RF CURRENT



Welcome to RF Current, a weekly electronic newsletter focusing on Broadcast technical and F.C.C. related issues. This newsletter is part of The RF Page @ www.transmitter.com, a web site devoted to TV Broadcast RF engineering. For more information see the What is... guide to the R.F. Page site.

Issues are dated each Monday, although recently I've needed an extra day or two to complete each issue. Articles may be posted earlier if time permits or if there is a major, breaking story.

<<< Back to October 11 - Issue 186

October 18, 1999 - Issue 187 Final Edition

DTV - Hauppauge Launches WinTV-D - Low Cost DTV Receiver for PC (Oct. 18)
Low cost DTV receiver products are starting to become available. Hauppauge Digital, Inc. launched its WinTV-D board for PCs using Windows 95, 98 or NT. Hauppauge claims it is the first DTV receiver board for PCs that allows the reception, decoding and display of all 18 ATSC formats in a resizable window on the PC display. It also includes a AC-3 Dolby Digital(tm) audio decoder with outputs for up to five speakers. It is also able to receive analog TV broadcast. Hauppauge said the board will be available in Best Buy stores nationwide this week and will sell for approximately 300 dollars (US). In addition to being viewed on the computer's monitor, the DTV signal may also be viewed on a large-screen analog TV set using an output provided on the WinTV-D board. Taking advantage of the fact the ATSC DTV signal is compressed to a 19.4 Mbps data stream, the WinTV-D board allows recording DTV programs to a hard drive.

Jeff Cadet, a TV DXer, tested a prototype of the WinTV-D board. Check out Digital Television's First DX Photos for DTV signals captured by Jeff. Images include one from WDIV-DT, channel 45, in Detroit, Michigan, 416 miles from Jeff's MaComb, Illinois location. Other images show reception of stations in Chicago IL, Madison WI, South Bend IN, and Indianapolis IN.

More information can be found on the Hauppauge home page and in the WinTV-D Product Information Adobe Acrobat PDF page.

DTV - ATTC Releases Results of Lab Tests of Multipath Performance of DTV Receivers (Oct.)
The Advanced Television Technology Center (ATTC) has posted the results of its testing of eight consumer ATSC DTV receivers supplied by the Consumer Electronics Manufacturers Association. The results were originally presented in a paper delivered at the IEEE Broadcast Technology Symposium in Washington DC in September.
Because of the interest in DTV receiver performance in the presence of multipath, the ATTC added some new tests to evaluate how well the receiver equalizer performed. The new tests included: Susceptibility to random noise in the presence of short-static multipath, Susceptibility to random noise in the presence of short-dyname multipath and an additional test to determine the equalizer delay time range: Dynamic equalizer ghost cancellation. The testing found that the "the median receiver in these tests had consistently lower performance than the performance of the original Grand Alliance receiver." They did find, however, that two of the individual receivers "showed significant improvement in the present of short dynamic echoes."

The ATTC said that while these tests are "not intended to represent either actual reception conditions or a specification for receiver design, they do indicate that the performance of DTV receiver can be improved behond the GA reciever." "...the results of these test also point to an important need for further performance improvements beyond what is currently available in DTV receivers."
The DTV Peceiver Performance Study is available as an Adobe Acrobat PDF file. A copy of the presentation at the 49th annual Broadcast Symposium of the IEEE Broadcast Technology Society, DTV Receiver Performance Studies by Stanley Salamon, is also on-line, in Adobe Acrobat format.

DTV - CEMA Says DTV Sales "Explode" In September (Oct. 14)
The Consumer Electronic Manufacturers Association (CEMA) said DTV sales in September were more than double August sales. Year-to-date DTV sales were 53,415 units. CEMA said more than 15,000 DTV units were sold in September. CEMA President Gary Shapiro commented, "DTV is clearly here. The transition is fully underway. These figures reinforce what we have long believed: consumers who experience DTV love it and the excitement and interest in DTV is driving consumers into retail outlets, helping fuel extraordinary growth across the entire video category."

DVD sales also increased, with nearly 2.4 million DVD units shipped so far this year. The CEMA Press Release did not indicate if the number quoted for DTV units was limited to sets with ATSC tuners or if it included digital satellite receivers and DTV monitors without tuners as well.

DTV - Strategy Analytics Report Says FCC DTV Conversion Plan On Verge of Collapse (Oct. 15)
Strategy Analytics released a report that said "The FCC's plan to convert US households to digital television by 2006 is on the verge of collapsing." David Mercer, Senior Analyst with Strategy Analytics, said "Analog broadcasting is an anachronism in today's digital world, but it also fulfils a public service role. Switching off NTSC will be a far greater challenge than most people realize."

The report, "Interactive and Digital TV: Issues in the Transition Phase", was presented at the IBC Interactive and Digital Television Conference in Washington, D.C. Subscribers to Strategy Analytics services can purchase the report, which outlines different conversion scenarios and reconmmends a "Universal Broadband" strategy. The analysts concluded that terrestrial broadcasting will continue to lose share to other forms of distribution -- cable, satellite and, eventually, high-speed Internet.

Strategy Analytics has issued reports in the past that criticized government DTV transition policies. In November, 1998, David Mercer released a report "Selling off the Airwaves: Strategies for the Transition to Digital Broadcasting", that, according to the outline, said "cable and satellite distrubtion are currently better suited to supporting a competitive broadcast television market than terrestrial" and also stated "analogue terrestrial television broadcasting cannot easily be replaced".

Summaries of these reports are available from the Strategy Analytics home page. Enter the full name of the report in the search box on the home page to find the link to the summary. Information on purchasing the reports is also available on the site.

FCC Issues Warning About Cell Phone Jammers (Oct. 12)
The use of cell phone is prohibited some locations, particularly hospitals and theaters. Restrictions alone aren't enough to make everyone turn off their phones, so some people have resorted to using cell phone jammers. As anyone familiar with the FCC Rules and the Communications Act knows, these jammers are illegal. The FCC Office of Engineering and Technology released a Public Notice (DA 99-2150) warned "the operation of transmitters designed to jam cellular communications is a violation of 47 USC 301, 302(b), and 333. The manufacture, importation, sale or offer for sale, including advertising, of such transmitters is a violation of 47 USC 302(b)." The Public Notice warned that "Fines for a first offense can range as high as $11,000 for each violation or imprisonment for up to one year." As usual, offending equipment can also be seized and forfeited to the U.S. Government. The FCC Public Notice emphasized these "regulations apply to all transmitters that are designed to cause interference to, or prevent the operation of, other radio communication systems."

TECHNOLOGY - Microwave Satellite Propulsion System Design Started With Kitchen Oven (Oct. 15)
Most RF engineers are familiar with the use of microwaves for communication. Their use to cook food is also well known. What isn't widely known is that microwave energy can be used in a satellite propulsion system. Penn State engineers have been working with satellite propulsion systems using microwaves. The first model was built using parts from a 1000 watt kitchen microwave oven. The latest thruster draws only 80 watts and puts out more thrust than any system in its class, according the the Penn State News article New Mini Microwave Thruster Is Most Powerful In Its Class. The thruster is only 2 inches long and 1.25 inches in diameter.

Dr. Michael Micci, professor of aerospace engineering at Penn State and leader of both the original and current thruster projects outlined the benefit of the thruster. "Many commercial communications satellites in orbit today, for example, were still operational when they ran out of maneuvering propellant. The increased capacity of the mini-thruster could extend satellite life by three times the number of years."

The microwaves themselves do not provide the propulsion. Instead, they create and maintain a free-floating plasma within a cavity. When a cold propellant gas is passed through the hot plasma, it is heated and creates thrust when it is allowed to flow out through a nozzle. The plasma creates temperatures greater than those possible using chemical combustion, generating more thrust with the same amount of propellant gas. Safety is increased because the thruster can be turned off simply by shutting off the magnetron generating the microwaves.

For information on the original kitchen microwave thruster, see Kitchen Microwave Inspires Prototype Space Propulsion System from August, 1996.

OTHER Items of Interest

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Last modified October 24, 1999 by Doug Lung dlung@transmitter.com
Copyright 1999 H. Douglas Lung