RFI_Survey_SOW_DRAFT_v.4.docx

Statement of Work (SOW) For Radiosonde Frequency Migration Project (RFMP) Radio Frequency Survey

(Acquisition Sensitive)

DEPARTMENT OF COMMERCE

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION

NATIONAL WEATHER SERVICE

OFFICE OF OBSERVATIONS

1325 EAST WEST HIGHWAY

SILVER SPRING, MD 20910

V 0.4

Contents

1 Introduction

1.1 Background

Since the late 1930's the NWS has measured vertical atmospheric profiles of pressure, temperature, relative humidity, and wind velocity. The NWS has primarily used balloon-borne sensors for atmospheric observations, as well as meteorological satellites, radar, wind-profilers, and aircraft observations. Atmospheric observations are a key source of data for weather forecasts and related products including severe weather watches and warnings and climate forecasts.

‘Upper air’ is defined as the region above the surface of the earth to a height of 110,000 feet into the atmosphere. ‘Upper air measurement’ is the measurement of atmospheric conditions including temperature, humidity, wind velocity and barometric pressure within this region. Upper air measurements are usually accomplished using a measurement device known as a ‘radiosonde’, flown by a balloon ascending through the atmosphere and following the wind direction. Balloons with radiosondes are flown at least twice a day at 00 UTC and 12 UTC, as well as at ad-hoc launches during or before severe weather. The information captured is transmitted by radio waves from the radiosonde to the ground and then is transmitted to computer modeling and forecasting systems to develop watches, warnings and forecasts both at NWS weather forecast offices and NWS national centers.

Figure 11 The NWS Upper Air radiosonde process As part of a presidential initiative to repurpose Federal radio spectrum for private sector use, the radio spectrum NOAA uses to operate Geostationary Operational Environmental Satellites (GOES), between 1695 MHz and 1710 MHz, will be reallocated for shared use by commercial wireless communications service providers. This shift has created an overlap with frequencies currently used by radiosondes, operating on frequency channels tuned between 1675 and 1683 MHz. The NWS has chosen to replace the existing radiosonde observations network with a new network using the 400-406 MHz frequency range to avoid causing interference with meteorological satellites and industry. See Appendix B, U.S. Frequency Allocations, for more information.

1.2 Objectives

The National Oceanic and Atmospheric Administration (NOAA), National Weather Service (NWS) has a requirement for upper air radiosonde operations to relocate from the existing 1675 -1683 MHz frequency band (1680 MHz band) to the new 400.15-406 MHz frequency band (403 MHz band).

The Radio Frequency Migration Project (RFMP) was initiated by NWS to manage and oversee the frequency relocation of the upper air network to the 403 MHz band. Before relocating radiosonde systems to the new frequency band, it is the intention of the RFMP to have radio frequency (RF) surveys conducted at all upper air observation locations for analysis of the RF environment in and around the 403 MHz band.

2 Statement of Work

2.1 Scope of Work

The NWS is seeking a service contract for performing on-site RF surveys for the RFMP. This Statement of Work (SOW) describes the RF survey and analysis work (Project) to be performed by the survey contractor (Contractor) in executing the contract.

The Project will consist of a kickoff conference followed by the Contractor conducting 64 individual surveys at NWS upper air sites in the Continental United States (CONUS). See Appendix A, Survey Locations, for more detail. The Contractor shall execute surveys following a timeline developed in coordination with the NWS and meet NWS requirements for survey execution and data production. The Contractor shall provide periodic updates on the survey execution and deliver RF survey reports regularly throughout the survey. The contractor shall determine and arrange all necessary survey site travel and local support services to conduct the RF surveys.

The following figure shows the MROS RF Survey contract schedule:

Figure 201 MROS RF Survey Contract Schedule

2.2 Contract kickoff conference

Thirty days after award a contract kickoff conference will be held at NWS Sterling Field Support Center in Sterling, VA. The objectives of the kickoff include:

· Provide Contractor with background information on RF interference in radiosonde systems.

· Discuss radiosonde observation system antenna siting guidelines.

· Review Contractor procedures for survey execution.

· Review reporting requirements and format.

· Review and respond to Contractor questions.

2.3 Survey Execution

The Contractor shall perform four primary areas of survey work for the successful completion of this contract:

· Measure and document the RF environment at the site.

· Investigate identified signals both in and near the 403 MHz band.

· Provide in-band radiosonde system channeling recommendations.

· Identify and propose an optimal site for future 403 MHz band antennas.

2.3.1 Measurement and documentation of the RF environment

The Contractor shall perform an assessment of the surrounding topology at the survey site. This shall include:

· Identifying potential obstructions.

· Determining if there are any incumbent transmitting signals that are potential sources of interference.

· Photograph the site and provide sufficient imagery and diagrams to thoroughly depict unique features and potential obstructions.

The Contractor shall record the RF environment:

· Record for a minimum period of 24 hours while attempting to cover the most active RF period of the week as determined by NWS personnel.

· Interview local personnel and document all known competing 403MHz band activities.

· Measure and identify all RF activity between 350 – 450 MHz. Record transmission strength of all RF activity between 395 – 411 MHz.

· Perform detailed measurements and identify all signal activity between 400 – 406 MHz, including a general noise floor assessment and all in-band deviations from it.

· RF surveying shall include measurements during synoptic times (0 and 12 UTC).

Recommended equipment for recording the RF environment is listed in Appendix C, Equipment and Tools.

2.3.2 Investigation of identified signals

The Contractor shall capture detailed measurements of the identified interference. The Contractor shall assess transmission characteristics including power, frequency, and signal profile.

The Contractor shall reference Government Master File (GMF) and Federal Frequency Commission (FCC) licensing lists for source determination. If unable to determine sources through GMF or FFC lists, the Contractor shall perform triangulation to identify signal sources.

2.3.3 Developing in-band channeling recommendations

To develop recommendations for in-band channels, The Contractor shall:

· Identify and document areas of the 403 MHz band, of 250 KHz or greater width, with the least noise that should be prioritized for operational channel selection.

· Identify areas of the 403 MHz band, of 250 KHz or greater width, where the noise floor is elevated but still usable for radiosonde operations.

· Identify areas of the 403 MHz band, of 250 KHz or greater width, which should be avoided due to competing in-band RF activity.

See Appendix D, Channeling Guidelines, for more details.

2.3.4 Identification of optimal siting for future 403 MHz antennas The Contractor shall conduct siting activities using NWS RFMP guidance and guidelines for the siting of 403 MHz radiosonde observation system antennas to:

· Identify two optimal antenna installation locations, a primary location and a secondary location, with the lowest RF interference potential.

· Perform RF survey measurements from the identified optimal primary and secondary siting locations (within 200 feet of signal processor).

· Photograph the site and provide sufficient imagery and diagrams to thoroughly depict siting location for future antennas.

See Appendix E, Antenna Siting Guidelines, for more details.

2.4 Deliverables

Contractor deliverables shall include the following:

· Pre-survey items including questions for kickoff conference, RF survey equipment, survey schedule, report templates and execution procedures.

· RF survey reports for each survey executed.

· RF survey interference notifications for surveys found to exhibit RF interference.

· RF survey completion report.

· Bi-weekly project update meeting minutes.

All documents delivered by the Contractor shall be in softcopy MS Office format including data in Excel or CSV format and reports in Word format.

2.4.1 Pre-survey Items

The Contractor shall provide the following to the NWS no later than 20 days after award of contract:

· A list of pre-survey questions for NWS on project procedures and requirements.

· A proposed list of equipment to be used for RF surveys.

· A proposed RF survey report template.

· A proposed site visit sequence and survey execution schedule.

· A proposed survey execution procedure.

2.4.2 RF Survey Reports

Each RF survey shall be documented in a RF survey report, and submitted to NWS within 2 weeks of the on-site survey completion. Each RF survey report submitted by Contractor shall be evaluated and approved by the NWS for acceptance. Report deficiencies shall be corrected and resubmitted for approval within 2 weeks of receipt of deficiency report from NWS. The survey report shall contain:

· An assessment of the surrounding topology at the survey site including potential obstructions and incumbent transmitting signals that are potential sources of interference.

· Site imagery and diagrams thoroughly depicting unique features and potential obstructions.

· A record of the site RF environment for a minimum period of 24 hours during the most active RF period of the week including measurements during synoptic times (0 and 12 UTC).

· Interviews of local personnel documenting all known competing 403MHz band activities.

· A list of all RF activity identified between 350 – 450 MHz.

· Recorded transmission strengths of all RF activity between 395 – 411 MHz.

· Detailed measurements of RF activity between 400 – 406 MHz, including a general noise floor assessment and all in-band deviations from it.

· Spectrum analyzer screen captures for 350 – 450 MHz, 395 – 411 MHz, and 400 – 406 MHz

· Interference sources determination from Government Master File (GMF) and Federal Frequency Commission (FCC) licensing lists, or, alternatively, sources determined by triangulation.

· Detailed measurements of identified interference with transmission characteristics including power, frequency, and signal profile.

· Areas of the 403 MHz band, of 250 KHz or greater width, with the least noise that should be prioritized for operational channel selection.

· Areas of the 403 MHz band, of 250 KHz or greater width, where the noise floor is elevated but still usable for radiosonde operations.

· Areas of the 403 MHz band, of 250 KHz or greater width, which should be avoided due to competing in-band RF activity.

· Two identified optimal antenna installation locations, a primary location and a secondary location, with the lowest RF interference potential.

· RF survey measurements from the identified primary and secondary siting locations.

· Site imagery and diagrams thoroughly depicting and identifying the primary and secondary siting locations.

· RF measurement files in comma separated value, Excel, or text formats including date and sequential time of measurements, GPS location, and measurements in dBm.

2.4.3 Periodic Project Updates

The Contractor shall provide periodic (bi-weekly) updates on the planning, coordination and scheduling of survey execution and delivery of RF survey reports. Updates shall be delivered as reports to the NWS and via conferences with NWS (in person or via video or teleconferencing) by the Contractor project manager. The Contractor shall provide conference meeting minutes, including issues raised and action items, to the NWS within 3 business days of each update conference.

2.4.4 RF Interference Notifications

Within 48 hours after completion of each RF survey, the Contractor must provide NWS with a summary report of RF interference detected in the 403MHz band at the survey site. The notification must contain graphical plots of noise frequency and intensity including spectrum analyzer screen captures for 350 – 450 MHz, 395 – 411 MHz, and 400 – 406 MHz, as well as information on possible noise sources.

2.4.5 RF Survey Completion Report

The Contractor shall provide a report upon project completion or within 30 days of the final site survey containing results from each survey and a project summary. The report shall be delivered electronically in MS Office (Word and Excel) format.

Appendix A Survey Locations

Appendix B U.S. Frequency Allocations US Frequency Allocations

Appendix C Equipment and Tools

The following are recommended equipment and tools to be utilized in Contractor RF surveys:

Input attenuation (dBm) Resolution bandwidth - RBW (KHz/MHz) Video bandwidth – VBW (KHz/MHz) Sweep time in milliseconds

Appendix D Channeling Guidelines

The following represents an example of a channeling procedure:

RF sweep from 400-406 MHz

Figure E01: Detected frequencies in 400-406 MHz band

Identification of major spikes

Table E-1: Avoid Frequency list

Develop the channel recommendation

Develop a recommendation for the 403 MHz band showing good, useable and to-avoid regions:

Figure E02: Recommended operational channels

Appendix E Antenna Siting

The Contractor will use engineering best practices for the placement of an antenna and will work with the NWS RFMP program office and on-site WFO location technicians to determine the optimal position of the antennas when conducting the RF survey.

The following antenna siting guidelines should be followed:

· Maximum cable run length of 200 ft. from the receiver installation point within the WFO

· Antenna installation options, in order of preference, include:

1- WFO rooftop 2- UAIB rooftop 3- Existing towers 4- New tower

· Avoid installing the receive antenna in front of any existing directional antenna main lobe. The safe distance will depend on the antenna shape, transmitted power, gain and line of sight.

· The recommended installation location should be on the null zone of the existing directional antenna.

· Choose an antenna location that has a clear view of the sky down to the horizon in all directions if possible.

· Higher elevation areas such as rooftops are beneficial for staying clear of obstructions.

· The antenna should be installed so that it is not screened by large obstacles, such as buildings, thick forest, or high metal masts.

· Avoid installing on metal roofs and other corresponding large surfaces. Metal structures reflect signals in some instances, causing multipath interference.

Appendix F Recommended RF Survey Steps

The following are recommended guidelines for the RF Survey process:

· Arrange with the chosen WFO personnel to support the RF survey and determine the best time for the visit.

· Obtain from the local WFO POC the communications devices and the associated maximum transmitted powers and operation frequencies.

· Check the Government Master File (GMF) and Federal Frequency Commission (FFC) for the incumbent authorized sites location, operational frequencies, maximum transmit powers, antenna type, height and any related useful data for RF survey.

· Conduct RF remote analysis to assess the RF environment and sites line of sights before surveying.

· Arrange with the local personnel the best location to set up both receive antenna and RF spectrum analyzer (rooftop, back yard, existing or new tower, and/or the upper inflation building).

· Ensure that the measurement devices are calibrated (spectrum analyzer).

· Set up the receive antenna and associated system on the designated location.

· Document the receive antenna GPS coordinates and elevation.

· Capture and document the four cardinal directions (North, East, South and West).

· Start measuring the various ranges of frequencies starting at 350-450 MHz to assess the adjacent RF environment.

· Capture and save the 350-450 MHz measurements and the interval timing.

· Measure and document the second frequency range of 377-420 MHz.

· Measure the active received spikes within 400-406 MHz if possible during the synoptic time (0 and 12 UTC).

· Identify the active frequencies sources and compare them with the GMF/FCC records.

· Categorize the received RF signals into three categories: operational frequencies that are relatively interference free, avoid frequencies that are very noisy channels. Use channels that are relatively noisy frequencies with caution.

· Document the three frequency categories and update the recommended operational, avoid and use with caution frequency chart.

· Document and report any major adjacent or co-channel interference.

· Confirm the optimal permanent receive antenna locations.

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