
	                    GUY 1.0 Guy-Wire Modeler


	        The GUY.EXE utility makes it easy to investigate the
	effect of guy wires on antenna systems with the AO Antenna
	Optimizer or NEC/Wires.

	        GUY lets you specify guy-wire geometry in simple terms
	like attachment height, anchor distance, insulated-section
	length, etc.  It then generates a file containing AO wire lines
	for all guy-wire sections.  You can maintain guy-wire files for
	several tower installations.  GUY can combine a guy-wire file
	with an AO antenna file to form a complete system model.  You
	can compare results for the composite model with those for the
	antenna alone to study guy-wire/antenna interaction.

	        GUY does not handle AO antenna files that use symbolic
	expressions or shifts and rotates.


	Preliminaries

	        GUY works with filenames supplied on the command line.
	If one filename is given, GUY creates a guy-wire file with the
	specified name plus the extension GUY.  If three filenames are
	given, GUY combines the first file (a guy-wire file) with the
	second (an antenna file) to generate the third (a composite
	antenna file).  Extensions GUY and ANT are not required.  GUY
	always asks permission before overwriting an existing file.

	        GUY normally uses U.S. units.  To use metric units, add
	/m to the command line.  If you always use metric units, you can
	save keystrokes by running GUY from the following batch file:

	                        GUY %1 %2 %3 /m

	        You can abort from GUY at any time by pressing Esc.  An
	output file is neither created nor overwritten when you abort.

	        If you forget how to use GUY, type GUY without
	parameters to display a quick reference.


	Generating Guy-Wire Files

	        GUY asks for a description of the guy-wire file.  The
	description helps identify the file later when you combine it
	with an antenna file.  Press Enter for a default description.

	        Dimensions refer to the centerline of the tower.  You
	can refer dimensions to the tower faces without serious error.

	        GUY generates straight, collinear, unconnected wires to
	represent insulated guy-wire sections.  GUY assumes compression
	insulators are used which effectively overlap wire ends by one
	inch.  GUY lengthens each end an additional half inch to account
	for the capacitive-loading effect of the wire loops.


	        GUY models guy-wire sections with a physically
	coincident overlap of two inches even though the wires are
	electrically insulated.  This takes advantage of the MININEC
	convention that wires are considered to be connected only when
	they have common endpoints.  The overlap does not affect model
	accuracy; it's just a handy way to account for the physical
	properties of compression insulators.

	        GUY assumes that each guy level has three guy wires
	spaced 120 degrees in azimuth.  Each guy wire can have up to 50
	insulated sections.  The final guy sections are generated with
	their lower ends at ground level.  Long grounded sections may
	develop considerable current when the guys are used to support a
	vertical radiator.

	        GUY models the first guy-wire sections attached to the
	tower.  The wires are electrically connected at the tower
	centerline but the tower itself is not modeled.  Thus, tower
	resonances involving the first guy-wire sections are not
	modeled.  Torque bars and tower cross-section are not modeled
	either, so the effective guy-wire diameter in this region is
	much larger than that modeled.  Since the first guy-wire
	sections often are close to an antenna, they may critically
	affect it.  You should keep these modeling limitations in mind
	when the first guy-wire sections are more than a few feet long.

	        GUY does not model guy-wire conductivity or sag.  These
	effects are electrically negligible.


	Combining Files

	        GUY can combine any guy-wire file with any antenna file.
	When the antenna file is in free space, the composite output
	file is in free space.  However, free space symmetric models are
	never generated.  In general, guy wires destroy model symmetry.

	        GUY asks for a description of the composite output file.
	The description becomes the output file title.  Press Enter for
	a default description.

	        Guy-wire files have one set of guys in the +Y direction.
	These wires run somewhat parallel to elements of Yagis and
	cubical quads when the antenna is aimed in the +X direction.
	This orientation usually maximizes coupling between the guy
	wires and the antenna.  You may rotate the guy wires with
	respect to the antenna to simulate antenna rotation.  This will
	reveal additional coupling modes.

	        Unless you rotate the guy wires exactly 30 degrees, the
	composite model will not be symmetrical in azimuth.  In general,
	you must disable X-axis pattern symmetry in AO to generate
	correct patterns.  Even when rotated 30 degrees, free-space
	elevation patterns will not be correct unless symmetry is
	disabled.

	        GUY lets you adjust antenna height in the composite
	output file.  This can greatly alter coupling to the guy wires.

	GUY detects the presence of two planar antennas and prompts for
	the height of each.  For nonplanar antennas like cubical quads,
	antenna height is defined as the average of the highest and
	lowest wire ends.  This number is boom height for quads, but
	this is not true for antennas like delta loops.  In any case,
	pressing Enter to accept the default height leaves all
	z-coordinate values unchanged.

	        It's impractical to model all guy-wire sections for most
	towers because too many pulses are required.  It's also
	unnecessary since remote sections usually have very little
	effect.  GUY includes in the composite output file only guy-wire
	sections closer to the antenna than a specified distance.
	Distance is measured between each end of every antenna wire and
	each end of every guy-wire section.

	        You may specify the number of modeling segments per
	half-wavelength of guy wire.  It's not necessary to use the
	segmentation density normally used for antenna conductors.
	Since guy-wire sections are not likely to be near resonance, you
	can get away with fewer segments.

	        The composite output file uses symbolic dimensions for
	antenna height and for guy-wire segmentation.  This lets you
	easily experiment with these values from within AO.  Guy wires
	use a negative number of segments so that you can employ
	automatic segmentation for the antenna conductors without
	affecting guy-wire segmentation.

