Documentation



VisualCallSign

The VisualCallSign tool allows you to enter one or more valid/active callsigns and visually display locations ( transmitters ) as well as mobile radius-area-of-operation. Callsigns must be separated by a comma ( , ).

You can hover over the nodes in the treeview displayed and click-through to the FCC ULS License page for the call sign.

Treenodes that contain location information will allow you to click-through and perform a radius search for that specific asset on the call sign -- this allows you to display entities that are licensed in close proximity of your call sign's asset. Note: The radius-search ( VisualSpectrumFinder ) tool will display the assets of the call sign under study as well as other call signs.



VisualElevationHaatDistanceAzimuth

The VisualElevationHaatDistanceAzimuth tool is truly a simple point and double-click operation. To obtain information about any point in North America just zoom and pan to the location using the powerful features of GooleMaps and double-click the location for which you desire to obtain its elevation (AMSL) and HAAT.

Once you have point marked on the map pan to another location and double-click again. You will now have a second point's elevation and HAAT as well as the relationship with the first point you marked, i.e., you will be provided with the distance and azimuth between the two points. The first point marked is the From-point and the second point marked is the To-Point.

You can continue to double-click away and place mark as many points on the map as desired. Want to start over? Hit the Clear button.



VisualHaat

The VisualHaat tool is truly a simple point and double-click operation. To obtain information about any point in North America CONUS/AK/HI -- just zoom and pan to the location using the powerful features of GooleMaps and double-click the location for which you desire to obtain its HAAT. Once you mark your point, it's latitude and longitude are determined and displayed. You can now enter the ground elevation and antenna height of the site as is prescribed by FCC at HAAT Calculator and hit the submit button to get the true HAAT.

Note: This tool computes HAAT by measuring the ground elevation on eight (8) uniform radial segments from 3-16 km. The FCC has prescribed several interpretations for HAAT ( FM Broadcast, TV, DTV, Land-Mobile, etc. ). This VisualHaat tool defaults to the Land-Mobile model as specified in the FCC's HAAT Calculator and 47 CFR [FCC] 24.53. Oh yes, rumor has it that when the FCC converted its NAD27 elevation data to the NAD83/WGS84 coordinate system, they suffered programming/translation errors ( integer truncation, instead of proper floating point rounding ) in the conversion. At point elevation calculations were “a bit off…” – just a rumor.

The really cool thing about the VisualHaat tool is that you can zoom-in to see exactly what values where used to deduce the final HAAT outcome. Ready to see another HAAT calculation, just zoom/pan and double-click again.

The AverageElevationMeters is the same as HAAT but it does not account for the antenna hight.

The Visual HAAT tool makes the following assumptions:

  • All coordinates are specified assuming a coordinate system of NAD83.
  • All input and output distance measures are metric ( meters, kilometers ).
  • Only coordinates in the CONUS ( +HI/AK/PR ) are useable; coordinates specified outside the CONUS will result in a processing error.
  • HAAT calculations strictly follow 47 CFR 24.53; eight radials at ( 0, 45, 90, 135, 180, 225, 270, 315 ) degrees; each radial measures a segment from [3.. 16] km on the radial; 50 evenly spaced data points is where terrain elevation is collected for the segment.
  • The Earth is an ellipsoid, radials are not straight lines, they are arc-segments; azimuth and direction are calculated as such.
  • The terrain elevation database used for Elevaton and HAAT calculations is the USGS 1 arc-second National Elevation Dataset (NED); which yeilds a distinct elevation about every ~30 meters ( ~100 feet ).
  • The tool will emit Remarks, Warnings, and Errors. Warnings require attention but not necessarily reaction. Errors are fatal and do require a reaction. Remarks are FYI.
  • Should you need to specify how the HAAT calculation is performed, e.g., the number of radials, the number of points on a radial, the segment length of the radial, you can do that too by using the BatchSubmissionTool that will allow you to exactly specify how the HAAT is to be deduced.

    The ViusalHaat tool can be used in two (2) modes:

  • User Interactive where you fill in the required parameters and submit your study.
  • Batch See the BatchSubmissionTool that will allow you to submit an Excel workbook to perform the VisualHaat analysis in batch mode.


  • VisualMaximumErpWatts

    The VisualMaximumErpWatts tool allows you to zoom to a map location, double-click to select the location, and obtain the maximum allowable ERP ( Effective Radiated Power ) in Watts that is allowed by FCC rules. The FCC rules that govern this depend on the AntennaHeightMeters, AntennaHaatMeters, AntennaElevationMeters, and possibly the required ServiceRadiusKm.

    Once you have selected your location, then specify the frequency, antenna height, and service radius -- then click the "Submit Study" button and your results will be presented.

    The results also offer a "ViusalCoverageUrl" that will allow you to immediately request a coverage map and the service/interference contours for the allowed ERP at your selected location. Very cool.

    This tool will allow you to determine the MaximumErpWatts in the following bands:

  • [ 000.0 .. 025.0 MHz ][ 47 CFR 90.205 ]
  • [ 025.0 .. 050.0 MHz ][ 47 CFR 90.205 ]
  • [ 072.0 .. 076.0 MHz ][ 47 CFR 90.205 ]
  • [ 150.0 .. 174.0 MHz ][ 47 CFR 90.205 ]
  • [ 217.0 .. 220.0 MHz ][ 47 CFR 90.259 ]
  • [ 220.0 .. 222.0 MHz ][ 47 CFR 90.729 ]
  • [ 421.0 .. 430.0 MHz ][ 47 CFR 90.279 ]
  • [ 450.0 .. 470.0 MHz ][ 47 CFR 90.205 ]
  • [ 769.0 .. 775.0 MHz ][ 47 CFR 90.531 ]
  • [ 799.0 .. 805.0 MHz ][ 47 CFR 90.531 ]
  • [ 806.0 .. 824.0, 896.0 .. 901.0 MHz ][ 47 CFR 90.635 ]
  • [ 851.0 .. 869.0, 935.0 .. 940.0 MHz ][ 47 CFR 90.635 ]
  • [ 902.0 .. 927.0 MHz ][ 47 CFR 90.353 ]
  • [ 927.0 .. 928.0 MHz ][ 47 CFR 90.353 ]
  • [ 929.0 .. 930.0 MHz ][ 47 CFR 90.494 ]
  • You have the option to display the Antenna HAAT Profile that enumerates the radials, and the respective elevations there on.

    You have the option to display “High Sites” in WA and CA to see if special conditions map apply per FCC 47 CFR 90.621.

    You have the option to display FCC "Quiet Zones" ( 47 CFR 0.121 and 47 CFR 1.924 ) that will allow you determine if you should be mindful operating in or near them. The tool does not automatically warn or de-rate the maximum allowable ERP if you are operating in or near a quiet zone – there are just too many convoluted specifications in the rules to attempt that deduction. For example, some of the quiet zones allow you to operate but at a specific power at a specific frequency, and possibly require that you “coordinate” with the entity listening in the quiet zone for definitive permission.

    There are more quiet zones in the US than are specified by the FCC rules, you should also check out the list maintained in World Radio Telescopes And Radio Quiet Zones. which will use GoogleMaps.



    VisualDhaat

    See VisualShortSpacing.



    ViusalShortSpacing

    The VisualShortSpacing tool compiles with the 47 CFR [FCC] 90.621 rule to deduce allowed short spacing for a proposed transmitting station that is less than 113 km from an incumbent/existing receiving station. In a nutshell, you can:

  • short space down to 88 km if you satisfy the power, antenna height, and terrain requirements of 47 CFR [FCC] 90.621 .
  • short space down to 144 (88 + 56) km if either the proposed and/or existing location is considered a "high-site" in WA or Southern CA and satisfy the power, antenna height, and terrain requirements of 47 CFR [FCC] 90.621 a . This gets a little complicated but VisualShortSpacing will figure it out for you!

    Separations for stations on Santiago Peak, Sierra Peak, Mount Lukens, and Mount Wilson (CA) and the locations in the State of Washington listed in paragraph 47 CFR 90.621 (b)(3) are ** 56 km (35 mi) ** greater than those listed in the Short-Spacing Separation Table [47 CFR 90.621 (b)(4)(ii)(C)]. In the event of conflict between this table and the table of additional California high elevation sites shown in paragraph 47 CFR 90.621 (b)(2), the latter will apply.

    Separations for stations on Santiago Peak, Sierra Peak, Mount Lukens, and Mount Wilson (CA) 47 CFR 90.621 (b)(1) and the locations in the State of Washington listed in paragraph 47 CFR 90.621 (b)(3), except as indicated in paragraph 47 CFR 90.621 (b)(4), incumbent licensees in Channel Blocks F1 through V that have received the consent of all affected parties or a certified frequency coordinator to utilize an 18 dBμV/m signal strength interference contour, have been granted channel exclusivity and shall be separated from co-channel stations by a minimum of ** 229 km (142 mi) **.

    Locations within one mile (1.6 km) of the geographical coordinates listed in the table [47 CFR 90.6221 (b)(3)] as well as Santiago Peak, Sierra Peak, Mount Lukens, and Mount Wilson will be considered to be at that site.


  • This tool must compute two sets of three DHAAT calculations, three for the proposed transmitter and three for the existing/incumbent receiver. All the deductions that are required to calculate short spacing are produced in the results (e.g., DHAAT, Azimuth, Distance between, etc.)

    One thing to be mindful of is the user specified ground elevation. If the proposed and/or existing ground elevation differs significantly from the ground elevation in the elevation dataset ( USGS NED one arc-second ) you will be warned in the "Processing Warnings" field. Make the appropriate adjustment if you don't trust the user value(s) originally provided for ground elevation(s).

    The Visual ShortSpacing tool makes the following assumptions:

  • All coordinates are specified assuming a coordinate system of NAD83.
  • All frequencies are specified in MHz.
  • All input and output distance measures are metric ( meters, kilometers ).
  • Only coordinates in the CONUS are useable; coordinates specified outside the CONUS will result in a processing error.
  • HAAT calculations strictly follow 47 CFR 24.53; eight radials at ( 0, 45, 90, 135, 180, 225, 270, 315 ) degrees; each radial measures a segment from [ 3 .. 16 ] km on the radial; 50 evenly spaced data points is where terrain elevation is collected for the segment.
  • Where referenced, ATE is Average Terrain Elevation in meters. It essentially is HAAT with the ( GroundElevationMeters + AntennaHeightMeters ) factored out.
  • DHAAT calculations strictly follow 47 CFR 90.621; three radials ( -15, 0, +15 ) degrees are used, the zero (0) radial is on the arc between the specified existing and proposed coordinates; each raidal measures a segment from [3..16] km on the radial; 50 evenly spaced points is where the HAAT is collected on the segement.
  • Although 47 CFR 90.621 (b)[1][2][3] specifies that high sites operating in channel blocks F1 through V in Northern and Southern California as well as Washington State have specific co-channel separation requirements of 229 km when operating with a sanctioned ( by all affected co-channel licensees and/or by a frequency coordinator ) 18 dBμV/m signal strength interference contour, the tool does not attempt to deduce such a relationship. The tool does, however, emit a warning if either the existing and/or proposed assets are at a high site; when warned, further analysis beyond the scope of this tool is warranted.
  • The Earth is an ellipsoid, radials are not straight lines, they are arc-segments; azimuth and direction is calculated as such.
  • The terrain elevation database used for Elevaton and HAAT calculations is the USGS 1/3 arc-second National Elevation Dataset; which yeilds a distinct elevation about every 30 meters ( 100 feet ). A 3 arc-second database yeilds a distinct elevation about every 270 meters ( 888 feet ).
  • The tool will emit Remarks, Warnings, and Errors. Warnings require attention but not necessarily reaction. Errors are fatal and do require a reaction. Remarks are FYI.
  • The ViusalShortSpacing tool can be used in three (3) modes:

  • User Interactive where you fill in the required parameters and submit your study.
  • URL Argument where you specify the required parameters in a URL. This allows users to pre-stage and record their inquires using well-known applications such as Microsoft Excel or Word and get deterministic reproducible results by just clicking on a link. If you maintain your links in an Excel spreadsheet, you can copy/paste the results to the same spreadsheet.

    For example, do a Shift-Left-Click on this example URL. To paste the example URL to your Excel workbook or Word document, just right click on it and copy the link address, then paste as needed.

  • Batch See the BatchSubmissionTool that will allow you to submit an Excel workbook to perform the VisualShortSpaciing analysis in batch mode. This mode will allow you to specify how the DHAAT radials are calculated. It also provides intermediate values such as DHAAT, azimuths, power band, etc. so you can verify the results using the FCC's short spacing table.


  • VisualContour

    The VisualContour tool is used to plot the service and interference contours for a proposed and existing location. It is very similar to the VisualShortSpacing tool, except it displays coverage on 72 ( 360/5 ) different radials where as the ViusalShortSpacing tool only uses the three (3) DHAAT radials specified in 47 CFR [FCC] 90.621 to deduce its result.

    The specifications for calculating the service and interference contours rely on some rather primitive rules – which assumed that the planning engineer had a slide-rule, a protractor, FCC provided chart(s), and paper topographical maps from the USGS. It is suggested that you utilize the VisualCoverage tool to see a better view of the service area. The VisualCoverage tool assumes the planning engineer has a computer, a digital representation of elevations, and a graphic display.

    The following parameters may be specified for both the proposed and the existing/incumbent locations:

  • CallSign (optional)
  • LocationNumber (optional)
  • FrequencyMHz (optional)
  • Latitude ( Decimal and/or DMS )
  • Longitude ( Decimal and/or DMS )
  • ElevatonMeters
  • AntennaHightMeters
  • ErpWatts
  • The tool is simple in nature in that it only allows you to map contours for a proposed transmitter and one incumbent/existing transmitter.

    You must remain mindful to select the correct contour type which is frequency dependent. This tool does not automatically select the service contour type, as there are multiple contours types are applicable for some frequency bands -- depending on which FCC rules you desire to follow.

    The following contour types are supported:

  • [ 0 ] : R-6602 VHF LOW [030-050 MHz] :: Service: 31 dBµ F(50,50) / Interference: 13 dBµ F(50,10)
  • [ 1 ] : R-6602 VHF HIGH [150-174 MHz] :: Service: 37 dBµ F(50,50) / Interference: 19 dBµ F(50,10)
  • [ 2 ] : R-6602 UHF LOW [421-512 MHz] :: Service: 39 dBµ F(50,50) / Interference: 21 dBµ F(50,10)
  • [ 3 ] : R-6602 UHF HIGH [698-862 MHz] :: Service: 40 dBµ:F(50,50) / Interference: 22 dBµ F(50,10)
  • [ 4 ] : FCC 22.567 VHF HIGH [150-174 MHz]
  • [ 5 ] : FCC 22.567 UHF LOW [421-512 MHz]
  • The ViusalContour tool can be used in three (3) modes:

  • User Interactive where you fill in the required parameters and submit your study.
  • URL Argument where you specify the required parameters in a URL. This allows users to pre-stage and record their inquires using well-known applications such as Microsoft Excel or Word and get deterministic reproducible results by just clicking on a link. If you maintain your links in an Excel spreadsheet, you can copy/paste the results to the same spreadsheet.

    For example, do a Shift-Left-Click on this example URL. To paste the example URL to your Excel workbook or Word document, just right click on it and copy the link address, then paste as needed.

  • Batch See the BatchSubmissionTool that will allow you to submit an Excel workbook to perform the VisualContour analysis in batch mode. The result of the batch processing is a list of URLs to GoogleMaps/GoogleEarth KML files that can be loaded in most web browers to display the service and interference contour areas. The FCC has a handy color picking tool ( surprise ) that can be used to select a hexadecimal number to represent the color of your contour(s) when using the VisualBatch tool.

    The one powerful feature of using batch processing for VisualContour is that you receive results/indications when an interference contour overlaps a service contour -- "visual inspection" of the contours is not necessary to determine "success" or "failure."

  • Be careful, some of the FCC rules contain language like 47 CFR 90.187 (b)(iii)(C)(iv) "The calculation of service and interference contours referenced in subparagraph (B) of this section and the determination of adjacent channel protection shall be done using generally accepted engineering practices and standards which, for purposes of this section, shall be the practices and standards agreed to by written agreement of all certified frequency coordinators."

    Ok..., where are the practices and standards agreed to ( by written agreement ) of ALL certified frequency coordinators? What/where are the "generally accepted engineering practices" cited in this example excerpt? Perhaps it is something like this: WP Docket 07-100, but it's not ( yet ) embodied in the 90.187 rule.

    A Word About the LMCC Adjacent Channel Contour Values (“ACCV”) - 150-512 MHz:

    In June of 2011 the LMCC requested that the FCC modify rules in 47 CFR 90.187 to accommodate their "ACCV" table. It appears that the LMCC got this: Amendment(s) published April 3, 2015, in 80 FR 18146. The VisualContour tool does not currently anticipate the LMCC "ACCV" table ( it does not appear to be “official,” yet ) – if there are any users out there that desire to have this feature, let us know and we will pursue adding it.

    Many contour rules rely on the "Carey Curves" as documented by the FCC reports R-6602, and R-6406; they are presented numerically in the FCC/OEC report RS76-01, and a great general interpretation of how to use the curves is discussed in the Wireless Innovation Forum's Geographic Contour Calculation Guidelines.

    Yes, the "66" in "R-6602" means 1966, the year the report was issued. In fact, not everyone is content with the current FCC rules that specify ( implicitly or explicitly ) the use of "contours" -- in that they rely on 40+ year old methods and assume we don't have access accurate geo-spacial data and/or the computational resources to do otherwise.



    VisualTerrainProfile

    The VisualTerrainProfile tool allows you to double-click on two distinct locations and it will display the path profile and the first Fresnel Zone along the path.

    This tool will only allow you to compute the terrain profile for two points that are < 113 km apart. If you specify two points that are >= 113 km apart, the map will reset (clear) and you will see a red diagnostic message near the bottom of the screen.

    If your two points are < 113 km, you should be able to zoom-in, double click for the first point, zoom out (use the mouse wheel), pan to the second point, zoom in (use the mouse wheel), and double click again to specify the second point – then the path profile will be displayed. The path profile will be drawn in blue and the first Fresnel zone will be drawn in yellow.

    If you wave the mouse over the markers, the latitude and longitude will be displayed for the respective point. The distance, in kilometers, between the two points is displayed on the horizontal axis of the path profile.

    You will need to provide the antenna height (meters) for the transmitter and receiver as well as the frequency (MHz) that will be used on the path. The current defaults are TxAntennaHeightMeters 40m, RxAntennaHeightMeters 2m, and FrequencyOnPathMHz 160 MHz. The reason Tx/Rx antenna heights, as well as TxFrequency, are necessary is so that the 1st in-phase Fresnel zone can be calculated using the equations as specified here.

    If your two points are > 113 km apart, you could consider using Google Earth tools such as Elevation Profie. There is a Fresnel Zone Java applet which is useful of you have no obstructions in your path (requires Java support in your browser).

    Why 113 km? – that’s related to FCC 47 CFR [FCC] 90.621 which states that protection from harmful interference is not guaranteed for stations that are 113 km, or greater, apart.



    VisualRadiusSearch

    VisualRadiusSearch is just a VisualSpectrumFinder query with the same beginning and ending frequency.



    VisualSpectrumFinder

    The VisualSpectrumFinder tool allows you to search for available spectrum at a given location ( latitude/longitude ). Different frequency bands have different requirements for their use. For example VHF and UHF bands have specific allocations for public safety and commercial entities. Channel spacing in VHF/UHF must comply with the FCC Narrowbanding rules where as public safety ( NPSPAC ) does not. This tool will allow you to search for frequency occupancy from 25 MHz up to 1000 MHz, and provide channel specific information in the following bands:

  • [ 025.0000 .. 030.0000 ] MHz [ VHF LO ]
  • [ 030.0000 .. 050.0000 ] MHz [ VHF LO ]
  • [ 071.0000 .. 076.0000 ] MHz [ VHF LO ]
  • [ 150.0000 .. 174.0000 ] MHz [ VHF HI ]
  • [ 220.0000 .. 222.0000 ] MHz [ VHF HI ]
  • [ 450.0000 .. 470.0000 ] MHz [ UHF LO ]
  • [ 470.0000 .. 512.0000 ] MHz [ UHF T ]
  • [ 700.0000 .. 806.0000 ] MHz [ UHF HI ]
  • [ 806.0000 .. 862.0000 ] MHz [ UHF HI ]
  • [ 869.0000 .. 901.0000 ] MHz [ UHF HI ]
  • [ 935.0000 .. 940.0000 ] MHz [ UHF HI ]
  • Notes:

  • For a given center frequency, there may be obvious co-channel conflicts. Adjacent channel conflicts are not as straight forward as the emissions mask ( e.g,. 20K0F3E ) may consume enough bandwidth to render a channel understudy as unusable.
  • Why does this tool as for a "proposed" AntennaHeightMeters and ErpWatts? These parameters are necessary to conduct a VisualContour study when you ckick through any of the links provided in tree-view mode.
  • Mobile channels that are paired with fixed channels are not analyzed. If the fixed channel in a pair is available/encumbered the mobile dual can also be considered available/encumbered.
  • Those searching for a narrowband channel may be impeded by incumbents that have yet to complete narrowbanding and the appropriate ULS licensing to reflect such. In this case, the SpectumFinder will alert you that someone, operating out-of-compliance ( as of 1/1/2013 ), with a wideband channel may be in your way -- you should be able to petition your coordinator and/or the FCC to provide relief or a remedy. Do note that the FCC has granted several waivers that allow licensees to continue to operate wideband equipment -- see FCC Guidance for Narrowbanding.
  • Visit NarrowBanding Tools at the OEC/ICTAP ( DHS ) to see how narrowbanding is progressing in your locale.
  • The Narrowband Summary Tracker is a tool that allows users to see summary information of how well states and counties are progressing in their efforts to narrowband from a licensing perspective.
  • The VisualSpectrumFinder allows an authenticated user to enter a frequency range, channel spacing, band-plan, and a center-point location latitude/longitude and search the FCC ULS License database for encumbrances up to 250 km from the specified center-point location.

    A list of zero or more encumbrances will be displayed. Expanding the list will enumerate details about specific encumbrances for a given frequency WRT the selected band-plan or channel spacing interval selected.

    The ViusalSpectrumFinder tool can be used in two (2) modes:

  • User Interactive where you fill in the required parameters and submit your study.
  • URL Argument where you specify the required parameters in a URL. This allows users to pre-stage and record their inquires using well-known applications such as Microsoft Excel or Word and get deterministic reproducible results by just clicking on a link. If you maintain your links in an Excel spreadsheet, you can copy/paste the results to the same spreadsheet.

    For example, do a Shift-Left-Click on this example URL. To paste the example URL to your Excel workbook or Word document, just right click on it and copy the link address, then paste as needed.

  • Finding available spectrum is not a perfect process. It assumes that:

  • The FCC ULS database correctly reflects what a licensee self-reports about their operations; occasionally the FCC get’s this wrong by not validating the data submitted or processes submitted paper forms incorrectly ( typos ). Sometimes licenses are granted to entities that are not entitled ( by FCC rule making ) to operate on specific frequencies, with specific emissions, at specific power or at specific locations. For example, sometimes the FCC assumes that if a license application endured frequency coordination that all is well and will grant the license carte blanche -- however, sometimes the frequency coordinators get it wrong.
  • The licensee self-reports the correct licensing information about their operations; the reality is that few licenses are 100% completely accurate as purveyed by the FCC’s ULS. (1) Often latitude/longitudes, elevations, antenna heights, ERP are not correct; (2) contact names/emails are stale; (3) many public safety organizations program their equipment with a neighboring jurisdiction’s channels for interoperability, yet they do not reflect this on any of their licenses; (4) equipment has changed and emissions and/or output power are different that what is reflected on the license; the list goes on…
  • All in all, the ULS licensing data is quite useable ( there really is no alternative ), but one must remain vigilant.

    One might think that finding an available frequency (F1) for a fixed location (L1) is a simple matter of determining if the closest entity, operating on frequency (F1) at location (L2), is far enough away so as to not interfere with operations around L1 – vice-versa for L2. Certain FCC rules dictate that the distance D between L1 and L2 be greater than a prescribed minimum ( e.g, 88 km for 800 MHz operation ( FCC 90.621 ) ). Certain FCC rules dictate that if the distance D between L1 and L2 is greater than a prescribed maximum ( e.g, 113km ) then there is no concern for deducing interference potential.

    And, it gets more complicated… One must also consider the impact of “adjacent” ( a.k.a., “offset” or “splinter” ) channels operating near L1. This is particularly true with band-plans that have adopted narrowbanding where channel centers are now at 6.25 and 12.5 kHz and have abandoned 25.0 kHz channel centers. 150 MHz, 450 MHz and 700 MHz band plans have done exactly that.

    For example, it is possible that a licensee ( operating in the 150-174 MHz VHF band ) has not yet meet the 1/1/2013 FCC deadline for narrowbanding compliance. They are operating on a standard channel, but using 20 kHz emissions ( e.g., emission code 20K0F3E ), and thus are illegitimately bleeding over to the next standard channel that would otherwise be unencumbered if they had met the mandated requirements of narrowbanding ( e.g., emission code 6K0F3E ).

    So, to get it right – and find an available frequency (F1) for use at (L1) – one must determine the emission band which F1 desires to use (e.g., 6.25 kHz ) and see if it overlaps any of the emission bands ( for the closest location L2 ) of either (1) the co-channel operation and/or (2) the adjacent-channel operation and/or (3) the juxtaposed-standard-channel operation whose distance D between L1 and L2 is material.

    To visualize these scenarios see the figure below:

  • Frequencies F02, F04, F06, F08, … are standard channels ( green ).
  • Frequencies F01, F03, F05, F07, … are adjacent/offset/splinter channels ( red ).
  • Frequencies F04, F08, F12, F16, … are both standard narrowbanding channels as well as legacy wideband channels ( dark blue ).
  • Standard channel Center frequency F04 has 20.0 kHz of deviation and possibly precludes the use of F02, F03, F05, and F06. Note that in a proper narrowbanding scenario, F04 should not preclude the use of either F02 or F06. But this stuff is still out there and one must test for this syndrome. Especially since the FCC Enforcement Bureau has no teeth when it comes to threatening a Public Safety entity with a rules violation. See the narrowbanding progress tool.
  • Standard channel F10 possibly precludes the use of the adjacent channels F09 and F11.
  • Adjacent channel F15 has 12.5 kHz of deviation and possibly precludes the use of F14 and F16.
  • The FCC does provide a means by which the required minimum distance between two locations L1 and L2 can be disregarded ( by waiver grant ), but this usually requires engineering studies that are acceptable to all parties involved ( the newly proposed operator, all existing incumbent operators, and possibly a frequency coordinator ). Such engineering studies typically involve 2D/3D field strength simulations ( e.g., service and interference contour studies ) and propagation analysis using sophisticated terrain databases and irregular shape models ( e.g., building geometries ). This is typically accomplished using pricey commercial software packages available on a unlimited-usage and/or usage-sensitive cost basis.

    The funny thing about these commercial software packages is that they usually produce comparable results, but sometimes they do not. There is no validation suite or test-bed that can be used to insure compliance to standards or rules to which they the purport to subscribe and implement/study algorithmically ( e.g., TSB-88C, FCC 90.621, R-6602 "Carey Curves," et al. ). C’est la vie.

    A Word About Planning Near is US Border: If you are looking for frequency assets near the Canadian or Mexican borders, there are specific rules that govern frequency, emission mask, power, antenna height, etc. On some areas along the border, sharing zone agreements sometimes favor Canada or Mexico over the US ( vise-versa ) depending on the current population densities in the area.

    First you should determine if you are looking for a transmitter location in the border sharing zone, and should you fall inside the sharing zone, you will need to consult specific rules that are germane to:

  • Canada
  • Mexico
  • 700 MHz Canada
  • 700 MHz Mexico
  • 800 MHz Canada
  • 800 MHz Mexico
  • when planning to use spectrum. This may require special coordination efforts with Canada or Mexico depending on your circumstances. It is not realistic for SpectrumFinder tool to anticipate all the nuances in sharing zone rules for Canada and Mexico -- so be careful on the border.

    See also: A primer in securing land-mobile spectrum The Long and Winding Road by Mark E. Crosby ( Enterprise Wireless Alliance ). This article treats many pragmatic issues for those that are building out a land-mobile infrastructure.

    A Word About Radio Telescopes: Designated "Quiet Zones" where entities are operating radio telescopes should be considered -- there may be local restrictions in operating in certain frequency bands near a radio telescope. See the GooleMaps tool that visually displays World Radio Telescopes And Radio Quiet Zones. Most links on the map will direct you to a website that usually describes specific local restrictions, if any.

    See also the option “Display FCC Designated QuietZones” in the ViusalMaximumErpWatts tool – it will graphically map and label the quiet zones designated by the FCC rules.

    FCC rules regarding "Quiet Zones" are specified in 47 CFR 1.924 ( Protected Radio Telescopes ) and 47 CFR 0.121 ( Protected FCC Field Offices ). Frankly there are probably other US Government "Quiet Zones" operated by you-konw-who whose monitoring location(s) are not published.

    A Word About Market (EA) Licenses: The commercial and private land mobile licenses specify site-specific transmitter locations, i.e., a latitude/longitude is specified along with the explicit transmitting frequency, power, antenna height, etc. Market licenses specify one or more ( block ) frequencies for a specific market area ( a geographic region defined by the FCC ). Market licenses do not specify the locations ( latitude(s)/longitude(s) ) of transmitters -- just the area in which they operate. FCC Market Areas enumerate geographic regions such as EAs ( Economic Areas ).

    What does this mean for the VisualSpectrumFinder tool? The tool does not attempt to resolve any spectrum encumbrances from Market licenses. So, although Market licenses primarily affect 220, 700 and 800 MHz LMR spectrum, you should always check for Market licenses at or near your proposed transmitter location using the FCC's Market Based License Search tool. The VisualSpectrumFinder will attempt to advise if a frequency is designated for market (EA/ESMR/SMR) allocations -- if the band-plan option is selected. So, during a spectrum finder operation, if you find free spectrum that is tagged (EA/ESMR/SMR) and desire to investigate if it is useable, then use the FCC's Site/Market Based License Search tool to confirm that it is not encumbered in your market area by a market licensee.

    Market License Radio Service Codes:

  • AD - AWS-4
  • AH - AWS-H Block (1915-1920 MHz and 1995-2000 MHz)
  • AW - AWS, 1710-1755/2110-2155 MHz bands
  • BA - 1390-1392 MHz Band, Market Area
  • BB - 1392-1395 and 1432-1435 MHz Bands, Market Area
  • BC - 1670-1675 MHz Band, Market Area
  • BR - Broadband Radio Servicev
  • CJ - Commercial Aviation Air-Ground Radiotelephone (800 MHz band)
  • CL - Cellular
  • CN - PCS Narrowband
  • CP - Part 22 VHF/UHF Paging (excluding 931MHz)
  • CW - PCS Broadband
  • CY - 1910-1915/1990-1995 MHz Bands, Market Area
  • CZ - Part 22 931 MHZ Paging
  • DV - Multichannel Video Distribution AND Data Service
  • ED - Educational Broadband Service
  • GC - 929-931 MHz Band, Auctioned
  • LD - Local Multipoint Distribution Service
  • LS - Location and Monitoring Service, Multilateration (LMS)
  • MS - Multiple Address Service, Auctioned
  • PC - Public Coast Stations, Auctioned
  • QA - 220-222 MHz Band, Auctioned
  • TC - MSS Ancillary Terrestrial Component (ATC) Leasing
  • TN - 39 Ghz, Auctioned
  • TZ - 24 GHz Service
  • WP - 700 MHz Upper Band (Block D)
  • WS - Wireless Communications Service
  • WU - 700 MHz Upper Band (Block C)
  • WX - 700 MHz Guard Band
  • WY - 700 MHz Lower Band (Blocks A, B & E)
  • WZ - 700 MHz Lower Band (Blocks C, D)
  • YC - SMR, 806-821/851-866 MHz, Auctioned
  • YD - SMR, 896-901/935-940 MHz, Auctioned
  • YH - SMR, 806-821/851-866 MHz, Auctioned (Rebanded YC license)
  • ZV - 218-219 MHz Service
  • A Word About 800 MHz Spectrum Vacated by Sprint/Nextel ( 854-860 MHz ): After the 800 MHz TA (Transition Administrator) certifies that a NPSPAC PS (Public Safety) Region has completed re-banding, spectrum vacated by Sprint/Nextel is then made eligible for licensing exclusively to PS entities for the first three (3) years after the release of the frequencies. After that, it would be exclusively available to PS and CII eligible entities for the following two (2) years. After the five (3+2) year PS/CII period, the spectrum would then open up to any eligible applicant. See: FCC DA 08-2464 and FCC DA-14-1904A1.

    What does this mean for the VisualSpectrumFinder tool? You may see spectrum available in the 854-860 band that is actually “encumbered” by the FCC’s Vacated Spectrum shell game. So, you may want to use the FCC VCSE tool to check the 854-860 MHz frequencies interleaved band. Why do we elude to a “shell game?”

  • NPSPAC PS regions of lower density ( e.g., Alaska, Nebraska, North Dakota ) will typically clear before higher density PS regions, see this ( FCC web document )
  • Lower density PS regions can border high density PS regions not yet “clear.”
  • CII entities can secure spectrum on borders in low density regions which effectively encumbers spectrum in a neighboring high density PS region not yet deemed clear ( i.e., where the three (3) year clock has not even started for PS entities ).
  • And watch for the same syndrome in the Expansion Band (EB, 860-861 MHz) and Guard Band (861-862 MHz) where there is a land-grab in progress. Look at the license activity for ( RapidLink Wireless, LLC; 800 Frequency Group LLC; Bluegold Spectrum, LLC; Spectrum Acquisitions Group, LLC; Vertical Ventures II, LLC; et al. )
  • The FCC (PSHSB/WTB) has established an 800 MHz Vacated Channel Search Engine enabling PS and CII entities, frequency coordinators, and the public to identify 800 MHz channels in the Interleaved Band (809-815/854-860 MHz) that have been relinquished by Sprint/Nextel as part of re-banding. Spectrum can appear as a fixed frequency-location asset, or a market based asset – it’s complicated.

    A Word About 800 MHz ( 854-862 MHz ) Interstitial/Offset Assignments: In October of 2009 the EWA (Enterprise Wireless Alliance) petitioned the FCC for spectrum relief in the 854-862 MHz band where the creation of Interstitial 12.5 kHz Channels was requested. In February 2015 ( 5+ years later ) the FCC responded with an NPRM to accommodate the request.

    The good news is that the VisualSpectrumFinder anticipates this with its existing 800 MHz band plan. Should the rule making utilize the contour methods proposed in the NPRM, we will adjust our VisualContour tool to accommodate them. The jury is still out on this rule making – stay tuned.

    A Word About the LMCC Adjacent Channel Contour Values (“ACCV”) - 150-512 MHz:

    In June of 2011 the LMCC requested that the FCC modify rules in 47 CFR 90.187 to accommodate their "ACCV" table. It appears that the LMCC got this: Amendment(s) published April 3, 2015, in 80 FR 18146. The VisualContour tool does not currently anticipate the LMCC "ACCV" table ( it does not appear to be “official,” yet ) – if there are any users out there that desire to have this feature, let us know and we will pursue adding it.

    A Word About Frequency Coordination: In many metropolitan areas the finite supply of spectrum resources ( frequencies ) are in very high demand. Part of the frequency coordinator’s job is to see that the “most deserving” entity be allocated these scarce resources as they become available. As you might imagine, there will be some horse-trading and politics involved – so finding a “open” frequency using this tool does not guarantee that you will be allowed to use it – as it may already have been spoken for by those waiting in line under coordination. On the flip side, some frequency coordinators are not as meticulous as others and may be unaware of free spectrum – so the bottom line is: Know what’s available, and politely ask for it.

    Known frequency coordinators ( per the FCC ) are:

  • [AAA] AAA Frequency Coordination c/o RadioSoft, Inc.
  • [AASHTO] American Association of State Highway and Transportation Officials
  • [APCO] Associated Public Safety Com Officrs Inc.
  • [AAR] Association of American Railroads
  • [CSAA] Central Station Alarm Association
  • [EWA] Enterprise Wireless Alliance
  • [FIT] Forest Industries Telecommunications
  • [FCCA] Forestry Conservation Communications Association
  • [IMSA] International Municipal Signal Association (IMSA)
  • [MRFAC] Manufacturers Radio Freq Adv Comm Inc.
  • [WIA] Wireless Infrastructure Association (formerly PCIA)
  • [UTC] Utilities Telecom Council
  • [OTHER] Coordinator
  • The WIA has a good set of answers to common FAQs on frequency coordination.

    The Enterprise Wireless Alliance (EWA) has an iPhone/Android mobile app CEVO that purports to assist in finding spectrum for BILT and Public Safety entities. We've used the Android CEVO app [10/12/2014], and tested it to find spectrum in the 800 MHz band; it identified candidate frequencies "for coordination" that were clearly encumbered by existing licensees ( < 88km / FCC 90.621 ) -- so we're not too sure how useful this tool really is. It appears to be relatively simple, not too visual, and more of a marketing tool to have you engage the paid services of the EWA to coordinate your license. The EWA has released a web based Cevo Toolbox [2015.09.22] and it appears pretty thin in LMR engineering functionality. It's missing the ability to produce service/interference contours, analyze DHAAT/ShortSpacing (FCC 90.621), and the tool that purports to find "candidate" frequencies does not appear to work very well ( it identifies clearly encumbered frequencies as "candidates" ). It’s certainly not a very visual tool.



    VisualCoverage

    It appears that GoogleMaps has decided to drop support for KML file imports -- this non-sense started sometime in February 2015 -- if you use this VisualCoverage feature, you will need to become familiar with Google's My Maps and explicitly import the KML file produced by the VisualCoverage tool. Better yet, install the GoogleEarth application and utilize its powerful features such as layer control and hierarchical overlay organization.

    "From February 2015, maps created in the classic Google Maps — https://maps.google.com/ — will no longer load KML/KMZ files from external websites. However, we know that KML files are a really useful way to work with geographic data, so we’ve added KML to Google My Maps, and continue to support this format with other Google Maps APIs. We hope that one of these options will meet your needs." -- GoogleMaps

    The VisualCoverage tool allows you to plot a 2D/3D signal coverage overlay on a GoogleMap showing terrain or satellite ground views.

    Once this study completes processing, you will be presented with five URL/links that can be used to display the:

  • Signal coverage area in 2D (GoogleMaps)
  • Signal coverage area in 3D (GoogleEarth)
  • GoogleMap/GoogleEarth KML overlay file
  • Signal overlay file
  • Power legend overlay file
  • These links, and the content to which they point, persist -- so you can email them to your colleagues for review and/or save them in a word or spreadsheet document for later use.

    To utilize the 3D GoogleEarth URL you must install the GoogleEarth application and/or GoogleEarth browser plug-in. The 3D GoogleEarth display will now correctly display the optional service/interference contours, if selected. If the 3D GoogleEarth plug-in does not appear to work in your browser, do check for alert icons/pop-ups that might suggest that it is currently blocked by your browser's settings. If blocked, configure your browser to allow them. Google documentation hints that the classic GoogleEarth plug-in support for Windows XP users will be deprecated.

    Once GoogleEarth starts, the Shift and Ctrl keys can be used, in conjunction with the mouse-wheel or up/down arrows, to perform zoom functions on the pitch and yaw axes, respectively.

    Should you desire a rich 3D display of your coverage area, start the GoogleEarth application, download the file pointed to by the Google Earth KML URL, click/navigate File -> Open and paste the KML URL and go. You will be able to selectively enable/disable multiple display layers such as roads, traffic, as well as the VisualCoverage layers.

    Or, on the Google Earth tool bar, select Add -> Network Link and paste the KML URL in the Link: text box and click OK.

    If you have a percistent VisualCoverage URL pointing to a .KML coverage file, you can use this URL in the GoogleMap "My Places" menu.

    What VisualCoverage will do:

  • Display valid coverage maps inside the regions enumerated by this SRTM Survey Map
  • Present a relative view of signal strength coverage – it should show the effects/implications of the surrounding terrain and how a signal degrades on a propagation path.
  • Present signal coverage with the assumption that the antenna pattern is omni-directional, which is usually the case for “high-site” LMR operations. It assumes that you know the true ERP ( Watts ) at the antenna, so you must consider transmitter power, line-loss, insertion-loss, antenna gain, etc.
  • Provides a set of URLs that can be utilized by GoogleMaps(2D)/GoogleEarth(3D) to view a coverage area. These URLs can be emailed or copied to a spreadsheet for later use.

    Those utilizing the GoogleEarth application (not plug-in) can import the KML files that contain the results of your VisualContour study by issuing the GoogleEarth command File->Open and paste the URL into the combo-box File name. It's really that simple! GoogleEarth will let you organize your studies in different folders and save your URLs between sessions.

  • Optionally display a matrix/tile coverage map where you specify the signal strength (dbμVm) and a tile color. The map will show all the geography that has your predicted signal strength. You may specify one or two different colors and for their respective signal strengths.

    When selecting colors be mindful of the respective power level. If a color ( A and/or B ) is left unselected, its respective power level still participates in the rendering of the coverage – it’s geographic area will be transparent. To negate the participation of a signal strength profile ( A and/or B ) set it’s power level to zero (0) no matter what color is selected.

  • Optionally provide service and interference contours so that they may be compared to the actual predicted coverage.
  • See a 3D GoogleEarth demo on YouTube: Mt. Baker and Chicago Fly-Over.

    What VisualCoverage won't do:

    • Display valid coverage maps outside the regions enumerated by this SRTM Survey Map
    • Allow you to anticipate antenna patterns other than omni-directional -- the staple for LMR high-site operations.
    • Allow you to specify real-world obstructions, but it will let you approximate the average ground clutter on the terrain.
    • Allow you to specify more than one transmitter for a study.
    • Guarantee the accuracy of the signal strength at any location – there are just too many parametrics involved:
      • The accuracy of the NASA SRTM ( Elevation ) dataset
      • Omitting the incorporation of real-world "shadow" obstructions like buildings, towers, water tanks, et. al, even if they are shown in the GoogleEarth landscape. It can be said, however, that the SRTM data does reflect heights of "large" obstructions, like a sports stadium, but not a flag pole.
      • Knowing the true ERP at your transmitting antenna
      • Knowing the true receiver threshold(s) as most radio networks have disparate receiver types -- you need to model with the least efficient receiver in your system.
      • Correctly matching the environmental parameters such as:
        • TerrainType
        • TerrainDielectricConstant
        • TerrainConductivity
        • ClimateType
        • GroundClutter

    The ViusalCoverage tool can be used in three (3) modes:

  • User Interactive where you fill in the required parameters and submit your study. It you desire to use GoogleEarth ( that's the cool part ), your computer should have a GPU, or a CPU with four (4) cores, for the best results.
  • URL Argument where you specify the required parameters in a URL. This allows users to pre-stage and record their inquires using well-known applications such as Microsoft Excel or Word and get deterministic reproducible results by just clicking on a link. If you maintain your links in an Excel spreadsheet, you can copy/paste the results to the same spreadsheet.

    For example, do a Shift-Left-Click on this example URL To paste the example URL to your Excel workbook or Word document, just right click on it and copy the link address, then paste as needed.

    Want to see a Matrix/Tile example where you can ask for a display for a specific signal strength ( dBuVm ) ? Try this demo.

  • Batch See the BatchSubmissionTool that will allow you to submit an Excel workbook to perform the VisualCoverage analysis in batch mode. You may submit up to ten (10) VisualCoverage studies in any one batch submission. The result of the batch processing is a list of URLs to GoogleMaps/GoogleEarth KML files that can be loaded in most web browers to display the coverage area. Three-D viewing is available with GoogleEarth.
  • The VisualCoverage tool currently utilizes an open source derivative of the SPLAT! Tool with credit largely going to John A. Magliacane (KD2BD). The SPLAT! Tool has since been ported by Alex Farrant to a server oriented implementation. The VisualCoverage tool puts a porting wrapper on these codes ( there were no algorithmic/logic changes made ), and they are available here: SplatNativeWin32Console.cpp and itm.cpp and conform to the GPL.

    An industrial strength derivative of the SPLAT! tool is offered by CloudRF -- this tool appears to have all the bells and whistles -- it operates on multiple platforms, it allows for the specification of antenna patterns, grid resolution, and obstructions, it can deal with multiple transmitters, it works outside the CONUS, etc. You will, however, need to register with them and pull out your credit/debit card.

    The SPLAT! framework finds its origins in the NTIA's Longley-Rice ITM FORTRAN and C++ codes. Frankly, the FORTRAN and C++ codes provided by the NTIA are a little messy, so it's best to review the some of the ITM Pseudo-Code and ITM Algorithms. The NTIA C++ port is appears to just a translation of the original FORTRAN code developed in the late 1960's -- the power of C++ ( object oriented, polymorphic, hierarchical etc. ) is clearly not utilized, but hell, it's a FORTRAN port ( you can write FORTRAN in almost any language ).

    The underlying terrain model that is used by VisualCoverage to deduce signal strength relies on the accuracy/performance of the ITM/ITWOM model(s). See Shamate, et. al. comments for a broad review of these models. See also A Comparision of the ITM and ITWOM Models. See also the originnal NTIS Longley/Rice report Prediction of Tropospheric Radio Transmission Loss Over Irregular Terrain - A Computer Method (1968).

    The only way to verify the accuracy of anyone's coverage prediction is to do a “drive-test” – plain and simple. You will need a transmitting beacon, know the true ERP at the transmitter's antenna, the gain of the receiving antenna and a way to measure the field strength with a trusted calibrated instrument. This is not a trivial task and involves a lot of detailed work, if done properly. The complexity of "drive testing" was presented at a 2007 IWCE conference by Jacobsmeyer and Weimer. See also a paper by Jacobsmeyer and Trott.

    Forthcoming is a port and parallel decomposition of the NTIA ITM/SPLAT! C++ code using the OpenMP framework that allows an application to utilize multiple CPU cores. This can afford performance gains up to six (6) fold on a ordinary multi-core processor -- work done by Andre Montenegro Ferreira demonstrates this. Also forthcoming is a port and parallel decomposition of the NTIA ITM/SPLAT! C++ code using the OpenCL and AMP frameworks to utilize up to 1024 concurrent GPU cores and this shows great promise; this will allow coverage maps to be generated in near real-time! This type of parallelism work is currently addressed by: AMusselm, Song. and University of Arizona/ECE (p77)



    WebServices

    The VisualLmr tools use a backend web service to do Elevation/HAAT/DHAAT/ShortSpacing/ContourAnalysis/TerrainProfile/SpectrumFinding processing to present the results you see.

    This web service is available for those that have authentication credentials ( userName, userPassword, userDomain ). The web service is suitable for those entities that desire to programmaticaly process an analysis vs. manual one-at-a-time requests from a VisualTool web page. This web service is suitable for those developing applications that desire to obtain information programmatically, or on-the-fly, for interactive client or server applications.

    ExternalWebService for programmers that would like to use a M2M ( Machine-2-Machine ) interface. The WSDL for the ExternalWebService describes available facilities.

    SOAP/WSDL/UDDI

    If you are a C++ ( example ), C# ( example ), VisualBasic ( example ) .Net developer or a Java developer using tools that support SOAP on IBM, MONO (Linux), or Axis/Java platforms you are in luck. You can utilize the engine that drives the VisualLMR tools.

    Before getting wound up using the WebServices interface, make sure that you understand that it is intended facilitate M2M ( Machine-2-Machine ) or A2M ( Application-2-Machine ) automations. Esentially you bake this interface in to a clint or server application, and it is "headless" ( i.e., it has no grapic user interface ).

    Consider using the BatchSubmission Tools as if you desire to work with the VisualLmr tools interactivly.

    If you desire to utilize the web services interface, and you are a non-profit ( e.g., public safety, education, humanitarian, etc. ) contact us and we'll get you fixed up, gratis.



    REST

    REST is not supported, although the VisualShortSpacing, VisualContour, VisualCoverage and VisualSpectrumFinder tools can be driven from parameters in their respective URLs ( much like REST ).

    For the particular web services that are offered here, a formal REST implementation was just not expressive enough to offer these services in an efficient and useful way. REST lacks many abilities/features for self-discovery (UDDI/WSDL), complex data types, exception handling, and error recovery facilities that are useful and powerful for the type of web services that are offered here.

    The RESTful framework is arguably much more suitable than the SOAP/WSDL/UDDI framework for the majority applications that are simple in nature. The web services offered here at VisualLMR are not simple in nature.

    Microsoft/MSDN: More On REST




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