X-Git-Url: https://git.gag.com/?p=debian%2Fsplat;a=blobdiff_plain;f=docs%2Fman%2Fsplat.1;fp=docs%2Fman%2Fsplat.1;h=0000000000000000000000000000000000000000;hp=546907fcdc851cc5f721ca9f3b40fb4b5316b2d7;hb=49350c09f112a613dc33e9a5e116a1a3c0f06997;hpb=2b83ee9944726f29b3f6679fba24a902bcd33c56 diff --git a/docs/man/splat.1 b/docs/man/splat.1 deleted file mode 100644 index 546907f..0000000 --- a/docs/man/splat.1 +++ /dev/null @@ -1,1063 +0,0 @@ -SPLAT!(1) KD2BD Software SPLAT!(1) - - - -NNAAMMEE - splat - An RF SSignal PPropagation, LLoss, AAnd TTerrain analy- - sis tool - -SSYYNNOOPPSSIISS - splat [-t _t_r_a_n_s_m_i_t_t_e_r___s_i_t_e_._q_t_h] [-r _r_e_c_e_i_v_e_r___s_i_t_e_._q_t_h] - [-c _r_x _a_n_t_e_n_n_a _h_e_i_g_h_t _f_o_r _L_O_S _c_o_v_e_r_a_g_e _a_n_a_l_y_s_i_s - _(_f_e_e_t_/_m_e_t_e_r_s_) _(_f_l_o_a_t_)] [-L _r_x _a_n_t_e_n_n_a _h_e_i_g_h_t _f_o_r _L_o_n_g_l_e_y_- - _R_i_c_e _c_o_v_e_r_a_g_e _a_n_a_l_y_s_i_s _(_f_e_e_t_/_m_e_t_e_r_s_) _(_f_l_o_a_t_)] [-p _t_e_r_- - _r_a_i_n___p_r_o_f_i_l_e_._e_x_t] [-e _e_l_e_v_a_t_i_o_n___p_r_o_f_i_l_e_._e_x_t] [-h - _h_e_i_g_h_t___p_r_o_f_i_l_e_._e_x_t] [-H _n_o_r_m_a_l_i_z_e_d___h_e_i_g_h_t___p_r_o_f_i_l_e_._e_x_t] [-l - _L_o_n_g_l_e_y_-_R_i_c_e___p_r_o_f_i_l_e_._e_x_t] [-o _t_o_p_o_g_r_a_p_h_i_c___m_a_p___f_i_l_e_- - _n_a_m_e_._p_p_m] [-b _c_a_r_t_o_g_r_a_p_h_i_c___b_o_u_n_d_a_r_y___f_i_l_e_n_a_m_e_._d_a_t] [-s - _s_i_t_e_/_c_i_t_y___d_a_t_a_b_a_s_e_._d_a_t] [-d _s_d_f___d_i_r_e_c_t_o_r_y___p_a_t_h] [-m _e_a_r_t_h - _r_a_d_i_u_s _m_u_l_t_i_p_l_i_e_r _(_f_l_o_a_t_)] [-f _f_r_e_q_u_e_n_c_y _(_M_H_z_) _f_o_r _F_r_e_s_n_e_l - _z_o_n_e _c_a_l_c_u_l_a_t_i_o_n_s _(_f_l_o_a_t_)] [-R _m_a_x_i_m_u_m _c_o_v_e_r_a_g_e _r_a_d_i_u_s - _(_m_i_l_e_s_/_k_i_l_o_m_e_t_e_r_s_) _(_f_l_o_a_t_)] [-dB _m_a_x_i_m_u_m _a_t_t_e_n_u_a_t_i_o_n _c_o_n_- - _t_o_u_r _t_o _d_i_s_p_l_a_y _o_n _p_a_t_h _l_o_s_s _m_a_p_s _(_8_0_-_2_3_0 _d_B_)] [-nf _d_o _n_o_t - _p_l_o_t _F_r_e_s_n_e_l _z_o_n_e_s _i_n _h_e_i_g_h_t _p_l_o_t_s] [-plo _p_a_t_h___l_o_s_s___o_u_t_- - _p_u_t___f_i_l_e_._t_x_t] [-pli _p_a_t_h___l_o_s_s___i_n_p_u_t___f_i_l_e_._t_x_t] [-udt - _u_s_e_r___d_e_f_i_n_e_d___t_e_r_r_a_i_n___f_i_l_e_._d_a_t] [-n] [-N] [-geo] [-kml] - [-metric] - -DDEESSCCRRIIPPTTIIOONN - SSPPLLAATT!! is a powerful terrestrial RF propagation and ter- - rain analysis tool covering the spectrum between 20 MHz - and 20 GHz. SSPPLLAATT!! is free software, and is designed for - operation on Unix and Linux-based workstations. Redistri- - bution and/or modification is permitted under the terms of - the GNU General Public License as published by the Free - Software Foundation, either version 2 of the License or - any later version. Adoption of SSPPLLAATT!! source code in pro- - prietary or closed-source applications is a violation of - this license, and is ssttrriiccttllyy forbidden. - - SSPPLLAATT!! is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY, without even the implied war- - ranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR- - POSE. See the GNU General Public License for more details. - -IINNTTRROODDUUCCTTIIOONN - Applications of SSPPLLAATT!! include the visualization, design, - and link budget analysis of wireless Wide Area Networks - (WANs), commercial and amateur radio communication systems - above 20 MHz, microwave links, frequency coordination and - interference studies, and the determination of analog and - digital terrestrial radio and television contour regions. - - SSPPLLAATT!! provides RF site engineering data such as great - circle distances and bearings between sites, antenna ele- - vation angles (uptilt), depression angles (downtilt), - antenna height above mean sea level, antenna height above - average terrain, bearings and distances to known obstruc- - tions, and Longley-Rice path attenuation. In addition, - the minimum antenna height requirements needed to clear - terrain, the first Fresnel zone, and 60% of the first - Fresnel zone are also provided. - - SSPPLLAATT!! produces reports, graphs, and high resolution topo- - graphic maps that depict line-of-sight paths, and regional - path loss contours through which expected coverage areas - of transmitters and repeater systems can be obtained. - When performing line-of-sight analysis in situations where - multiple transmitter or repeater sites are employed, - SSPPLLAATT!! determines individual and mutual areas of coverage - within the network specified. - - Simply typing splat on the command line will return a sum- - mary of SSPPLLAATT!!'s command line options: - - --==[ SPLAT! v1.2.0 Available Options... - ]==-- - - -t txsite(s).qth (max of 4) - -r rxsite.qth - -c plot coverage of TX(s) with an RX antenna at X - feet/meters AGL - -L plot path loss map of TX based on an RX at X - feet/meters AGL - -s filename(s) of city/site file(s) to import (max - of 5) - -b filename(s) of cartographic boundary file(s) to - import (5 max) - -p filename of terrain profile graph to plot - -e filename of terrain elevation graph to plot - -h filename of terrain height graph to plot - -H filename of normalized terrain height graph to - plot - -l filename of Longley-Rice graph to plot - -o filename of topographic map to generate (.ppm) - -u filename of user-defined terrain file to import - -d sdf file directory path (overrides path in - ~/.splat_path file) - -n no analysis, brief report - -N no analysis, no report - -m earth radius multiplier - -f frequency for Fresnel zone calculation (MHz) - -R modify default range for -c or -L (miles/kilome- - ters) - -db maximum loss contour to display on path loss maps - (80-230 dB) - -nf do not plot Fresnel zones in height plots - -plo filename of path-loss output file - -pli filename of path-loss input file - -udt filename of user defined terrain input file - -geo generate a .geo georeference file (with .ppm out- - put) - -kml generate a Google Earth .kml file (for point-to- - point links) - -metric employ metric rather than imperial units for all - user I/O - - -IINNPPUUTT FFIILLEESS - SSPPLLAATT!! is a command-line driven application, and reads - input data through a number of data files. Some files are - mandatory for successful execution of the program, while - others are optional. Mandatory files include 3-arc second - topography models in the form of SPLAT Data Files (SDF - files), site location files (QTH files), and Longley-Rice - model parameter files (LRP files). Optional files include - city location files, cartographic boundary files, user- - defined terrain files, path-loss input files, and antenna - radiation pattern files. - -SSPPLLAATT DDAATTAA FFIILLEESS - SSPPLLAATT!! imports topographic data in the form of SPLAT Data - Files (SDFs). These files may be generated from a number - of information sources. In the United States, SPLAT Data - Files can be generated through U.S. Geological Survey - Digital Elevation Models (DEMs) using the uussggss22ssddff utility - included with SSPPLLAATT!!. USGS Digital Elevation Models com- - patible with this utility may be downloaded from: - _h_t_t_p_:_/_/_e_d_c_f_t_p_._c_r_._u_s_g_s_._g_o_v_/_p_u_b_/_d_a_t_a_/_D_E_M_/_2_5_0_/. - - Significantly better resolution and accuracy can be - obtained through the use of SRTM-3 Version 2 digital ele- - vation models. These models are the product of the STS-99 - Space Shuttle Radar Topography Mission, and are available - for most populated regions of the Earth. SPLAT Data Files - may be generated from SRTM data using the included - ssrrttmm22ssddff utility. SRTM-3 Version 2 data may be obtained - through anonymous FTP from: - _f_t_p_:_/_/_e_0_s_r_p_0_1_u_._e_c_s_._n_a_s_a_._g_o_v_:_2_1_/_s_r_t_m_/_v_e_r_s_i_o_n_2_/ - - Despite the higher accuracy that SRTM data has to offer, - some voids in the data sets exist. When voids are - detected, the ssrrttmm22ssddff utility replaces them with corre- - sponding data found in existing SDF files (that were pre- - sumably created from earlier USGS data through the - uussggss22ssddff utility). If USGS-derived SDF data is not avail- - able, voids are handled through adjacent pixel averaging, - or direct replacement. - - SPLAT Data Files contain integer value topographic eleva- - tions (in meters) referenced to mean sea level for - 1-degree by 1-degree regions of the earth with a resolu- - tion of 3-arc seconds. SDF files can be read in either - standard format (_._s_d_f) as generated by the uussggss22ssddff and - ssrrttmm22ssddff utilities, or in bzip2 compressed format - (_._s_d_f_._b_z_2). Since uncompressed files can be processed - slightly faster than files that have been compressed, - SSPPLLAATT!! searches for needed SDF data in uncompressed format - first. If uncompressed data cannot be located, SSPPLLAATT!! - then searches for data in bzip2 compressed format. If no - compressed SDF files can be found for the region - requested, SSPPLLAATT!! assumes the region is over water, and - will assign an elevation of sea-level to these areas. - - This feature of SSPPLLAATT!! makes it possible to perform path - analysis not only over land, but also between coastal - areas not represented by Digital Elevation Model data. - However, this behavior of SSPPLLAATT!! underscores the impor- - tance of having all the SDF files required for the region - being analyzed if meaningful results are to be expected. - -SSIITTEE LLOOCCAATTIIOONN ((QQTTHH)) FFIILLEESS - SSPPLLAATT!! imports site location information of transmitter - and receiver sites analyzed by the program from ASCII - files having a _._q_t_h extension. QTH files contain the - site's name, the site's latitude (positive if North of the - equator, negative if South), the site's longitude (in - degrees West, 0 to 360 degrees), and the site's antenna - height above ground level (AGL), each separated by a sin- - gle line-feed character. The antenna height is assumed to - be specified in feet unless followed by the letter _m or - the word _m_e_t_e_r_s in either upper or lower case. Latitude - and longitude information may be expressed in either deci- - mal format (74.6889) or degree, minute, second (DMS) for- - mat (74 41 20.0). - - For example, a site location file describing television - station WNJT, Trenton, NJ (_w_n_j_t_._q_t_h) might read as fol- - lows: - - WNJT - 40.2833 - 74.6889 - 990.00 - - Each transmitter and receiver site analyzed by SSPPLLAATT!! must - be represented by its own site location (QTH) file. - -LLOONNGGLLEEYY--RRIICCEE PPAARRAAMMEETTEERR ((LLRRPP)) FFIILLEESS - Longley-Rice parameter data files are required for SSPPLLAATT!! - to determine RF path loss in either point-to-point or area - prediction mode. Longley-Rice model parameter data is - read from files having the same base name as the transmit- - ter site QTH file, but with a format (_w_n_j_t_._l_r_p): - - 15.000 ; Earth Dielectric Constant (Relative per- - mittivity) - 0.005 ; Earth Conductivity (Siemens per meter) - 301.000 ; Atmospheric Bending Constant (N-units) - 700.000 ; Frequency in MHz (20 MHz to 20 GHz) - 5 ; Radio Climate (5 = Continental Temper- - ate) - 0 ; Polarization (0 = Horizontal, 1 = Verti- - cal) - 0.5 ; Fraction of situations (50% of loca- - tions) - 0.5 ; Fraction of time (50% of the time) - - If an LRP file corresponding to the tx_site QTH file can- - not be found, SSPPLLAATT!! scans the current working directory - for the file "splat.lrp". If this file cannot be found, - then the default parameters listed above will be assigned - by SSPPLLAATT!! and a corresponding "splat.lrp" file containing - this data will be written to the current working direc- - tory. "splat.lrp" can then be edited by the user as - needed. - - Typical Earth dielectric constants and conductivity values - are as follows: - - Dielectric Constant Conductiv- - ity - Salt water : 80 5.000 - Good ground : 25 0.020 - Fresh water : 80 0.010 - Marshy land : 12 0.007 - Farmland, forest : 15 0.005 - Average ground : 15 0.005 - Mountain, sand : 13 0.002 - City : 5 0.001 - Poor ground : 4 0.001 - - Radio climate codes used by SSPPLLAATT!! are as follows: - - 1: Equatorial (Congo) - 2: Continental Subtropical (Sudan) - 3: Maritime Subtropical (West coast of Africa) - 4: Desert (Sahara) - 5: Continental Temperate - 6: Maritime Temperate, over land (UK and west - coasts of US & EU) - 7: Maritime Temperate, over sea - - The Continental Temperate climate is common to large land - masses in the temperate zone, such as the United States. - For paths shorter than 100 km, there is little difference - between Continental and Maritime Temperate climates. - - The final two parameters in the _._l_r_p file correspond to - the statistical analysis provided by the Longley-Rice - model. In this example, SSPPLLAATT!! will return the maximum - path loss occurring 50% of the time (fraction of time) in - 50% of situations (fraction of situations). In the United - States, use a fraction of time parameter of 0.97 for digi- - tal television (8VSB modulation), or 0.50 for analog (VSB- - AM+NTSC) transmissions. - - For further information on these parameters, see: - _h_t_t_p_:_/_/_f_l_a_t_t_o_p_._i_t_s_._b_l_d_r_d_o_c_._g_o_v_/_i_t_m_._h_t_m_l and - _h_t_t_p_:_/_/_w_w_w_._s_o_f_t_w_r_i_g_h_t_._c_o_m_/_f_a_q_/_e_n_g_i_n_e_e_r_i_n_g_/_p_r_o_p___l_o_n_g_- - _l_e_y___r_i_c_e_._h_t_m_l - -CCIITTYY LLOOCCAATTIIOONN FFIILLEESS - The names and locations of cities, tower sites, or other - points of interest may be imported and plotted on topo- - graphic maps generated by SSPPLLAATT!!. SSPPLLAATT!! imports the - names of cities and locations from ASCII files containing - the location of interest's name, latitude, and longitude. - Each field is separated by a comma. Each record is sepa- - rated by a single line feed character. As was the case - with the _._q_t_h files, latitude and longitude information - may be entered in either decimal or degree, minute, second - (DMS) format. - - For example (_c_i_t_i_e_s_._d_a_t): - - Teaneck, 40.891973, 74.014506 - Tenafly, 40.919212, 73.955892 - Teterboro, 40.859511, 74.058908 - Tinton Falls, 40.279966, 74.093924 - Toms River, 39.977777, 74.183580 - Totowa, 40.906160, 74.223310 - Trenton, 40.219922, 74.754665 - - A total of five separate city data files may be imported - at a time, and there is no limit to the size of these - files. SSPPLLAATT!! reads city data on a "first come/first - served" basis, and plots only those locations whose anno- - tations do not conflict with annotations of locations read - earlier in the current city data file, or in previous - files. This behavior minimizes clutter in SSPPLLAATT!! gener- - ated topographic maps, but also mandates that important - locations be placed toward the beginning of the first city - data file, and locations less important be positioned fur- - ther down the list or in subsequent data files. - - City data files may be generated manually using any text - editor, imported from other sources, or derived from data - available from the U.S. Census Bureau using the cciittyyddee-- - ccooddeerr utility included with SSPPLLAATT!!. Such data is avail- - able free of charge via the Internet at: _h_t_t_p_:_/_/_w_w_w_._c_e_n_- - _s_u_s_._g_o_v_/_g_e_o_/_w_w_w_/_c_o_b_/_b_d_y___f_i_l_e_s_._h_t_m_l, and must be in ASCII - format. - -CCAARRTTOOGGRRAAPPHHIICC BBOOUUNNDDAARRYY DDAATTAA FFIILLEESS - Cartographic boundary data may also be imported to plot - the boundaries of cities, counties, or states on topo- - graphic maps generated by SSPPLLAATT!!. Such data must be of - the form of ARC/INFO Ungenerate (ASCII Format) Metadata - Cartographic Boundary Files, and are available from the - U.S. Census Bureau via the Internet at: - _h_t_t_p_:_/_/_w_w_w_._c_e_n_s_u_s_._g_o_v_/_g_e_o_/_w_w_w_/_c_o_b_/_c_o_2_0_0_0_._h_t_m_l_#_a_s_c_i_i and - _h_t_t_p_:_/_/_w_w_w_._c_e_n_s_u_s_._g_o_v_/_g_e_o_/_w_w_w_/_c_o_b_/_p_l_2_0_0_0_._h_t_m_l_#_a_s_c_i_i. A - total of five separate cartographic boundary files may be - imported at a time. It is not necessary to import state - boundaries if county boundaries have already been - imported. - -PPRROOGGRRAAMM OOPPEERRAATTIIOONN - SSPPLLAATT!! is invoked via the command-line using a series of - switches and arguments. Since SSPPLLAATT!! is a CPU and memory - intensive application, this type of interface minimizes - overhead and lends itself well to scripted (batch) opera- - tions. SSPPLLAATT!!'s CPU and memory scheduling priority may be - modified through the use of the Unix nniiccee command. - - The number and type of switches passed to SSPPLLAATT!! determine - its mode of operation and method of output data genera- - tion. Nearly all of SSPPLLAATT!!'s switches may be cascaded in - any order on the command line when invoking the program. - - SSPPLLAATT!! operates in two distinct modes: _p_o_i_n_t_-_t_o_-_p_o_i_n_t - _m_o_d_e, and _a_r_e_a _p_r_e_d_i_c_t_i_o_n _m_o_d_e. Either a line-of-sight - (LOS) or Longley-Rice Irregular Terrain (ITM) propagation - model may be invoked by the user. True Earth, four-thirds - Earth, or any other user-defined Earth radius may be spec- - ified when performing line-of-sight analysis. - -PPOOIINNTT--TTOO--PPOOIINNTT AANNAALLYYSSIISS - SSPPLLAATT!! may be used to perform line-of-sight terrain analy- - sis between two specified site locations. For example: - - splat -t tx_site.qth -r rx_site.qth - - invokes a line-of-sight terrain analysis between the - transmitter specified in _t_x___s_i_t_e_._q_t_h and receiver speci- - fied in _r_x___s_i_t_e_._q_t_h using a True Earth radius model, and - writes a SSPPLLAATT!! Obstruction Report to the current working - directory. The report contains details of the transmitter - and receiver sites, and identifies the location of any - obstructions detected along the line-of-sight path. If an - obstruction can be cleared by raising the receive antenna - to a greater altitude, SSPPLLAATT!! will indicate the minimum - antenna height required for a line-of-sight path to exist - between the transmitter and receiver locations specified. - Note that imperial units (miles, feet) are specified - unless the _-_m_e_t_r_i_c switch is added to SSPPLLAATT!!'s command - line options: - - splat -t tx_site.qth -r rx_site.qth -metric - - If the antenna must be raised a significant amount, this - determination may take a few moments. Note that the - results provided are the _m_i_n_i_m_u_m necessary for a line-of- - sight path to exist, and in the case of this simple exam- - ple, do not take Fresnel zone clearance requirements into - consideration. - - _q_t_h extensions are assumed by SSPPLLAATT!! for QTH files, and - are optional when specifying -t and -r arguments on the - command-line. SSPPLLAATT!! automatically reads all SPLAT Data - Files necessary to conduct the terrain analysis between - the sites specified. SSPPLLAATT!! searches for the required - SDF files in the current working directory first. If the - needed files are not found, SSPPLLAATT!! then searches in the - path specified by the _-_d command-line switch: - - splat -t tx_site -r rx_site -d /cdrom/sdf/ - - An external directory path may be specified by placing a - ".splat_path" file under the user's home directory. This - file must contain the full directory path of last resort - to all the SDF files. The path in the _$_H_O_M_E_/_._s_p_l_a_t___p_a_t_h - file must be of the form of a single line of ASCII text: - - /opt/splat/sdf/ - - and can be generated using any text editor. - - A graph of the terrain profile between the receiver and - transmitter locations as a function of distance from the - receiver can be generated by adding the _-_p switch: - - splat -t tx_site -r rx_site -p terrain_profile.png - - SSPPLLAATT!! invokes ggnnuupplloott when generating graphs. The file- - name extension specified to SSPPLLAATT!! determines the format - of the graph produced. _._p_n_g will produce a 640x480 color - PNG graphic file, while _._p_s or _._p_o_s_t_s_c_r_i_p_t will produce - postscript output. Output in formats such as GIF, Adobe - Illustrator, AutoCAD dxf, LaTeX, and many others are - available. Please consult ggnnuupplloott, and ggnnuupplloott's documen- - tation for details on all the supported output formats. - - A graph of elevations subtended by the terrain between the - receiver and transmitter as a function of distance from - the receiver can be generated by using the _-_e switch: - - splat -t tx_site -r rx_site -e elevation_profile.png - - The graph produced using this switch illustrates the ele- - vation and depression angles resulting from the terrain - between the receiver's location and the transmitter site - from the perspective of the receiver's location. A second - trace is plotted between the left side of the graph - (receiver's location) and the location of the transmitting - antenna on the right. This trace illustrates the eleva- - tion angle required for a line-of-sight path to exist - between the receiver and transmitter locations. If the - trace intersects the elevation profile at any point on the - graph, then this is an indication that a line-of-sight - path does not exist under the conditions given, and the - obstructions can be clearly identified on the graph at the - point(s) of intersection. - - A graph illustrating terrain height referenced to a line- - of-sight path between the transmitter and receiver may be - generated using the _-_h switch: - - splat -t tx_site -r rx_site -h height_profile.png - - A terrain height plot normalized to the transmitter and - receiver antenna heights can be obtained using the _-_H - switch: - - splat -t tx_site -r rx_site -H normalized_height_pro- - file.png - - A contour of the Earth's curvature is also plotted in this - mode. - - The first Fresnel Zone, and 60% of the first Fresnel Zone - can be added to height profile graphs by adding the _-_f - switch, and specifying a frequency (in MHz) at which the - Fresnel Zone should be modeled: - - splat -t tx_site -r rx_site -f 439.250 -H normal- - ized_height_profile.png - - A graph showing Longley-Rice path loss may be plotted - using the _-_l switch: - - splat -t tx_site -r rx_site -l path_loss_profile.png - - As before, adding the _-_m_e_t_r_i_c switch forces the graphs to - be plotted using metric units of measure. - - When performing path loss profiles, a Longley-Rice Model - Path Loss Report is generated by SSPPLLAATT!! in the form of a - text file with a _._l_r_o filename extension. The report con- - tains bearings and distances between the transmitter and - receiver, as well as the Longley-Rice path loss for vari- - ous distances between the transmitter and receiver loca- - tions. The mode of propagation for points along the path - are given as _L_i_n_e_-_o_f_-_S_i_g_h_t, _S_i_n_g_l_e _H_o_r_i_z_o_n, _D_o_u_b_l_e _H_o_r_i_- - _z_o_n, _D_i_f_f_r_a_c_t_i_o_n _D_o_m_i_n_a_n_t, and _T_r_o_p_o_s_c_a_t_t_e_r _D_o_m_i_n_a_n_t. - - To determine the signal-to-noise (SNR) ratio at remote - location where random Johnson (thermal) noise is the pri- - mary limiting factor in reception: - - _S_N_R=_T-_N_J-_L+_G-_N_F - - where TT is the ERP of the transmitter in dBW in the direc- - tion of the receiver, NNJJ is Johnson Noise in dBW (-136 dBW - for a 6 MHz television channel), LL is the path loss pro- - vided by SSPPLLAATT!! in dB (as a _p_o_s_i_t_i_v_e number), GG is the - receive antenna gain in dB over isotropic, and NNFF is the - receiver noise figure in dB. - - TT may be computed as follows: - - _T=_T_I+_G_T - - where TTII is actual amount of RF power delivered to the - transmitting antenna in dBW, GGTT is the transmitting - antenna gain (over isotropic) in the direction of the - receiver (or the horizon if the receiver is over the hori- - zon). - - To compute how much more signal is available over the min- - imum to necessary to achieve a specific signal-to-noise - ratio: - - _S_i_g_n_a_l__M_a_r_g_i_n=_S_N_R-_S - - where SS is the minimum required SNR ratio (15.5 dB for - ATSC (8-VSB) DTV, 42 dB for analog NTSC television). - - A topographic map may be generated by SSPPLLAATT!! to visualize - the path between the transmitter and receiver sites from - yet another perspective. Topographic maps generated by - SSPPLLAATT!! display elevations using a logarithmic grayscale, - with higher elevations represented through brighter shades - of gray. The dynamic range of the image is scaled between - the highest and lowest elevations present in the map. The - only exception to this is sea-level, which is represented - using the color blue. - - Topographic output is invoked using the _-_o switch: - - splat -t tx_site -r rx_site -o topo_map.ppm - - The _._p_p_m extension on the output filename is assumed by - SSPPLLAATT!!, and is optional. - - In this example, _t_o_p_o___m_a_p_._p_p_m will illustrate the loca- - tions of the transmitter and receiver sites specified. In - addition, the great circle path between the two sites will - be drawn over locations for which an unobstructed path - exists to the transmitter at a receiving antenna height - equal to that of the receiver site (specified in - _r_x___s_i_t_e_._q_t_h). - - It may desirable to populate the topographic map with - names and locations of cities, tower sites, or other - important locations. A city file may be passed to SSPPLLAATT!! - using the _-_s switch: - - splat -t tx_site -r rx_site -s cities.dat -o topo_map - - Up to five separate city files may be passed to SSPPLLAATT!! at - a time following the _-_s switch. - - County and state boundaries may be added to the map by - specifying up to five U.S. Census Bureau cartographic - boundary files using the _-_b switch: - - splat -t tx_site -r rx_site -b co34_d00.dat -o topo_map - - In situations where multiple transmitter sites are in use, - as many as four site locations may be passed to SSPPLLAATT!! at - a time for analysis: - - splat -t tx_site1 tx_site2 tx_site3 tx_site4 -r rx_site -p - profile.png - - In this example, four separate terrain profiles and - obstruction reports will be generated by SSPPLLAATT!!. A single - topographic map can be specified using the _-_o switch, and - line-of-sight paths between each transmitter and the - receiver site indicated will be produced on the map, each - in its own color. The path between the first transmitter - specified to the receiver will be in green, the path - between the second transmitter and the receiver will be in - cyan, the path between the third transmitter and the - receiver will be in violet, and the path between the - fourth transmitter and the receiver will be in sienna. - - SSPPLLAATT!! generated topographic maps are 24-bit TrueColor - Portable PixMap (PPM) images. They may be viewed, edited, - or converted to other graphic formats by popular image - viewing applications such as xxvv, TThhee GGIIMMPP, IImmaaggeeMMaaggiicckk, - and XXPPaaiinntt. PNG format is highly recommended for lossless - compressed storage of SSPPLLAATT!! generated topographic output - files. IImmaaggeeMMaaggiicckk's command-line utility easily converts - SSPPLLAATT!!'s PPM files to PNG format: - - convert splat_map.ppm splat_map.png - - Another excellent PPM to PNG command-line utility is - available at: - _h_t_t_p_:_/_/_w_w_w_._l_i_b_p_n_g_._o_r_g_/_p_u_b_/_p_n_g_/_b_o_o_k_/_s_o_u_r_c_e_s_._h_t_m_l. As a - last resort, PPM files may be compressed using the bzip2 - utility, and read directly by TThhee GGIIMMPP in this format. - -RREEGGIIOONNAALL CCOOVVEERRAAGGEE AANNAALLYYSSIISS - SSPPLLAATT!! can analyze a transmitter or repeater site, or net- - work of sites, and predict the regional coverage for each - site specified. In this mode, SSPPLLAATT!! can generate a topo- - graphic map displaying the geometric line-of-sight cover- - age area of the sites based on the location of each site - and the height of receive antenna wishing to communicate - with the site in question. SSPPLLAATT!! switches from point-to- - point analysis mode to area prediction mode when the _-_c - switch is invoked as follows: - - splat -t tx_site -c 30.0 -s cities.dat -b co34_d00.dat -o - tx_coverage - - In this example, SSPPLLAATT!! generates a topographic map called - _t_x___c_o_v_e_r_a_g_e_._p_p_m that illustrates the predicted line-of- - sight regional coverage of _t_x___s_i_t_e to receiving locations - having antennas 30.0 feet above ground level (AGL). If - the _-_m_e_t_r_i_c switch is used, the argument following the _-_c - switch is interpreted as being in meters, rather than in - feet. The contents of _c_i_t_i_e_s_._d_a_t are plotted on the map, - as are the cartographic boundaries contained in the file - _c_o_3_4___d_0_0_._d_a_t. - - When plotting line-of-sight paths and areas of regional - coverage, SSPPLLAATT!! by default does not account for the - effects of atmospheric bending. However, this behavior - may be modified by using the Earth radius multiplier (_-_m) - switch: - - splat -t wnjt -c 30.0 -m 1.333 -s cities.dat -b coun- - ties.dat -o map.ppm - - An earth radius multiplier of 1.333 instructs SSPPLLAATT!! to - use the "four-thirds earth" model for line-of-sight propa- - gation analysis. Any appropriate earth radius multiplier - may be selected by the user. - - When invoked in area prediction mode, SSPPLLAATT!! generates a - site report for each station analyzed. SSPPLLAATT!! site - reports contain details of the site's geographic location, - its height above mean sea level, the antenna's height - above mean sea level, the antenna's height above average - terrain, and the height of the average terrain calculated - in the directions of 0, 45, 90, 135, 180, 225, 270, and - 315 degrees azimuth. - -DDEETTEERRMMIINNIINNGG MMUULLTTIIPPLLEE RREEGGIIOONNSS OOFF LLOOSS CCOOVVEERRAAGGEE - SSPPLLAATT!! can also display line-of-sight coverage areas for - as many as four separate transmitter sites on a common - topographic map. For example: - - splat -t site1 site2 site3 site4 -c 10.0 -metric -o net- - work.ppm - - plots the regional line-of-sight coverage of site1, site2, - site3, and site4 based on a receive antenna located 10.0 - meters above ground level. A topographic map is then - written to the file _n_e_t_w_o_r_k_._p_p_m. The line-of-sight cover- - age area of the transmitters are plotted as follows in the - colors indicated (along with their corresponding RGB val- - ues in decimal): - - site1: Green (0,255,0) - site2: Cyan (0,255,255) - site3: Medium Violet (147,112,219) - site4: Sienna 1 (255,130,71) - - site1 + site2: Yellow (255,255,0) - site1 + site3: Pink (255,192,203) - site1 + site4: Green Yellow (173,255,47) - site2 + site3: Orange (255,165,0) - site2 + site4: Dark Sea Green 1 (193,255,193) - site3 + site4: Dark Turquoise (0,206,209) - - site1 + site2 + site3: Dark Green (0,100,0) - site1 + site2 + site4: Blanched Almond (255,235,205) - site1 + site3 + site4: Medium Spring Green (0,250,154) - site2 + site3 + site4: Tan (210,180,140) - - site1 + site2 + site3 + site4: Gold2 (238,201,0) - - If separate _._q_t_h files are generated, each representing a - common site location but a different antenna height, a - single topographic map illustrating the regional coverage - from as many as four separate locations on a single tower - may be generated by SSPPLLAATT!!. - -LLOONNGGLLEEYY--RRIICCEE PPAATTHH LLOOSSSS AANNAALLYYSSIISS - If the _-_c switch is replaced by a _-_L switch, a Longley- - Rice path loss map for a transmitter site may be gener- - ated: - - splat -t wnjt -L 30.0 -s cities.dat -b co34_d00.dat -o - path_loss_map - - In this mode, SSPPLLAATT!! generates a multi-color map illus- - trating expected signal levels (path loss) in areas sur- - rounding the transmitter site. A legend at the bottom of - the map correlates each color with a specific path loss - range in decibels. - - The Longley-Rice analysis range may be modified to a user- - specific value using the _-_R switch. The argument must be - given in miles (or kilometers if the _-_m_e_t_r_i_c switch is - used). If a range wider than the generated topographic - map is specified, SSPPLLAATT!! will perform Longley-Rice path - loss calculations between all four corners of the area - prediction map. - - The _-_d_b switch allows a constraint to be placed on the - maximum path loss region plotted on the map. A maximum - path loss between 80 and 230 dB may be specified using - this switch. For example, if a path loss beyond -140 dB - is irrelevant to the survey being conducted, SSPPLLAATT!!'s path - loss plot can be constrained to the region bounded by the - 140 dB attenuation contour as follows: - - splat -t wnjt -L 30.0 -s cities.dat -b co34_d00.dat -db - 140 -o plot.ppm - - -AANNTTEENNNNAA RRAADDIIAATTIIOONN PPAATTTTEERRNN PPAARRAAMMEETTEERRSS - Normalized field voltage patterns for a transmitting - antenna's horizontal and vertical planes are imported - automatically into SSPPLLAATT!! when a Longley-Rice coverage - analysis is performed. Antenna pattern data is read from - a pair of files having the same base name as the transmit- - ter and LRP files, but with _._a_z and _._e_l extensions for - azimuth and elevation pattern files, respectively. Speci- - fications regarding pattern rotation (if any) and - mechanical beam tilt and tilt direction (if any) are also - contained within SSPPLLAATT!! antenna pattern files. - - For example, the first few lines of a SSPPLLAATT!! azimuth pat- - tern file might appear as follows (_k_v_e_a_._a_z): - - 183.0 - 0 0.8950590 - 1 0.8966406 - 2 0.8981447 - 3 0.8995795 - 4 0.9009535 - 5 0.9022749 - 6 0.9035517 - 7 0.9047923 - 8 0.9060051 - - The first line of the _._a_z file specifies the amount of - azimuthal pattern rotation (measured clockwise in degrees - from True North) to be applied by SSPPLLAATT!! to the data con- - tained in the _._a_z file. This is followed by azimuth head- - ings (0 to 360 degrees) and their associated normalized - field patterns (0.000 to 1.000) separated by whitespace. - - The structure of SSPPLLAATT!! elevation pattern files is - slightly different. The first line of the _._e_l file speci- - fies the amount of mechanical beam tilt applied to the - antenna. Note that a _d_o_w_n_w_a_r_d _t_i_l_t (below the horizon) is - expressed as a _p_o_s_i_t_i_v_e _a_n_g_l_e, while an _u_p_w_a_r_d _t_i_l_t (above - the horizon) is expressed as a _n_e_g_a_t_i_v_e _a_n_g_l_e. This data - is followed by the azimuthal direction of the tilt, sepa- - rated by whitespace. - - The remainder of the file consists of elevation angles and - their corresponding normalized voltage radiation pattern - (0.000 to 1.000) values separated by whitespace. Eleva- - tion angles must be specified over a -10.0 to +90.0 degree - range. As was the convention with mechanical beamtilt, - _n_e_g_a_t_i_v_e _e_l_e_v_a_t_i_o_n _a_n_g_l_e_s are used to represent elevations - _a_b_o_v_e _t_h_e _h_o_r_i_z_o_n, while _p_o_s_i_t_i_v_e _a_n_g_l_e_s represents eleva- - tions _b_e_l_o_w _t_h_e _h_o_r_i_z_o_n. - - For example, the first few lines a SSPPLLAATT!! elevation pat- - tern file might appear as follows (_k_v_e_a_._e_l): - - 1.1 130.0 - -10.0 0.172 - -9.5 0.109 - -9.0 0.115 - -8.5 0.155 - -8.0 0.157 - -7.5 0.104 - -7.0 0.029 - -6.5 0.109 - -6.0 0.185 - - In this example, the antenna is mechanically tilted down- - ward 1.1 degrees towards an azimuth of 130.0 degrees. - - For best results, the resolution of azimuth pattern data - should be specified to the nearest degree azimuth, and - elevation pattern data resolution should be specified to - the nearest 0.01 degrees. If the pattern data specified - does not reach this level of resolution, SSPPLLAATT!! will - interpolate the values provided to determine the data at - the required resolution, although this may result in a - loss in accuracy. - - -IIMMPPOORRTTIINNGG AANNDD EEXXPPOORRTTIINNGG RREEGGIIOONNAALL PPAATTHH LLOOSSSS CCOONNTTOOUURR DDAATTAA - Performing a Longley-Rice coverage analysis can be a very - time consuming process, especially if the analysis is - repeated repeatedly to discover what effects changes to - the antenna radiation patterns make to the predicted cov- - erage area. - - This process can be expedited by exporting the Longley- - Rice regional path loss contour data to an output file, - modifying the path loss data externally to incorporate - antenna pattern effects, and then importing the modified - path loss data back into SSPPLLAATT!! to rapidly produce a - revised path loss map. - - For example, a path loss output file can be generated by - SSPPLLAATT!! for a receive site 30 feet above ground level over - a 50 mile radius surrounding a transmitter site to a maxi- - mum path loss of 140 dB using the following syntax: - - splat -t kvea -L 30.0 -R 50.0 -db 140 -plo pathloss.dat - - SSPPLLAATT!! path loss output files often exceed 100 megabytes - in size. They contain information relating to the bound- - aries of region they describe followed by latitudes - (degrees North), longitudes (degrees West), azimuths, ele- - vations (to the first obstruction), and path loss figures - (dB) for a series of specific points that comprise the - region surrounding the transmitter site. The first few - lines of a SSPPLLAATT!! path loss output file take on the fol- - lowing appearance (_p_a_t_h_l_o_s_s_._d_a_t): - - 119, 117 ; max_west, min_west - 35, 33 ; max_north, min_north - 34.2265434, 118.0631104, 48.171, -37.461, 67.70 - 34.2270355, 118.0624390, 48.262, -26.212, 73.72 - 34.2280197, 118.0611038, 48.269, -14.951, 79.74 - 34.2285156, 118.0604401, 48.207, -11.351, 81.68 - 34.2290077, 118.0597687, 48.240, -10.518, 83.26 - 34.2294998, 118.0591049, 48.225, 23.201, 84.60 - 34.2304878, 118.0577698, 48.213, 15.769, 137.84 - 34.2309799, 118.0570984, 48.234, 15.965, 151.54 - 34.2314720, 118.0564346, 48.224, 16.520, 149.45 - 34.2319679, 118.0557632, 48.223, 15.588, 151.61 - 34.2329521, 118.0544281, 48.230, 13.889, 135.45 - 34.2334442, 118.0537643, 48.223, 11.693, 137.37 - 34.2339401, 118.0530930, 48.222, 14.050, 126.32 - 34.2344322, 118.0524292, 48.216, 16.274, 156.28 - 34.2354164, 118.0510941, 48.222, 15.058, 152.65 - 34.2359123, 118.0504227, 48.221, 16.215, 158.57 - 34.2364044, 118.0497589, 48.216, 15.024, 157.30 - 34.2368965, 118.0490875, 48.225, 17.184, 156.36 - - It is not uncommon for SSPPLLAATT!! path loss files to contain - as many as 3 million or more lines of data. Comments can - be placed in the file if they are proceeded by a semicolon - character. The vviimm text editor has proven capable of - editing files of this size. - - Note as was the case in the antenna pattern files, nega- - tive elevation angles refer to upward tilt (above the - horizon), while positive angles refer to downward tilt - (below the horizon). These angles refer to the elevation - to the receiving antenna at the height above ground level - specified using the _-_L switch _i_f the path between trans- - mitter and receiver is unobstructed. If the path between - the transmitter and receiver is obstructed, then the ele- - vation angle to the first obstruction is returned by - SSPPLLAATT!!. This is because the Longley-Rice model considers - the energy reaching a distant point over an obstructed - path as a derivative of the energy scattered from the top - of the first obstruction, only. Since energy cannot reach - the obstructed location directly, the actual elevation - angle to that point is irrelevant. - - When modifying SSPPLLAATT!! path loss files to reflect antenna - pattern data, _o_n_l_y _t_h_e _l_a_s_t _c_o_l_u_m_n _(_p_a_t_h _l_o_s_s_) should be - amended to reflect the antenna's normalized gain at the - azimuth and elevation angles specified in the file. (At - this time, programs and scripts capable of performing this - operation are left as an exercise for the user.) - - Modified path loss maps can be imported back into SSPPLLAATT!! - for generating revised coverage maps: - - splat -t kvea -pli pathloss.dat -s city.dat -b county.dat - -o map.ppm - - SSPPLLAATT!! path loss files can also be used for conducting - coverage or interference studies outside of SSPPLLAATT!!. - -UUSSEERR--DDEEFFIINNEEDD TTEERRRRAAIINN IINNPPUUTT FFIILLEESS - A user-defined terrain file is a user-generated text file - containing latitudes, longitudes, and heights above ground - level of specific terrain features believed to be of - importance to the SSPPLLAATT!! analysis being conducted, but - noticeably absent from the SDF files being used. A user- - defined terrain file is imported into a SSPPLLAATT!! analysis - using the _-_u_d_t switch: - - splat -t tx_site -r rx_site -udt udt_file.txt -o map.ppm - - A user-defined terrain file has the following appearance - and structure: - - 40.32180556, 74.1325, 100.0 meters - 40.321805, 74.1315, 300.0 - 40.3218055, 74.1305, 100.0 meters - - Terrain height is interpreted as being described in feet - above ground level unless followed by the word _m_e_t_e_r_s, and - is added _o_n _t_o_p _o_f the terrain specified in the SDF data - for the locations specified. Be aware that each user- - defined terrain feature specified will be interpreted as - being 3-arc seconds in both latitude and longitude. Fea- - tures described in the user-defined terrain file that - overlap previously defined features in the file are - ignored by SSPPLLAATT!!. - -SSIIMMPPLLEE TTOOPPOOGGRRAAPPHHIICC MMAAPP GGEENNEERRAATTIIOONN - In certain situations it may be desirable to generate a - topographic map of a region without plotting coverage - areas, line-of-sight paths, or generating obstruction - reports. There are several ways of doing this. If one - wishes to generate a topographic map illustrating the - location of a transmitter and receiver site along with a - brief text report describing the locations and distances - between the sites, the _-_n switch should be invoked as fol- - lows: - - splat -t tx_site -r rx_site -n -o topo_map.ppm - - If no text report is desired, then the _-_N switch is used: - - splat -t tx_site -r rx_site -N -o topo_map.ppm - - If a topographic map centered about a single site out to a - minimum specified radius is desired instead, a command - similar to the following can be used: - - splat -t tx_site -R 50.0 -s NJ_Cities -b NJ_Counties -o - topo_map.ppm - - where -R specifies the minimum radius of the map in miles - (or kilometers if the _-_m_e_t_r_i_c switch is used). - - If the _-_o switch and output filename are omitted in these - operations, topographic output is written to a file named - _m_a_p_._p_p_m in the current working directory by default. - -GGEEOORREEFFEERREENNCCEE FFIILLEE GGEENNEERRAATTIIOONN - Topographic, coverage (_-_c), and path loss contour (_-_L) - maps generated by SSPPLLAATT!! may be imported into XXaassttiirr (X - Amateur Station Tracking and Information Reporting) soft- - ware by generating a georeference file using SSPPLLAATT!!'s _-_g_e_o - switch: - - splat -t kd2bd -R 50.0 -s NJ_Cities -b NJ_Counties -geo -o - map.ppm - - The georeference file generated will have the same base - name as the _-_o file specified, but have a _._g_e_o extension, - and permit proper interpretation and display of SSPPLLAATT!!'s - .ppm graphics in XXaassttiirr software. - -GGOOOOGGLLEE MMAAPP KKMMLL FFIILLEE GGEENNEERRAATTIIOONN - Keyhole Markup Language files compatible with GGooooggllee EEaarrtthh - may be generated by SSPPLLAATT!! when performing point-to-point - analyses by invoking the _-_k_m_l switch: - - splat -t wnjt -r kd2bd -kml - - The KML file generated will have the same filename struc- - ture as an Obstruction Report for the transmitter and - receiver site names given, except it will carry a _._k_m_l - extension. - - Once loaded into GGooooggllee EEaarrtthh (File --> Open), the KML - file will annotate the map display with the names of the - transmitter and receiver site locations. The viewpoint of - the image will be from the position of the transmitter - site looking towards the location of the receiver. The - point-to-point path between the sites will be displayed as - a white line while the RF line-of-sight path will be dis- - played in green. GGooooggllee EEaarrtthh's navigation tools allow - the user to "fly" around the path, identify landmarks, - roads, and other featured content. - -DDEETTEERRMMIINNAATTIIOONN OOFF AANNTTEENNNNAA HHEEIIGGHHTT AABBOOVVEE AAVVEERRAAGGEE TTEERRRRAAIINN - SSPPLLAATT!! determines antenna height above average terrain - (HAAT) according to the procedure defined by Federal Com- - munications Commission Part 73.313(d). According to this - definition, terrain elevations along eight radials between - 2 and 10 miles (3 and 16 kilometers) from the site being - analyzed are sampled and averaged for each 45 degrees of - azimuth starting with True North. If one or more radials - lie entirely over water or over land outside the United - States (areas for which no USGS topography data is avail- - able), then those radials are omitted from the calculation - of average terrain. - - Note that SRTM elevation data, unlike older 3-arc second - USGS data, extends beyond the borders of the United - States. Therefore, HAAT results may not be in full com- - pliance with FCC Part 73.313(d) in areas along the borders - of the United States if the SDF files used by SSPPLLAATT!! are - SRTM-derived. - - When performing point-to-point terrain analysis, SSPPLLAATT!! - determines the antenna height above average terrain only - if enough topographic data has already been loaded by the - program to perform the point-to-point analysis. In most - cases, this will be true, unless the site in question does - not lie within 10 miles of the boundary of the topography - data in memory. - - When performing area prediction analysis, enough topogra- - phy data is normally loaded by SSPPLLAATT!! to perform average - terrain calculations. Under such conditions, SSPPLLAATT!! will - provide the antenna height above average terrain as well - as the average terrain above mean sea level for azimuths - of 0, 45, 90, 135, 180, 225, 270, and 315 degrees, and - include such information in the generated site report. If - one or more of the eight radials surveyed fall over water, - or over regions for which no SDF data is available, SSPPLLAATT!! - reports _N_o _T_e_r_r_a_i_n for the radial paths affected. - -RREESSTTRRIICCTTIINNGG TTHHEE MMAAXXIIMMUUMM SSIIZZEE OOFF AANN AANNAALLYYSSIISS RREEGGIIOONN - SSPPLLAATT!! reads SDF files as needed into a series of memory - pages or "slots" within the structure of the program. - Each "slot" holds one SDF file representing a one degree - by one degree region of terrain. A _#_d_e_f_i_n_e _M_A_X_S_L_O_T_S - statement in the first several lines of _s_p_l_a_t_._c_p_p sets the - maximum number of "slots" available for holding topography - data. It also sets the maximum size of the topographic - maps generated by SSPPLLAATT!!. MAXSLOTS is set to 9 by - default. If SSPPLLAATT!! produces a segmentation fault on - start-up with this default, it is an indication that not - enough RAM and/or virtual memory (swap space) is available - to run SSPPLLAATT!! with the number of MAXSLOTS specified. In - situations where available memory is low, MAXSLOTS may be - reduced to 4 with the understanding that this will greatly - limit the maximum region SSPPLLAATT!! will be able to analyze. - If 118 megabytes or more of total memory (swap space plus - RAM) is available, then MAXSLOTS may be increased to 16. - This will permit operation over a 4-degree by 4-degree - region, which is sufficient for single antenna heights in - excess of 10,000 feet above mean sea level, or point-to- - point distances of over 1000 miles. - -AADDDDIITTIIOONNAALL IINNFFOORRMMAATTIIOONN - The latest news and information regarding SSPPLLAATT!! software - is available through the official SSPPLLAATT!! software web page - located at: _h_t_t_p_:_/_/_w_w_w_._q_s_l_._n_e_t_/_k_d_2_b_d_/_s_p_l_a_t_._h_t_m_l. - -AAUUTTHHOORRSS - John A. Magliacane, KD2BD <_k_d_2_b_d_@_a_m_s_a_t_._o_r_g> - Creator, Lead Developer - - Doug McDonald <_m_c_d_o_n_a_l_d_@_s_c_s_._u_i_u_c_._e_d_u> - Longley-Rice Model integration - - Ron Bentley <_r_o_n_b_e_n_t_l_e_y_@_e_a_r_t_h_l_i_n_k_._n_e_t> - Fresnel Zone plotting and clearance determination - - - - -KD2BD Software 20 December 2006 SPLAT!(1)