NAB Engineering Handbook: Dane Ericksen on BAS Frequency Coordination

August 29, 2017

This Q&A with Dane Ericksen, P.E., is one in a series of conversations Radio magazine will have with authors who contributed to the recently released 11th edition of the “NAB Engineering Handbook,” published by Taylor & Francis.

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Dane Ericksen

Ericksen is co-chair of Engineers for the Integrity of Broadcast Auxiliary Services Spectrum and a consultant to Hammett & Edison Inc. in San Francisco. He serves on the SBE Certification Committee and as SBE Chapter 40 Secretary.

Radio World: You authored the chapter on BAS frequency coordination. For readers not familiar, what is that exactly; and how does the topic affect TV and radio engineers?

Dane Ericksen: Chapter 2.3, Frequency Coordination for Broadcast Auxiliary Services, should be of interest to radio and TV broadcast engineers because BAS stations represent important infrastructure for broadcaster stations. They include studio-to-transmitter (STL) microwave links, two-way remote pickup (RPU) frequencies, and low-power auxiliary wireless microphone frequencies. Most radio and TV stations have multiple BAS licenses.

RW: How has information in this topic changed over the past several years; what’s new in the chapter from any previous editions?

Ericksen: My updated chapter on BAS frequency coordination addresses the reality that many frequency bands that were originally for the exclusive use of broadcast station licensees and broadcast network entities are now open to nonbroadcast licensees. The entire 2,025–2,110 MHz TV BAS band is now shared with Department of Defense (DoD). Earth Exploration Satellite Service (EESS) licensees are increasingly using 450.00 MHz and 2 GHz TV BAS frequencies for their telemetry, tracking and command (TT&C) uplinks. The 950 MHz Aural BAS and 7 and 13 GHz TV BAS bands are now shared with Part 101 fixed service (FS) stations.

Grandfathered TV BAS Channel A10 stations at 2,483.5–2,500 MHz must now share that channel with Globalstar’s Terrestrial Low Power Service (TLPS) stations (access points, or APs) at 2,483.5–2,495 MHz. (TLPS is an ancillary terrestrial component (ATC) use of Mobile Satellite Service (MSS) spectrum, which was originally allocated for space-to-earth use, not terrestrial use).

And the FCC has just issued a Notice of Inquiry (NOI), General Docket 17-183, proposing “flexible use” for “mid-band” spectrum between 3.7 and 24 GHz, which, it turns out, includes the entire 6.5 and 7 GHz TV BAS bands. This “flexible use” includes the possibility of unlicensed, Part 15, transmitters.

RW: Can you share one specific tip or piece of information about BAS frequency coordination, that you think readers might not know, as an example of the kind of useful information found in the handbook?

Ericksen: My principal “tip” concerning BAS frequency coordination is that accuracy for a BAS station’s technical data is important. This is because the 7 and 13 GHz TV BAS bands, and also the 950 MHz Aural BAS band, are now shared with Part 101 FS stations. Some Aural and TV STL licenses are missing important data such as receive-end geographic coordinates, receive-end antenna height, make and model of the receive-end antenna, and in some cases even the polarization of the link.

These omissions were mostly a consequence of the FCC converting BAS licenses from the Media Bureau to the Wireless Telecommunications Bureau (WTB). Part 101 FS newcomers often have no familiarity with STL paths, and base their applications solely on what is in the WTB’s Universal Licensing System (ULS).

Also, frequency coordination for fixed, point-to-point links is now accomplished pursuant to the Part 101 Prior Coordination Notice (PCN) protocols; except at 2 GHz, local SBE-affiliated BAS frequency coordinators are no longer involved when it comes to the frequency coordination for fixed-link stations.

EIBASS, NAB and SBE have been working with the BAS Subcommittee of the National Spectrum Management Association’s Working Group 3 (Coordination Procedures) to establish band-sharing protocols. Indeed, NSMA Recommendation WG 03-17.001, Fixed Service Frequency Coordination for the Broadcast Auxiliary Service and Cable Television Relay Service Bands of 6875–7125 MHz and 12700–13150 MHz, has recently been posted to the NSMA website.

In 2014, NSMA sent a detailed letter to the FCC documenting the data base errors, and requested a blanket waiver to allow stations with the “data converted” annotation in their ULS history to provide the missing data without having to first submit an updated PCN, and to waive the filing fee. In February 2016, there was a follow-up, in-person meeting at the FCC regarding the NSMA letter. Unfortunately, the NSMA/EIBASS/NAB/SBE effort to purge the ULS of incorrect or missing data for Part 74 BAS stations remains a work in progress.

RW: Did you come across any other interesting discoveries or unexpected findings as you did the research for your chapter?

Ericksen: My biggest unexpected finding was that the cause of missing data in the ULS for Part 74 fixed-link stations was almost entirely due to migrating existing fixed-link Aural and TV STL records into the ULS. Documentation of this was provided as attachments to the 2014 NSMA letter, which is available in the WT Docket 10-153 record in the Electronic Comment Filing System (ECFS). That documentation was an eye-opener for me.

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