RF Technology: Doug Lung

Doug Lung is vice president of engineering for the Telemundo Group of stations. Contact him via e-mail at dlung@transmitter.com

Juggling Antennas for 2009 Requires Planning
The last FCC "use-it-or-lose-it" deadline has passed and most stations with a tentative DTV channel designation on their existing DTV channel, have constructed their fully maximized facilities.

NAB RF Reflections: A-VSB and DTx
At NAB this year, walking around booths displaying products on video-over-IP and video to handheld devices, it was easy to forget that some people still watch TV from high-power transmitters.

What to Expect at NAB2006 for RF
NAB2006 this year should be interesting as manufacturers deal with an anticipated drop in demand for high-power TV equipment after the last maximization deadline passes in July and stations wait for the announced end of analog TV transmission in February 2009.

Is Your Transmission Line Digital TV Ready?
When designing a new DTV transmission facility or planning DTV conversion of an existing analog facility, in addition to selecting a transmitter with sufficient power and an antenna that has the correct tradeoff between gain and elevation pattern, be sure to consider the transmission line.

FCC Proposes Rules For DTx
This month, I'll examine the FCC's rulemaking on DTx released Nov. 4; two papers presented at the IEEE Broadcast Technology symposium in October; and results of tests on Samsung's new Gemini VSB chipset at CRC Canada.

How Hard is it To Receive DTV? Part II
Last month, I looked at the technical arguments in the debate over how to determine whether a household can receive a local network affiliate's DTV signal and thus is not allowed to receive a distant network DTV signal via satellite. This month, I'll finish the discussion with more details on the debate and reply comments from Meintel, Sgrignoli and Wallace (MSW) on behalf of NAB.

So Just How Hard Is it To Receive DTV?
Earlier this summer, an interesting debate developed around the FCC Notice of Inquiry on "Technical Standards for Satellite-Delivered Network Signals" over how to determine whether a household can receive a local network affiliate's DTV signal over-the-air.

Broadcasting To Cell Phones
This month, I'll focus on technology that will deliver over-the-air TV to consumers, but that won't use broadcast TV transmitters in the United States.

Check Your DTV Signal With These Low-Cost Tools
This month, I'll provide a more detailed look at Rod Hewitt's TSReader program.

Elevating Accuracy in Longley-Rice Coverage
Using the most accurate data possible when designing a new broadcast facility reduces the chances of real-world coverage problems.

NAB Spotlights RF T&M Gear for DTV
As I've written before, I felt there was a great need for easy-to-use equipment for monitoring 8-VSB transmissions and ATSC streams. There was no shortage of DTV and 8-VSB test equipment at NAB this year. Prices were low enough. There is now no excuse for not knowing exactly what your station is transmitting on DTV.

Channel Election Choices Revealed
Let's take a more detailed look at the channel elections on a band-by-band basis.

Going to Digital ENG: 30 Months and Counting
All 2-GHz broadcast equipment will be upgraded to digital technology and will be operating under a new band plan that keeps the same number of channels but reduces their width to 12 MHz.

Do-it-Yourself Longley-Rice Studies
Many readers have asked how they can generate terrain-sensitive coverage maps like the ones I've used in my columns.

IEEE II: Receive Antennas & Unlicensed Devices
This month, I continue my coverage of papers at the IEEE 2004 Broadcast Technology Symposium with a look at a paper by Kerry Cozad outlining receive antenna measurements, and William Meintel's evaluation of the FCC Notice of Proposed Rulemaking (NPRM) to allow unlicensed devices in vacant TV channels.

DTV Transition Discussed At IEEE BTS 2004
Last month, I reviewed a petition by Hammett and Edison for reconsideration of the FCC's Second DTV Periodic Review Report and Order.

Coverage Complicates Channel Elections
This month, I'll examine the options stations have in the channel election process.

Transmitter Options for Digital Televsion
Now that the FCC has set deadlines for maximizing or replicating coverage, many stations will be looking at upgrading DTV transmitters or in some cases even replacing them.

DTV Antenna Coverage Illustrated
This month, I'll outline some factors to consider when designing a DTV antenna.

Choosing a Final DTV Channel
This month, I'll look at some of the things to consider when deciding on a DTV channel, and also relay some information I received from readers about low VHF DTV.

RF@NAB: DTV Reception And Interference
At NAB2004, broadcast engineers were focusing on getting ready for the shutdown of analog TV.

Low-Band VHF DTV Revisited
My March 10 column "DTV on Low-Band VHF Channels" generated a large amount of e-mail. Many of the comments described experiences receiving low-VHF analog and DTV stations (Channels 2-6) and a few others focused on the reasons low-VHF DTV reception is difficult. This month I'll share some of those comments with you and offer some ideas on why low-VHF DTV reception is such a challenge.

NAB 2004: RF Expectations
This month I'll outline what I expect to see at NAB and highlight some of the more interesting papers on the NAB Broadcast Engineering Conference schedule.

DTV On Low-Band VHF Channels
Last month I heard from a reader asking my opinion on whether they should keep their UHF DTV channel or go back to their low-VHF analog channel for digital at the end of the DTV transition when analog TV is shut off.

Broad Signals
Increasing frequency congestion has made it necessary for broadcasters to pay attention to the bandwidth and spurious signals from all their transmitters if they want to be good neighbors and avoid a citation from the FCC. Broad signals are not appreciated!

RF Reflections and Predictions
This month I'll look back to address comments received on my November RF Technology column and look forward to TV broadcast RF issues I believe will be important in 2004.

The 53rd Annual IEEE Broadcast Symposium
There are many fine technical conferences and broadcast shows in early Fall, but the one I always make it point to attend is the IEEE Broadcast Symposium, held in October in Washington D.C.

FCC Bulletin OET-69 Limitations
The FCC database used for FCC Bulletin OET-69 interference studies does not include TV stations' real antenna patterns.

Useful RF Help On the Net
When I started my RF Web site back in 1995, there were few with information on RF and TV broadcasting. Eight years later, almost any question about RF can be answered with a quick Google search.

Calculating RF Power Density and Exposure
The FCC is actively checking broadcast sites for compliance with FCC Rules §1.1310, RF radiation exposure limits.

RF at NAB2003: DTV Reception, Part 2
In my last column I discussed transmission technology at NAB2003. This month I'll wrap up NAB coverage with a look at DTV reception technology discussed at the convention.

RF Highlights at NAB2003
At this year's NAB, the focus was not on debates about DTV standards or the transition, but discussions on how to make DTV transmission and reception work and improve DTV broadcast equipment. Part I

Enhanced Propagation of TV Signals
Interference between DTV and analog stations sharing the same channel was back in the in the news this summer when WBOC in Salisbury, Md,. reported problems with interference from WHRO-DT in Hampton Roads, Va.

Rebuilding NYC TV Transmission After 9/11
This month I'll look at some of the challenges New York City broadcasters face restoring TV coverage to what existed Sept. 10, 2001. As promised last month, I also will outline some of the reasons DTV to analog (and vice versa) interference in some cases is likely to be greater than what was previously predicted.

Low-Power DTV at NAB
In my last column I looked at DTV reception technology at NAB2002. This month I'll look at the other end of the path -- DTV transmission, specifically low-power DTV transmission.

DTV Reception Advances At NAB2002
Consumers have gotten used to easy NTSC reception. If the picture looks bad, move the indoor antenna around a bit and you can usually get a watchable picture. Even if the picture is poor, if the program is interesting enough, the viewer will usually continue watching it if the audio holds up ... DTV is not as easy. Once reception is lost, it isn't always obvious how to get it back!

Receive Antennas Revisited
My March column on DTV receive antennas generated more e-mail than any column I've written in a long time. I'll share the responses and look at what a report from the ATSC had to say about DTV receive antennas.

(11.28.01)

Lessons Learned at IEEE
During the weeks following the attack on the World Trade Center I was busy assisting our local engineering staff in restoring the WNJU signal at the Armstrong Tower in Alpine, N.J.

Philips, NxtWave Describe Their Plans
In response to my July column I heard from many of you about the efforts that manufacturers are making under the ATSC 8-VSB improvement effort. Philips and NxtWave sent me additional background on their proposals, some of which I will talk about here.

2 Measuring and Extending DTV Coverage
Cable carriage of broadcast stations’ DTV signals is not mandated under current FCC rules as long as their analog station is carried.

1 8-VSB Enhancements – Will They Work?
Last year, at NAB2000, the hot topic among TV broadcast engineers was whether or not COFDM would be allowed to join 8-VSB as one of the authorized DTV modulation formats.

FCC Defines DTV ‘City Grade’ Contour
How do you define DTV coverage? Since 1997 the FCC has defined it as the 41 dBu F(50/90) contour for UHF stations, 36 dBu for Channels 7-13 and 28 dBu for Channels 2-6.

RF Ramblings – Anticipating NAB 2001
The annual NAB convention is the most visible forum in North America where engineers report on the achievements of the previous year and show what they hope to achieve in the following year.

Combining High Power TV Signals – Analog and Digital
There has been a lot of interest recently in combining multiple NTSC and DTV signals onto one antenna. The reasons for this are simple – tower real estate is expensive and, in some cases, existing towers aren’t going to be able to support additional DTV antennas.

8-VSB vs. COFDM: The Debate Continues
Over the last few months, me and many others have written about the relative merits of COFDM and 8-VSB for DTV. It is the most pressing issue facing broadcasters today.

Exotic Modulation – Beyond 8-VSB
There are currently some new, exotic modulation methods under development. Although these methods are not likely to be used for traditional broadcasting, the technology behind them is interesting and will affect broadcasting in one way or another in the years to come.

Antennas Garner Attention at IEEE Symposium
The IEEE Annual Broadcast Technical Symposium (IEEE-BTS), held this year in Tyson’s Corner, Va., is the best conference for learning about new broadcast RF technology.

Comparing 8-VSB and COFDM for DTV Broadcasting, Part II
After reading last month's column you may have concluded that the DVB-T COFDM transmission system had enough advantages over the ATSC 8-VSB system to justify using it to replace or supplement 8-VSB.

Comparing 8-VSB and COFDM for DTV Terrestrial Broadcasting, Part I
Several events are causing many broadcasters to wonder whether the ATSC 8-VSB modulation method was the best choice for U.S. digital television terrestrial broadcasting (DTTB).

Over Hill, Over Dale
Software for Predicting Coverage Maps and Plotting Microwave Path Comes of Age
Over the years, I've written about software that could be used for predicting coverage maps and plotting microwave paths. Until now, none of the inexpensive software maps had sufficient resolution to be used for plotting microwave paths.