued.....

	(it is suggested to periodically check the 'unofficial Nec-2 page' for new versions)


p.s.	I apologize for my poor English which is far from perfect, but nevertheless I hope 
	this document, including all the syntax-errors, does deliver some usefull information.
