DTV Signal Measurement Debate Continues
August 31, 2006
The debate between EchoStar and broadcasters continues as the proceeding to determine TV field strength methodology draws to a close.
In dispute are the procedures for making field strength measurements for determining whether a house receives network digital off-air programming from a television, as defined by Congress in the Satellite Home Viewer Extension and Reauthorization Act (SHVERA). The major arguments have been thoroughly discussed in previous RF Report and RF Technology columns starting with comments filed in the FCC's Notice of Inquiry.
Not surprisingly, EchoStar opposed many of the comments NAB, MSTV and network affiliates filed in the proceeding, (see RF Report for Aug. 17, 2006 for details on broadcasters' comments). EchoStar said that broadcasters are incorrect in stating that dipoles are more expensive than gain antennas, since the broadcasters were comparing a calibrated NIST-traceable dipole with gain antennas that do not have NIST-traceable calibration.
EchoStar said that the FCC should not modify testing procedures to conform to DTV planning factors, when the DTV marketplace doesn't match those planning factors.
Further, according to EchoStar, "This would be a recipe for unrealistic determinations as to whether consumers can receive an adequate over-the-air digital picture. Rather, the Commission should ensure that the testing procedures more closely reflect the DTV marketplace so that subscribers who cannot receive an adequate over-the-air network signal can receive a distant network signal as Congress intended." EchoStar said that dipole antennas more closely resemble the characteristics of indoor antennas.
EchoStar argued for flexibility in the choice of field strength measuring instruments and said the "Best Practices" offered by the broadcasters "should not be adopted by the Commission in any form because they are likely to confuse and are unduly cumbersome."
EchoStar discounted the value of the MSTV spreadsheet for field measurement calculations, saying it "should not receive any Commission imprimatur without prior examination and opportunity for comment."
EchoStar joined DirecTV and the CEA in supporting an option to use a predictive model for qualifying subscribers, but said the existing Individual Location Longley-Rice predictive model should not be used "without significant modification." EchoStar disagreed with comments from DirecTV supporting use of the American Radio Relay League to arbitrate disputes over tester qualifications. EchoStar said that, although in principle this was a sound idea, there was concern that such a dispute resolution mechanism could potentially slow things down and could further exacerbate problems hampering the waiver and testing processes.
EchoStar continued its efforts to have the FCC set a higher signal strength requirement for SHVERA field measurements than those predicted using F (50, 90) statistics, since, the company argued, field measurements represented the median value (50 percent of the locations 50 percent of the time) instead of the 90 percent time variability used in DTV signal strength predictions.
In their reply comments to the commission, NAB and MSTV, along with the ABC, CBS, Fox and NBC affiliate associations, stated their opposition to EchoStar's plans to use its own employee-installers to perform signal testing.
"The Commission should be careful not to endorse or in any way appear to 'bless' EchoStar's proposal for ex parte testing using procedures of EchoStar's devising," the groups warned. They also said that there was no reason for the FCC to endorse a procedure that had no legal significance, did not have to comply with rules for ensuring accurate results and might be performed by unqualified and biased testing personnel.
The broadcasters said the FCC has already rejected EchoStar's proposal to modify the minimum digital signal levels specified so that more households will be considered "unserved." NAB said the latest version of EchoStar's proposal reflected a misunderstanding about FCC methodology for determining analog and digital TV signal levels. The organization also said Congress required that the FCC continue to use signal strengths already specified in official documents.
NAB and the broadcasters also opposed the request from EchoStar to "allow testers to choose locations different for digital signals than those specified in the Commission's long-standing rules for site testing of analog signals." The groups said, "Given the potential for gamesmanship in the testing process, and the fact that a broadcaster may not always be able to have an observer present to prevent such abuses, the Commission should decline EchoStar's invitation."
The broadcasters also reject altering test procedures to account for "alleged shortcomings in receiver performance." They said the commission's test results reflect a worst-case scenario and in any event, since EchoStar itself provides set-top boxes to its customers, it can "readily ensure that the over-the-air digital receivers in its boxes are of good quality."
As I noted in one of my earlier reports on this debate, even if you disagree with the comments, the engineering exhibits attached to them provide worthwhile insight on terrestrial DTV reception and are worth reading. You can access all comments and exhibits filed in the Notice of Proposed Rulemaking proceeding by visiting the FCC Search for Filed Comments Web page and entering the numbers "06-94" in the first box, which is labeled "Proceeding".