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Wireless Mic/LPAS

Wireless Microphones and Low Power Auxilary Service Devices (LPAS)

Guidance on Channels for Wireless Microphones and Other Low Power Auxiliary Service (LPAS) Devices

  1. Channels to be reserved for wireless mics and other LPAS devices ("Reserved Channels")

    • This guidance provides clarification regarding the identification of channels that are to be reserved for use by wireless microphones and other LPAS Devices (jointly "wireless microphones") at a specified location. (Note: these channels will not be made available for TVBDs)
    • Up to two TV channels, where available, are to be reserved for use by wireless microphones at all locations. These reserved channels are taken from the pool of all TV channels (2-51) available for white space devices (TVBDs). The reserved channels definedas the first channel above and the first channel below channel 37 (or the two closest channels on one side of channel 37 if no other channels are available) that are not occupied by an authorized service protected under the white space rules or that are otherwise precluded from white space use (geographic preclusion area, etc.). In determining the reserved channels, TVWS database administrators are to consider white space channels where wireless microphones have registered for protection per Section 15.712(f) as available (i.e. such channels, assuming they meet the criteria specified above, should be designated as the reserved channels).
    • Availability of channels for TVBDs should be interpreted as broadly as possible; all types of TVBD operation should be considered – from 40 mW personal/portable (P/P) to fixed devices with a high (or low) antenna. For example, only fixed TVBDs are allowed on channels 20 and below. Above channel 20, P/P devices are allowed to operate on channels adjacent to TV stations within the station’s service area at 40 mW. The ability of any type of TVBD to operate on a channel means the channel is available for use by TVBDs and by extension available as a candidate for a wireless microphone reserved channel.
  2. Availability of Certain Channels for Wireless Mics and Other Low Power Auxiliary Service (LPAS) Devices ("Other Available Channel)
    • This guidance provides clarification regarding the identification of channels that are available for use by wireless microphones and other LPAS Devices (jointly "wireless microphones”) and not white space devices at a specified location. Note first that the channels available for wireless microphone use are different in some respects from channels available for white space devices. Under the rules, channels used by the four services listed below are not available for use by white space devices, but are available for wireless microphone use:
      • MVPD and TV translator/lower power TV station receive sites;
      • The receive sites of BAS licensed and temporary BAS facilities;
      • Radio astronomy sites and;
      • Offshore radio telecommunications services.
    • Therefore, when determining available channels for wireless microphones, the databases should include these channels in the "other available channels” list. The reason that wireless microphones are not excluded from channels used by the above four services/operations is that, while wireless microphones are allowed to operate on a non-interference basis (see 47 C.F.R. § 2.106 NG115) and selection of their frequencies is to be guided by the need to avoid interference (see 47 C.F.R. 74.861(g)), the wireless microphone rules do not specify specific interference protection criteria.
    • When determining the channels that are available for use by wireless microphones, the TV whitespace databases should exclude from availability channels that are used by any class of broadcast television station (full power, Class A, low power TV and TV translator) and both metropolitan reserved and waivered UHF land mobile operations (see protection requirements below). With regard to protection of TV and UHF land mobile services, the rules (Section 74.803(b)) provide that low power auxiliary devices/wireless microphones are secondary to TV broadcasting and land mobile stations operating in the UHF bands and must not cause harmful interference to them. The rules do not, however, include specific standards or other criteria for protection of those services from interference from wireless microphones. The great majority of wireless microphones operate with power and antenna gain similar to 40 mW personal/portable (P/P) TV bands devices (TVBDs) and the provisions for protection of TV and land mobile operations from TVDBs could also be expected to adequately protect those services from wireless microphones. To avoid the possibility of interference to TV and UHF band land mobile services by wireless microphones, the TVWS databases therefore should not identify a channel as available for wireless microphone use at locations where that channel is not allowed to be used by 40 mW P/P TVDBs or fixed TVBDs with antenna height less than 3 meters on a co-channel or adjacent channel basis in accordance with Sections 15.712(a)(2) and (d) of the rules. Using these standards for determining wireless microphone availability will protect TV service and UHF land mobile operations from wireless microphone operations within their respective service contours and ranges of operation.
  3. Registration of Wireless Mics on Reserved Channels and Channels Used by TV Stations and and T-Band Land Mobile Channels
    • Question-- Are wireless microphone registrations allowed to request protection on the two channels reserved for their use at any given location? Updated 5-6-13
      • Answer -- Wireless microphone registrations may request protection on the two reserved channels. As stated above, it is not necessary for wireless microphones to be registered for protection against interference from TVBDs on those channels. However, it does not cause any particular problem if wireless mics are registered for protection on the reserved channels. Again, in order to avoid confusion for the wireless mic users, the TVWS database systems may allow registrations to protect wireless mic operations on the two white space channels reserved for their use at each location (note that such registrations will not secure the registrant additional protection and thus are pro forma only). Thus, the TVWS database systems should allow wireless microphone users to register for protection on the two reserved channels.
    • Question -- Are non-white space channels that are co-channel and first-adjacent to TV broadcasting and T-Band land mobile services available for wireless microphone operation and if so, are wireless microphone users allowed to register for protection on those channels?
      • Answer -- The rules (Section 74.803(b)) provide that low power auxiliary service (LPAS) devices /wireless microphones are secondary to TV broadcasting and UHF land mobile stations operating in the UHF bands and must not cause harmful interference to them. They do not, however, include specific standards or other criteria for protection of those primary services from interference from wireless microphones. Notwithstanding this situation, guidance is needed on how to determine wireless microphone "other available” channels considering protection of TV and land mobile services. In addressing this issue, we observe that the great majority of wireless microphones operate with power and antenna gain similar to 40 mW personal/portable (P/P) TV bands devices (TVBDs) and that the provisions for protection of TV and land mobile operations from TV white space devices could also be expected to adequately protect those services from wireless microphones. 40 mW P/P TVBDs are not allowed to operate on channels that are co-channel to TV service or that are co-channel or first-adjacent to land mobile operations within the distances specified in Sections 15.712(a)(2) and (d) of the rules (in the case of wireless microphones, the 40 mW standards for P/P TVBDs can also be applied below channel 21). Therefore, for purposes of considering TV broadcasting and land mobile operations in identifying "other available” channels for use by wireless microphones, the TVWS databases should use the standards for protecting those operations from 40 mW P/P TVBDs. Specifically, if the location is within the distances to a TV broadcast service contour or land mobile protected area where a 40 mW P/P TVBD would not be allowed to operate, the database should not show the channel as an "other available” channel for wireless microphone use.
    • Consistent with the above, the databases should not allow wireless microphone users to register for protection on channels used by those TV broadcasting and land mobile stations. Relatedly, the databases also should not allow wireless microphone users to register for protection on "other available” channels used by other services/operations. In this regard, wireless microphones are only allowed to register for protection on channels determined as available for white space use according to Section 15.712 of the rules, excluding subsection (f), i.e., channels registered for protection of wireless microphones and other LPADs.

Unlicensed Wireless Microphone Registrations & ULS Approval Expiration Dates

    • Question-- How the TVWS databases should treat registrations for protection of unlicensed wireless microphone (UWM) operations that are scheduled for time periods after the expiration date of the venues FCC approval to register in the ULS (these would be registrations entered before the expiration date for dates after that time)?

      • Answer -- Such registrations should not be protected. To apply this policy, the database administrators should not accept registrations for a date later than the expiration date of the venues ULS approval record.

        To avoid situations where a UWM venue’s registration privileges expire so that it is not allowed to make registrations and has to wait through the 30-day period for obtaining a new approval to register, you might consider advising the party responsible for a venue’s registration of the need to re-register in advance of its approval’s expiration date. For example, a database that accepts an original registration request (before synchronization) might notify the venue two months in advance of the expiration date of its approval to provide the registrant sufficient time to re-apply to obtain an extension of its approval. (If a venue entered registrations through two or more databases it would then receive renewal advisements from each database through which it had entered at least one registration.)
      • Question -- For the licensed wireless microphones, will you expect the database administrators to only allow operation on the frequency ranges specified in the corresponding license? Updated on 4/15/13
        I am asking because not all licenses specify the entire TV band.
        • Answer -- The database administrators are required to protect licensed wireless microphone operations on any channel specified by the licensee/registrant; the channels that may be specified are not limited to those listed on the license. However, the TV white space databases are not to allow registration for protection of LPAS operations on channels that are occupied by, or otherwise protected, for licensed services or on channels that are protected within specific geographic areas as set forth in the rules.
      • Question -- How do Database Administrators implement methods for specifying areas where licensed Low Power Auxiliary (LPAS) devices and unlicensed wireless microphones will be protected from TV whitespace devices?
        • Answer -- This is to provide information on the methods to be used for specifying the areas where licensed low power auxiliary (LPAS) devices (primarily wireless microphones) and unlicensed wireless microphones will be protected from TVWS devices.

          The rules (Sections 15.713(h)(8) and (9), 47 C.F.R. § 15.713(h)(8) and (9)) provide for specification of a geographic point (set of coordinates) around which protection for these devices will be provided out to 400 meters from personal/portable TVWS devices and out to 1 km from fixed TVWS devices. They also allow registration of more than one geographic point for very large sites.

          At TVWS Workshop 3, we recognized that the number of points specified for a registration could be relatively high in a few special cases and stated that we will allow specification of protection zones with boundaries defined by a series of points connected by straight lines (polygons) as an alternative to specification of multiple points. We also said we would allow registrants to specify circles based on a requested radius.

          We are now providing certain standards for the specification of protection zones for wireless microphones. First, from a practical standpoint in designing the registration components of the database systems, we find that there needs to be a limit on the number of points that can be specified. We believe that 25 points are adequate to define the area of a large venue where LPAS devices and/or unlicensed wireless microphones are used. This is a relatively large number of points and if a registrant needs to specify more, it can submit a second registration. Our registration system for unlicensed wireless microphones will allow a maximum of 25 geographic points; the database systems are also to use 25 as the maximum number of points that may be specified in their registration systems for LPAS and unlicensed wireless microphones.

          We emphasize that it is our intention that the identification of a single set of coordinates is to be the principal means for specifying the protection of LPAS and unlicensed wireless microphone operations from interference caused by TVWS devices. We expect that the vast majority of registered venues will be single building or an otherwise relatively contained site that will be adequately protected by specifying a single set of coordinates.

          We also continue to believe that providing an option to specify a geographic area based on a polygon is desirable to simplify the registration process for geographically very large venues that use wireless microphones. However, because the area of a circle can be roughly approximated by a square, we do not believe it is necessary to include a circle option as it would add complexity to the scheme and would not add significant benefit. The database systems should not provide for specification of circles in the protection of LPAS and unlicensed wireless microphones.

          Under the polygon option, protection of LPAS and unlicensed wireless microphones from personal/portable and fixed TVWS devices will be provided out to 400 meter and 1 km, respectively, from the edges of straight lines connecting the vertices (geographic points) of the polygon. To keep this option both simple and useful and to limit their size so as not to provide protection that is more than is typical of the area of most very large venues, such as an auto race track or a theme park, we are imposing the following limits:. Each polygon must be specified with four geographic points and limit the distance between any two adjacent points to 3 km. To provide for the very few instances where a venue and its use of wireless microphones may occupy a larger area, we will allow up to four polygons to be specified in a single registration request. However, we observe that very large protected zones will limit the availability of TVWS channels and are concerned that there is potential for abuse of this option by wireless microphone users seeking greater protection than that afforded by the single point specification. Therefore, in the case of requests for registration of venues where unlicensed wireless microphones are used, we will carefully examine requests for protection of large areas and especially for multiple polygons. We will reject requests or modify the protection provided in such cases if we find that the area where wireless microphones are used is limited to a significantly smaller area or to a location that could be adequately protected by a single point registration. In the case of licensed LPAS devices, we will periodically examine registrations where large areas are protected and, if it appears that the venue could be adequately protected by specification of a more limited area or a single point, may request that the registrant provide additional information as to the need for such protection and make adjustments to the registration as we may find appropriate.

Guidance for Registering LPAS Operations

    • Question -- How are TV white space databases to determine whether a party is eligible to register a site where licensed wireless microphones/low power auxiliary device are used? (updated 11/25/13)

      • Answer -- For licensed wireless microphones and other devices such as wireless video assist devices authorized in the low power auxiliary service (LPAS) under Section 74.832 of the rules, the call sign of the associated LPAS license should be used as a check for eligibility to register a site. The call signs of LPAS licenses are available in the Commission’s Universal Licensing System (ULS) database. The service codes of the LPAS licenses in that database are “LP” and “LV”. If the LPAS call sign indicated in the registration request is in the ULS and its status field is “Active,” the applicant is eligible to register the site. Note that records with status fields “Cancelled,” “Expired” or “Terminated” are to be ignored – no registration requests should be allowed for those records.

        In addition, Section 74.24 of the rules allows broadcasters to operate wireless microphones and other LPAS stations on a short term basis (not to exceed 720 hours annually per frequency) under the authority conveyed by their Part 73 (broadcast station) license without prior authorization by the Commission, and in particular without a separate LPAS ULS license. As such operations on a licensed basis (under the authority of the TV station license), they are also eligible to register such sites with TV white space databases using their Part 73 call sign.

        TV white space database systems should therefore accept the valid call sign of either a broadcast station license or a LPAS license as indication of eligibility to register a site where licensed wireless microphones are used.

        Also, in many cases the records for LPAS licenses in the ULS specify specific frequency bands for operation. Some of these records specify frequencies that are authorized for LPAS operation but are not in the TV bands. One might therefore conclude that LPAS licensees would only be allowed to register with the TV white space databases for protection on channels that correspond to the frequencies on their license. This is not correct, however, as the rules in fact allow any broadcast licensee to operate on any of the full range of LPAS frequencies. In this regard, Section 74.832(h) of the rules provides in relevant part that “Operation of low power auxiliary stations …. in other bands [than those specified on the license] is permitted without further authority of the Commission. However, operation of low power auxiliary stations shall, at all times, be in accordance with the requirements of Section 74.882 of this subpart.” (Section 74.882 provides in relevant part that operation of low power auxiliary stations is limited to the specific frequency bands listed in Section 74.802(a)) of the rules, some of which are not in the TV bands.) Thus, a broadcast licensee may operate an LPAS station at a given location on any frequency that an LPAS station is authorized to use at that location, regardless of the frequencies specified on its license. We also note that other LPAS eligibles may operate additional frequencies by simply requesting a modification to their license. To address these considerations and simplify the registration process for all LPAS eligibles, the TV white space databases therefore are to collaterally allow LPAS licensees to register for protection on any TV channel in the TV bands regardless of the frequency band specified on the license. However, the TV white space databases are not to allow registration for protection of LPAS operations on channels that are occupied by, or otherwise protected, for licensed services or on channels that are protected within specific geographic areas as set forth in the rules. We also note that the TV white space databases are not responsible for providing protection to LPAS operations outside of the TV bands

        The ULS database typically contains some LPAS licenses are marked as “Active” but have an expiration date that has passed. For various reasons, all LPAS licenses marked as Active are still valid even if their expiration data is passed. The TV white space database systems should therefore allow registrations of sites for LPAS licenses that are marked as Active, regardless of their expiration date.

      • Question -- 6. 15.707(a) clarification – are channels 36 and 38 ever available for TVBD use or are they always reserved for wireless mic use?
        • Answer -- These two channels will always be either used by a licensed service or reserved for wireless microphone use and therefore will never be available for TVWS operation.

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Broadcast Auxiliary Services

Broadcast Auxiliary Services

Validation of Temporary BAS Registrations

Validation of eligibility for registration of temporary BAS stations in the TVWS databases cannot rely on the information from the temporary BAS license because there are no records for temporary BAS stations in the ULS database. However, only broadcast licensees and BAS licensees are eligible to operate temporary BAS stations. Therefore, to validate temporary BAS registration eligibility the TVWS databases should check the call sign on registration requests to verify that the registrant is a broadcast station or BAS station licensee. Parties eligible for temporary BAS stations include licensees of broadcast stations, i.e., full power TV, Class A TV, low power TV, TV translator, FM radio and AM radio broadcast stations, and licensees of BAS stations.

In the CDBS, the service codes for licensed broadcast stations are: DT (full power DTV), DD (full power DTV operating DTS), CA (Class A analog TV), DC (Class A DTV), TX (TV translator or low power analog), LD (TV translator or low power DTV), FM (FM radio) and AM (AM radio).

In the ULS, the service codes for licensed BAS stations are: TB (TV booster), IT (TV intercity relay), TP (TV pick-up), TS (TV studio transmitter link), or TT (TV translator relay)).

There are no aural (radio) BAS stations in the TV bands, so there should not be any temporary BAS registration requests from licensees of stations with service codes AB (aural microwave booster), AI (aural intercity relay) or AS (aural studio transmitter link). Those codes should not be considered valid for temporary BAS registrations.

Guidance for Processing of Requests for Very Short Temporary BAS Links

It has been reported to OET that occasionally a party will request a registration for a temporary BAS link for which the distance between the transmitter and the receiver of the link is very short (on the order of a few meters or tens of meters) or, somewhat more frequently, the transmitter and receiver will be co-located (perhaps a data entry error). While not addressed in the rules, such registration requests are plainly not valid and therefore are not acceptable and should be rejected by the TVWS databases. A guideline is needed for determining whether the distance between the transmit and receive sites of a requested temporary BAS link is too short. We are therefore instructing the TVWS database administrators to reject requests for temporary BAS registration that would operate over distances of less than 100 meters. In cases where a registration request is rejected under this guideline, the database system should return a message to the registrant explaining the reason for the rejection.

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Question -- 1. Mode II antenna height limitation – can Mode II antenna height be greater than 3 meters?Although fixed device antenna height limitations are explicitly discussed in detail in Section 15.709(b)(2), the mode II is only vaguely referenced in Section 15.712(a)(2).If the height is limited to 3 meters, does the FCC anticipate rules changes to that effect?

  • Answer -- There is no limit on the antenna height for personal/portable devices.The Section 15.712(a)(2) mention only applies the fixed device 3-meter height table distance to Mode II device operations; it does not apply the related antenna height specification to Mode II devices.Of course, Model II devices may not be modified and attached to external antennas that were not part of the equipment authorization, see Sections 15.203 and 15.709(b).

U.S. Border Definitions Updated 6/9/14

Guidance -- It was brought to our attention that there is a need to define the border areas of the United States coastlines and land areas bordering Canada and Mexico for calculating available channels for TV white space (TVWS) devices.

The maritime zones established by the United States pursuant to international law and customary law are the “Territorial Sea,” “Contiguous Zone,” and “Exclusive Economic Zone.” These zones are described in a NOAA Office of Coast Survey white paper at http://www.nauticalcharts.noaa.gov/csdl/mbound.htm.

After reviewing the criteria by which the three zones are specified, we conclude that the appropriate zone for definition of the coastal boundary for TVWS protection purposes is the Territorial Sea (i.e., 12 nautical miles from the charted low water line). This is the area in which the U.S. full sovereignty over its terrestrial lands is extended to its internal waters and territorial sea, including the airspace above and the seabed below. The Territorial Sea was historically the “three-mile limit,” however, in 1988, President Reagan by Proclamation extended the U.S. territorial sea to 12 nautical miles.

We are specifying that the TVWS database systems are to use the Territorial Sea limit as the coastal border for purposes of defining TV white space. Geospacial data defining outer limits of the Territorial Sea is provided on the “U.S. Maritime Zones/ Boundaries” page at www.nauticalcharts.noaa.gov/csdl/mbound.htm. The data is provided in two formats on the nautical charts web page via the link titled “Static Data Downloads: ESRI shapefile and KML (Date Updated: 09/13/2013).” The TVWS database systems may use either version as appropriate for their system design.

We also note that the Territorial Sea limit is subject to revision by the Office of Coast Survey based on the accretion or erosion of the charted low water line by the Department of States’ Baseline Committee. We will advise the database administrators of the need to update the Territorial Sea data as new versions may become available.

A file with GIS describing the US-Canadian land area border is available at the following URL: https://transition.fcc.gov/oet/info/maps/uscabdry/uscabdry.zip

A file with GIS data describing the US-Mexican land area border is available at the following URL: http://www.ibwc.gov/GIS_Maps/downloads/us_mex_boundary.zip

Guidance -- This is to provide guidance for the TVWS database administrators in cases where FCC databases are not available for extract operations or all or a portion of the data in an FCC database is found to be corrupt. For example, we recently encountered a situation where some files in the FCC’s ULS daily update were corrupt. It is also possible that an FCC database might not be available for a short period of time due to scheduled maintenance or equipment replacement. Instances where FCC databases are either not available for regular extract of data or certain files are found to be corrupt will, of course, result in a situation where the white space database systems will be unable to make the required record updates to keep their records current.

In such cases, the white space database systems should continue use the data from their most recent successful update. Information concerning scheduled outages and system status may be obtained at the following URLs:

(ULS): http://wireless.fcc.gov/uls/index.htm?job=home

(CDBS): http://licensing.fcc.gov/prod/cdbs/pubacc/prod/cdbs_pa.htm

(EAS): https://apps.fcc.gov/oetcf/eas/

For reference purposes, we note that the FCC database systems are generally scheduled for maintenance on a weekly basis. The overall link to the FCC Network Infrastructure status is at: https://www.fcc.gov/licensing. We also note that these links are transitional and may change in the near future; the database administrators should therefore monitor further announcements from OET or on the FCC website.

We will make every effort to minimize the down time of the FCC databases and/or correct problems. Once the FCC databases are again available, we would expect the database administrators to resume their extracts on their regular schedule. Database administrators may, if they choose, perform an interim extract; however it will not be required that they perform an interim extract to immediately update their records when an FCC database is returned to service or a problem with an FCC database is resolved. We also request that database administrators report any database problems that they encounter to OET as soon as possible so that we can expedite the resolution process.

  • Question -- 8. For TV data, please advise what we should do if neither HAAT, RCAGL or RCAMSL is listed with a record.
    • Answer -- According to the media bureau, all of the CDBS records pertaining to full power TV stations and low power (digital and analog) TV stations have RCAMSL data.The database administrators should use that field for calculating the protected service contours of stations; the other two fields (HAAT and RCAGL) are not needed for those calculations, since HAAT is to be calculated from RCAMSL using the specified terrain database.Data within the CDBS record may be used to reconstruct missing data (for example, using Site Elevation and RCAGL to determine RCAMSL).

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Additional Guidance for Providing Protection to DTS Stations

We have been working on some issues that affect the protection of DTS stations from TVWS devices. To address these issues, we are making some changes to the CDBS for the reference (DT) and DD Site 0 records of DTS stations and to the instructions for providing protection of DTS stations from TVWS devices.

As background, a DTS station is afforded protection from interference in areas where the coverage of the station’s transmitters is within the station’s authorized service contour (based on the engineering data in the station’s DT record) or within the relevant “maximum service area” within the radius specified in the Table of Distances in Section 73.626 of the rules. Areas where one or more of the station’s signals are outside the areas defined by both the authorized contour and distance standard are not protected. This plan for protection of DTS stations coverage is shown graphically on slide 35 of FCC staff presentation at the May 26, 2011 workshop for TVWS database administrators – see (https://transition.fcc.gov/bureaus/oet/whitespace/TVWS_Workshop3/TVWS_Workshop_3_Presentations_5-26-11_v11.pdf). We emphasize that the DT records for DTS stations are “reference” records and do not indicate operating facilities. The DD records (except the record for Site 0) are the operating facilities requiring protection. The reference point coordinates for the “maximum service area” is specified in the record for DD Site 0. Rules allow small (de minimis) extensions of coverage beyond the authorized and maximum service areas and those areas are not entitled to protection. See additional information (particularly the entry for 9/1/11) at https://www.fcc.gov/encyclopedia/white-space-database-administration-q-page.

Recently, it was pointed out to us that there are DTS stations in the CDBS download whose DT record is marked as archived while the related DD records are current. Thus, it is unclear how the TVWS database systems are to compute a “composite contour” for protection if the reference DT record is archived. We are resolving this problem by using a status code of “R” (for reference) for the DT record for licensed DTS stations rather than “A” – these records will no longer be considered archived and instead will be active with the “R” code indicating that they are reference records for DTS stations. When a license application is filed for a DTS operation and the station does not have a previously licensed DTS operation, the DTS facility’s license record will have the “P” code, as that facility has a pending license status, and no “R” coded DT record will yet exist. In these cases, the DT license record with the “C” code should be used to produce the reference contour. (Note that once the DTS license is granted, that “C” coded DT record will change to “R” and can be handled as described above and the DTS license record will change to the “C” code.) Protection of DTS stations should thus be determined by considering the union of the DD records (except Site 0) but excluding areas outside both the DT reference contour and maximum service distance. Also note that these changes do not alter the existing instruction that if a station has both a “C” (license) and “P” (license application) records, the databases are to provide protection using the data in the “P” record.

Next, under Section 73.622(f)(5) of the rules, a station may be allowed to operate with facilities (antenna height and power) that exceed the maximums specified in the rules to provide service up to the same geographic coverage area as the largest station in its market. Some DTS stations are using this rule to provide service beyond the maximum service area and that service is to be protected from interference. These larger maximum service areas are specified for DTS stations as radii/circles that are larger than the radius in the Table of Distances. So, in these cases we need to add the larger maximum service radius to the DTS station’s CDBS records. To do that, we are adding the extended maximum service radius to a DTS station’s DD record for Site 0 in the field “predict_coverage_area” of the tv_eng_data file. If this field is populated (not “0” or null), the TVWS databases should use the value therein as the maximum service area radius rather than the radius in the Table of Distances.

Guidance for Providing TVWS “Keyhole” Protection

Clarification regarding the proper application of “keyholes” for protecting the receive channels of TV translator/LPTV stations, TV Translator Relay stations, and MVPDs.

  • "Keyhole" Guidance [Acrobat] (updated on 4-2-14)

Canadian TV Stations Data Implementation Information

We’ve received a number of questions on how to use and implement the Canadian TV station data from Industry Canada (IC). We’ve contacted IC and coordinated the questions and responses to them with IC. The questions and responses are:

1. Are we to use the same protection for these stations as we do for US stations? I think you mentioned in a workshop that this is the case, but I am just verifying.

  • Response: Canadian stations receive the same protection as U.S. stations, except that the protected (service) contours of Canadian stations are assumed to stop at the U.S.-Canada common border. So, using the new distance separation table from the TVWS 3rd MO&O, the maximum required separation between a TVWS device and the U.S.-Canada border would be 31.2 kilometers.

2. How do we determine if a station is a digital or analog station? I see that callsigns have DT, TV, etc. appended to them, but I don't see a separate service code field, or something similar. If we are to use the appended two char codes, which indicate digital and which indicate analog. Some stations don't have a two char code appended, what do we do for those?

  • Response: It’s necessary to know whether a protected TV station is analog or digital in order to determine the relevant contour value. It appears that all DTV stations have “-DT” as part of their callsign. For the time being, all non –DT stations may be assumed to be analog.

    There is also a “modulation” field in one of the database (dbf) files that specifies the type of operation (analog or digital). The TV modulation information is contained in the TVstatio.dbf table in column ERPATA and is coded as 0=Analog; 1=Digital and 2=Post-transition (i.e., Digital). So if the ERPATA value is 1 or 2, the station is a digital station. If that dbf is not present, you should base the analog/digital determination on the callsign.

3. For analog stations, which ERP level should we use for contour generation, Visual Peak, Visual Average, Aural Peak, Aural Average, Total (sum of the two) peak, Total Average, or something else?

  • Response: Visual Peak power (ERP) is used for both analog and digital station contour projection. There are a few records with “0” Visual Peak power and a non-zero entry for Visual Average power. For those records, assume that the supplied average power value is also the peak power. Peak power is the maximum power in any direction radiated by a directional antenna, while average power is the mean value across all azimuths. For omni-directional stations, peak and average are the same.

    There are 32 records with “0” ERP for both Visual Peak and Visual Average. In these cases where both the Visual Peak and Visual average power are zero, assume the Visual Peak power is 1 kW.

4. What ERP do we use for digital stations? It looks from the records that some digital stations only specify Visual ERP as non-zero. I haven't fully analyzed the data, so I don't know if this is always true.

  • Response: See above. Use Visual Peak power for digital station contour projection.

5. Do we ignore tilt angle (as we do in the US) and associated ERPs at tilt angles?

  • Response: You may ignore tilt angle.

6. There seem to be many stations that have both HAAT and HAGL equal to 0, which could cause some problems in the contour distance calculation. Should we assume some minimum non-zero height?

  • Response: There are 88 records that have no useful entries for determining antenna height (i.e., no entry for HAAT, RC, or AGL). 26 of those have no entry for ground elevation, either. For those records, take the DEM height as the true ground elevation and assume that the antenna is located 30 meters AGL.

7. At the end of the provided document on use of the Canadian TV station data is a table for the Television Class of Stations. In this table, there is a code LVP which does not appear in the data, but the code VLP does appear in the data, so we assume the letters were transposed.

  • Response: On the table describing the classes of stations at the end of the Canadian TV station data document, the “LVP” class should be “VLP”. This has been corrected in the Canadian TV station data document on the OET TVWS website.

2. Also in this table, no description is provided for the code D, we assume these are also NTSC stations.

  • Response: The “D” code indicates NTSC Class D low power TV stations.

3. In the included TV station data (file tvstatio.txt) of 2146 records, 606 stations have a channel number higher than 51, we assume that these stations can be ignored.

  • Response: Stations on channels above channel 51 should be ignored.

OET also noticed that there are 151 U.S. stations in the database in addition to the Canadian stations. The U.S. stations should be ignored. The most reliable way to distinguish Canadian stations from U.S. stations appears to be use of the province code field in the table PROVINCE.dbf (the Canadian province codes are AB, BC, MB, NB, NF, NS, NT, ON, PE, QC, SK, YT).

Section 15.712(b) of the rules provides that the receive sites of low power stations may be registered in the TVWS databases only if they are no farther than 80 km outside the nearest edge of the relevant contours, 47 C.F.R. § 15.712(b). We have observed, however, that the records for some low power TV stations (including TV translators, low power TV and Class A TV stations) in the CDBS specify receive channels indicating that the stations’ re-transmit the signals of stations whose nearest contour edge is more than 80 km from the low power station’s receive site. A question has arisen as to how the database administrators are to treat the receive site data in the CDBS where the nearest edge of the contours of the received stations are farther then 80 km from the low power station.

In such cases, the TVWS databases should not provide protection for reception of that re-transmitted station, i.e., the databases should disregard the receive channel data in the CDBS record. We note that receive sites of multiple video program distributors (MVPDs) are subject to this same limitation, but MVPD receive sites are not recorded in the Commission’s databases. Also, in the Second Memorandum Opinion and Order in the TVWS proceeding, ET Docket No. 04-186, 25 FCC Rcd 18661, the Commission indicated that it would consider waivers of this rule for both low power TV stations and MVPDs. The TVWS database administrators must provide protection of received/re-transmitted stations where such waivers have been granted. Waivers of this rule will be issued by the Commission in an Order.

  • Question -- Requests for waiver of the provisions in Section 15.712(b) of the rules that limit protection for MVPD, TV translators, low power TV stations and class A TV station receive sites to those located outside of and within 80 km of the service contours of the received stations – how and when will you communicate the list if waivers are granted?
    • Answer -- Decisions on the waiver requests will be made by the Commission in an Order. The Order will be publicly released and we will also send it to the database administrators and others who attended the workshops. We're working on an Order; hopefully it will be done relatively soon.
  • Question -- Temporary BAS links – Rule 74.24 states that these temporary links shall not exceed 720 hours annually. I assume we do not have to check for adherence to the rule on an annual basis. We would just limit the registration to 720 hours for that instance. Please confirm.
    • Answer -- The TVWS database administrators do not need to check to make sure that a temporary link is on compliance with the rules. If it's in the database, administrators can assume that it is authorized.
  • Question -- How are the TV white space database administrators to treat Special Temporary Authorizations (STAs) for broadcast television stations in the Media Bureau’s Consolidated Database System (CDBS) with regard to protection from TV white space device? Updated 12-3-2014
    • Answer –- An engineering STA authorizes a station to temporarily use transmission facilities that are different from its licensed facilities. Engineering STAs can be identified by the presence of engineering data in a station’s CDBS STA record. A station using the transmission facilities authorized by an engineering STA generally serves a geographic area that is different to varying extents from that served with the transmission facilities specified on its license records (license or license-to-cover (LTC)). Also, an engineering STA can authorize operation on the same channel as a station’s license/LTC or on a channel different from the station’s license/LTC.

      In most cases, engineering STAs are for the same channel as the station’s license/LTC and the station does not operate the facilities specified on its license while it is operating under the STA. However, a station with an engineering STA can return to operation on its license/LTC facilities at any time during the period of the STA (i.e., before the STA expires). Since the CDBS/LMS license process does not provide for stations with engineering STAs to notify the FCC when they return to operation on their license/LTC facilities, it is not generally possible for the TVWS databases to determine whether a station is operating on its license/LTC or STA facilities. To ensure that stations with engineering STAs on the same channel as their license/LTC facilities are protected on both their license/LTC and facilities, the TVWS databases should protect both the license/LTC and STA service areas for such stations during the term of the STA.

      A silent STA is issued to a station that has requested to remain silent for one reason or another. In these cases, the status of the stations will change to licensed and silent in CDBS. Silent STAs do not include engineering data. The TVWS databases should not protect a station’s service area if the station’s status in CDBS is licensed and silent.

      A station may in some cases operate its licensed facilities along with its engineering STA facilities, that is it may operate separate facilities under both its license/LTC and STA. For example, a station with an STA that authorizes low power operation on a channel different from its licensed channel might also continue to operate its normal licensed service. In these cases, the TV white spaces databases should also protect both the station’s STA and licensed facilities.

      We have modified our logic for extraction of records for active TV stations from the CDBS to include STAs and STA extensions that must be protected as described above. The revised extraction logic is available on the OET TVWS website under the heading “CDBS Data Extraction Logic,” see https://www.fcc.gov/encyclopedia/white-space-database-administration.

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Workshop Guidance

Workshop Guidance
  • Question -- In Workshop 2, slide 27 discussed the topic of which DTS record/station to use when that station is re-transmitting to a receive site. A “strongest server” method was discussed but my notes indicate that you needed to formalize this process. Would you confirm that this is the correct approach and expand on the technique?
    • Answer -- As discussed during the April 20, 2011 TV Bands Database Administrator Workshop, the “strongest server” technique is to be used to determine protection of a DTS station from white space device operations at a particular location. In this context, for locations outside the noise-limited contour of any DTS station, the “strongest server” is that DTS server which produces the noise-limited contour that is closest to the location being examined.(Workshop2 presentations See Slide III-27.)

      With respect to a DTS station, the total service area is the union of the individual DTS service areas (i.e., areas within the relevant noise limit contours of all DTS servers), excluding those areas outside both the “authorized service area” and the “maximum service area” for the DTS station.The “authorized service area” is defined in Appendix B of the Second MO&O on Reconsideration of the 6th MO&O to MB Docket 87-268 or in a subsequent order defining that area for a particular station.The “maximum service area” is a radial distance from the transmitter site defined in Section 73.626(c).(Second MO&O on Reconsideration of the 6th MO&O, See Appendix B), & (Workshop3 presentations See Slide 35.)
    • Question -- Equipment classes – In Workshop 1, you indicated that there were two white space equipment classes at that time:WSS and WSG. We noticed that the EAS database also includes WG2, WGF, WS1, WS2, WSF. I assume we will need to consider those as well and regularly check for additional codes. Please confirm.
      • Answer -- Yes, the EAS will use those codes to the TVWS devices going forward and the database administrators should regularly look and check for them as well as other new codes that may be used.There may be multiple entries for a device if applications for permissive changes have been filed with the Commission subject to the requirements of Section 2.1043. The specifics of the web service are described in KDB Publication 953436 (available at www.fcc.gov/labhelp).
    • Question -- 7. In Workshop 3, you updated the radio astronomy coordinates but did not list Sugar Grove in the table. You indicated at that time that you would also verify those coordinates. Do you have those coordinates?
      • Answer -- The coordinates for the Naval Research Observatory in Sugar Grove, WV are 38° 30’ 58” N Latitude and 79° 16’ 48” W Longitude.

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  • Question -- Some records in the ULS for PLMRS/CMRS licenses on frequencies within TV channels 14-20 (470-512 MHz) have only a “text-based” area of operations (e.g., “Nationwide”, “CONTINENTAL SOUTH OF LINE A WEST OF LINE C US”, “48 KMRA 34-16-05.0 N 118-14-13.3WLos Angeles, CA”), rather than specified geographic coordinates in the latitude and longitude fields.How are these licenses to be treated with respect to protection from TV white space devices? Posted
    • Answer -- The PLMRS licenses identified by such records are for operation of 1) equipment for developmental and demonstration purposes or 2) mobile facilities associated with a base station that is separately licensed.For the former case, the Commission does not protect developmental and demonstration operations that are conducted on an ad hoc basis whereby the location of the operations are not specifically defined.Therefore, those records will not be afforded interference protection from TVWS devices.And for the latter situation, the protection afforded by the associated base station already provides protection to the mobile operations.Thus, the PLMRS records for licensed mobile operations on channels 14-20 that specify a text-based area of operations will be afforded protection from TVWS devices through their associated base station license recordsrather than a separate (and duplicative) regime of protection.The TVWS database systems do not need to include the records for any of the above licenses.
    • Question -- Section 15.713 (h)(3)(iv) of the TVWS rules, which requires that TVWS databases include information on the metropolitan areas listed in Section 90.303(a) in order to protect PLMRS/CMRS operations on channels 14-20 in those areas, contains an error. This section requires that the licensee’s call sign be included in the databases.

15.713(h)(3)(iv) as of 7-20-2011 states:
Metropolitan areas listed in §90.303(a) of this chapter.
(i) Region name.
(ii) Channel(s) reserved for use in the region.
(iii) Geographic center of the region (latitude and longitude in NAD 83).
(iv) Call sign.

      • Question -- How should the TVWS databases address this requirement?
        • Answer -- The call sign requirement in Section 15.713(h)(3)(iv) is an unfortunate error that somehow crept into the rules – there are no call signs for metropolitan areas.The database administrators should ignore that portion of the requirement.
      • Question -- Are database administrators required to provide adjacent channel protection to BAS point-to-point fixed links occupying channel 52 (698-704 MHz) (see for example WPOT901)? Similarly, are TVWS database systems required to afford adjacent channel protection to other types of facilities such as waivered/licensed PLMRS/CMRS facilities that may be found on channel 52?
        • Answer -- Database systems are not required to provide adjacent channel protection to legacy services from the TV bands that are continuing to operate on channel 52.

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Tuesday, April 22, 2014