Posts Tagged ‘DTV’

3D: All revved up, but nowhere to go!

How much fun would it be to buy a new sports car if there wasn’t any gas available to power it, or roads to drive it on?

That’s exactly the situation that today’s consumers are facing with 3D TVs: There just isn’t enough content to watch on them. And it’s even more of a problem with 3D movies, as manufacturers have inked several deals giving them exclusive rights to bundle specific 3D movie releases with their 3D TVs and Blu-ray players.

Remember when HDTV first got off the ground, back in 1998? There wasn’t a whole lot of HD content to watch, aside from a few prime time shows on CBS and the occasional movie on ABC.

Consequently, retail demand for HDTVs didn’t really take off until HD programming picked up with movies on HBO, an expanded slate of shows and sports on major TV networks, and the introduction of HD program services by Dish Network. The 2000 Super Bowl, the first to be broadcast in HD, helped generate more interest in HDTV sets.

Even so, it took a few more years before the ball really got rolling and events such as the 2004 Olympics, the Stanley Cup, NBA Playoffs, and World Series were all broadcast in HD formats.

While it’s true that 3D programming choices will expand considerably this month as ESPN launches its World Cup 3D coverage and DirecTV begins 24/7 3D broadcasts, the pickings are slim when it comes to 3D movies.

Those exclusive ‘bundling’ deals are part of the reason. Samsung has locked up 3D Blu-ray distribution of the Shrek franchise (four movies in all) for the rest of 2010, and had a recent exclusive deal for 3D BD copies of Monsters vs. Aliens.

Panasonic has a similar deal to ship 3D BD copies of Coraline and Ice Age: Dawn of the Dinosaurs in 3D with their 3D TVs, and apparently will have first dibs on Avatar when it’s released in 3D this fall, according to the Web site www.hollywoodinhighdef.com.

What’s more, Sony is apparently negotiating a deal with Disney to have exclusive rights to the 3D BD release of Alice in Wonderland this fall, bundling it with Sony 3D Bravia TVs and BD players. Cloudy with a Chance of Meatballs is supposed to be the first ‘open’ 3D BD release later this month, but even it will be part of a Sony 3D TV bundle (no surprise there, Cloudy was released by Sony Pictures!).

They jury’s still out on whether 3D in the home will be a success. But limiting the pipeline of 3D movies to a trickle at this critical juncture simply isn’t good business. If TV manufacturers really wanted to drive sales, they should pick up the costs of 3D BD mastering for popular movies and let distributors flood the market with these movies.

Frankly, I’m surprised the Blu-ray Marketing Association and Digital Entertainment Group aren’t lobbying more vigorously for this approach. The Blu-ray format hasn’t exactly been an overwhelming success, and 3D is a way for it to ‘niche’ its way forward as the replacement for red laser DVDs. (Incorporating DVRs and BD-R capacity into BD players is another, equally important way to drive adoption of the BD format.)

The DVD format wasn’t hamstrung like this, when it launched in 1997. Players were expensive at the time, but within months, consumers had plenty of DVD movies to choose from at retail, and it didn’t take long for rental stores to start offering them, either.

Reverting back to my analogy: For now, consumers can enjoy their shiny new sports car while it sits in the garage, or zips around the neighborhood. But until those fast roads get built and there is an ample supply of fuel, consumers will continue to drive around in their older sedans and SUVs.

Supply drives demand these days in the HDTV business. Come on, Hollywood – when will the floodgates open on 3D Blu-ray movies?

Aside to Netflix: What’s YOUR timetable for 3D movie streaming? Hmmm?

NAB 2010: A Show in Transition

Some of the big questions facing attendees as their flights landed in Las Vegas were these: Can NAB survive? Will it evolve into something different? Is it even that important to attend NAB anymore?

The answer to all three questions is “yes.” Even though attendance was still down from 2008 (NAB claimed 83,000 ‘officially;’ my guesstimate was more like 55,000 to 60,000), there were plenty of companies in attendance with lots of cool products to check out.

That said, the show is undergoing a rapid transformation away from a traditional ‘broadcasting’ show to a mix of InfoComm and CES – hot new products for professionals. Of course, 3D was all over the place. But so was networked video, which dominated the upper and lower South Hall exhibit areas.

Booths were smaller this year, and that’s not going to change any time soon…not when the typical booth is showing products that have price tags in the hundreds and low thousands. Contrast that with NAB shows 15 years ago, when most of the price tags had three and four zeros in them!

You know attendance was off when this was one of the largest booths in the Central Hall!

On the other hand, the alternative wasn’t too attractive…

The smaller booths and lower number of exhibitors resulted in wider aisles and less traffic – a plus. But it also resulted in NAB placing the main registration area smack in the middle of the Central Hall, something I’ve never seen before.  And there was plenty of wide-open space at the end of that hall, as well in the North and South Halls.

Can NAB be staged in three halls? Absolutely! And can you see everything you need to see in three days? Try two days. (Thursday has become ‘exhibitor bonding day,’ to quote a fellow editor.) I could have covered my beat in two days if necessary.

THE TRENDS

Not surprisingly, 3D was a big topic this year, although not to the same extent as it was at CES. The SMPTE/ETC/EBU Digital Cinema Summit focused entirely on 3D for both days, and I was fortunate enough to deliver one of the papers to a jammed room of 500+ attendees.

Sony, Panasonic, JVC, Canon, Grass Valley, AVID, Doremi, Harris, Evertz, and Ross Video were just some of the companies showing 3D products in Vegas. Those products ranged from 3D monitors and cameras to 3D workflow (acquisition, editing, post, effects, and playout) software and hardware.

Sony’s LM4251TD 42-inch LCD monitor uses micropolarizers for passive 3D viewing.

Other specialized 3D brands were in attendance, too. TD Vision, Miracube, Mistika, and HDlogix had nice exhibits in the South Hall, down the street from Grass Valley. Smaller companies like Cine-tal occupied the 3D Pavilion nearby, while Motorola and Ericsson showcased 3D transport and format recognition products upstairs.

Although the consumer TV market is seeing a big push towards active-shutter 3D TVs and monitors, the emphasis at NAB was on passive 3D viewing (cheaper glasses, more expensive displays). JVC, Hyundai, and LG all manufacture them, and there were plenty of folks standing around with RealD X-pol eyewear watching the demos.

The projector guys were on top of things, too. projectiondesign showed a stacked pair of 3-chip 1080p lightboxes in the Mistika booth, using linear polarized glasses. HDI showed a 100-inch, 1080p LCoS rear-projection TV in the HDlogix booth, also using X-pol glasses. Christie also had suitable 3D projection systems out for inspection.

There were also some demos that left me scratching my head, such as Canon’s dual-projection X-pol 3D demo, using a pair of REALiS WUXGA (1920×1200) LCoS projectors. While it worked well, it requires two separate projectors and outboard 3D filter holders – too klunky! (A Canon rep told me that was because of the 60 Hz frame rate limitation on the internal video processor.)

Well, it IS 3D, but I doubt Canon will sell very many of these rigs…

Broadband video and IPTV were also big this year. This market for MPEG-4 AVC over Ethernet, fiber, or private data networks is exploding, and encoder companies such as Adtec, Vbrick, Harmonic, Ericsson, Harris, Motorola, and Digital Rapids were showing a full range of compatible products.

Sezmi also occupied a booth at the show. This company has a unique selling proposition – a set-top box that receives both terrestrial (read: free) digital TV and selected cable channels carried on secondary terrestrial channels. It also accesses a video-on-demand server through broadband connections (SDTV only) and has a customizable program guide for each user.

While not technically broadband, the nascent MH broadcast format was in abundance at NAB. MH uses MPEG-4 AVC coding in multiple streams with IP headers to send low-resolution video to handheld receivers, such as mobile phones and combo PDA/receiver products. MH is catching on in popularity with broadcasters, who see it as a more sensible alternative to simple multicasting of secondary channels that very few people may be watching.

ATSC MH on an iPhone? Brilliant! (There’s an app for everything!)

MY PICKS

After three days of walking around, I came up with a list of “finds” that I’ll share here. These are all products that represented clever thinking, breakthrough technology, and/or new price points. Some were easy to spot; others required quite a bit of digging. But they all made the trip to Lost Wages worth it (and that’s saying a lot, considering how airlines jam you in like sardines these days!).

TV Logic: This manufacturer of LCD broadcast monitor showed the world’s first active-matrix OLED broadcast monitor (unless you think Sony’s press announcement hit first, which it didn’t.) The LM-150 ($6,200) uses a LG Display 15-inch OLED panel with 1366×768 pixel resolution and come equipped with all the expected niceties including markers, crop marks, caption displays, over/underscan, and HD/SDI, HDMI, and analog video jacks. There’s also a 3D version in the works (TDM-150) that will sell for about $7,700.

This was the coolest product at the show. But will it REALLY last 30,000 hours?

Ericsson: In addition to a host of MPEG-4 and IPTV encoders, the ‘big E’ also showcased an innovative, iPad-like LCD touchscreen remote control/video viewer. Dubbed the IPTV remote, this product can dial up video from broadband, cable, satellite, and even your home network. Not only that, it can monitor weather sensors and your home security system. (Sound much like a Crestron product?) The IPTV remote will not be offered for sale at retail. Rather, it’s intended to be a content provider offering.

Christie: Have you seen their MicroTiles yet on the Colbert Report? These innovative ‘mini’ DLP projection cubes use LED light engines to power 800×600 DMDs (the actual working resolution is 720×540) and measure about 12” x 16.” They can be configured in just about any format you wish, including floor and ceiling projection, and up to 1024 can be driven at one time. The LED light source is specified to last over 60,000 hours. Think of LED-powered LEGOÔ blocks, and you’ve got the concept.

And YOU thought iPads were all the rage…

SmallHD: It wasn’t easy finding these guys behind the Sony booth, but they’d come up with a focus assist monitor for video and still cameras that they claim is the world’s smallest HD video monitor. The actual size is about 5.6 inches and the glass is WXGA (1280×800) LCD. It comes in two flavors – one for digital SLRs ($899) and one with SDI input ($1199). The monitors are an inch thick, weigh 10 ounces, and mount to hot shoes.

Z3 Technology: I found this booth on my last pass through the South Hall, and it was worth the stop. They showed the Z3-MVE-01 MPEG encoder, a compact box that codes HD up to 1920×1080 resolution using H.64 High Profile (up to 30Hz), with Ethernet and ASI outputs. Input compatibility includes composite, component, HDMI, DVI, and HD-SDI video…all for $5,000.

JVC’s 46-inch X-pol monitor always drew a crowd.

Adtec: I didn’t expect to see an HDMI-to-QAM modulator at the show, but that’s exactly what Adtec pulled out for me. The HDMI2QAM is a dual-channel design that encodes anything from the HDMI inputs (yes, they are HDCP-compliant) to a pair of quadrature amplitude modulation (QAM) channels, using MPEG-2 encoding. The modulation format is selectable between 64-QAM (SD), 128-QAM (not widely use), and 256-QAM (HD). Bit rates are constant and optimized for each mode (i.e. 38.8 Mb/s for each HD channel).

 

Cydle: This new start-up demonstrated an app for iPods and iPhones that allows viewing of ATSC MH (A/153) video. Along with it comes the i30,  a battery-powered docking station with built-in antenna (UHF). This means that your ‘i-whatever’ has two batteries to draw from, so if you run low on talk power, simply switch to the i30 battery. Both can charge simultaneously. Cool!

Sezmi’s personal program guide rivals TiVo for user-friendliness.

Panasonic: I’ve seen it before at CES, but it now has a model number. The company’s first production camcorder now goes by the moniker AG-3DA1 and is yours for the low, low price of just $21,000. (Well, all things are relative, I guess.) The camera weighs about 6 and a half pounds and uses a pair of 2.l07 MP sensors (full 1920×1080) to record 1080i and 720p HD content to SD memory cards. Convergence and horizontal and vertical displacement are fully adjustable.

Panasonic gets another mention for the AG-AF100, which they claim is the world’s first Micro 4/3-inch (1.33:1) HD camcorder. That’s a big deal because the 4/3” format matches the coverage area of 35mm film frames…which means you can use standard 35mm film camera lenses to get effects like shallow focus, soft focus, and vignettes. The camera records to SD/SDHC/SDXC memory cards using the AVCHD format and supports 1080i/p and 720p formats, including 23.98/24/25 Hz.

Sony gets extra credit for announcing the world’s second (or first) AM-OLED professional video monitor. The PVM-750 ($3,850) is a bit smaller than TV Logic’s offering at 7.4 inches (16:9), and is not quite full HD resolution at 960×540 pixels. (Not that you’d notice on such  small screen!)  The PVM-750 has 3G HD-SDI, HDMI, and composite video inputs, the full range of adjustments from tally and markers to blue screen mode and AC/battery power operation. No word on lifespan of the display, but Sony uses small molecule (SM) OLED technology, as does LG Display.

LP Technologies rounds out my list with one of those ‘too good to be true’ products: An LCD-based 9 kHz to 3 GHz spectrum analyzer with USB 2.0 interface, built-in preamp, and Ethernet connectivity for remote monitoring. Sorry, no internal battery pack!) The USB hook-up can be used to save data in the Excel format, while the internal memory can tore 900 different waveforms. The display is a 6.4” 640×480 (VGA) LCD type. And the cost? Just $4,500…

Stick one of these on a Canon 5D MK II, and you can shoot an entire episode of ‘House!’ (No kidding!)

Product Review: Three For DTV…Reception (February 2009)

I recently had an opportunity to test indoor DTV reception at a potentially “tough” location in New York City. This particular apartment requires an indoor TV antenna and sits about 3.5 miles from the Empire State Building, alongside Central Park.

The apartment is on a lower floor and next to several tall buildings that contain lots of steel and glass in their outer structures. The challenge was to come up with a model that would provide reasonably strong signals with minimal multipath, looking through or positioned just below a couple of small windows that face west, looking out over the northern section of the park.

Seeing as how RCA had just sent me their ANT1450B amplified VHF/UHF panel antenna (MSRP: $49.95), this seemed like a perfect location to give it a test drive. For more fun, I also packed up Terk’s HDTVa VHF/UHF indoor antenna (MSRP: $59.95) and Radio Shack’s “bare bones” 15-1874 VHF/UHF indoor antenna (MSRP: $11.99), along with a spectrum analyzer to accurately see how each antenna was working.

For test receivers, I packed up the AutumnWave OnAir Solution HDTV-GT receiver (5th gen) and my Acer notebook PC, plus a new entrant to the set-top box field – Aurora Multimedia’s V-Tune Pro HD ATSC/NTSC/QAM/IPTV receiver (MSRP $1,299). This box has RS232 controls and supports both component video and HDMI outputs – plus, it’s LAN-ready for streaming video and updating software and hardware.

THE LOCATION

The test apartment is currently undergoing interior re-decorating, so I simply placed each antenna near one of the two small living room windows and peaked it for best analog TV reception on as many channels as possible. The quality of each channel varied considerably, as you can imagine – multipath was so bad on some channels that it was difficult to get any reliable NTSC signals.

I then did channel scans with both the V-Tune Pro HD and the HDTV-GT, to see how many signals locked up both receivers. MPEG stream analysis was also done with the HDTV-GT and TSReader Pro, so I could check modulation errors. The results were surprising, to say the least.

The active DTV stations I was trying to receive included WNYE-24, WNBC-28, WPXN-30, WPIX-33, WNJU-36, WWOR-38, WXTV-40, WNYW-44, WABC-45, WNJM-51, WCBS-56, and WNET-61. Some of these stations have very strong signals, and I can pick ‘em up at home, 65 miles away in eastern Pennsylvania. Others aren’t quite as loud.

Figures 1a-b. Radio Shack’s 15-1874 “budget” VHF/UHF indoor antenna in a formal pose (top) and in action (bottom).

RADIO SHACK 15-1874

This antenna is about as simple as it gets. It consists of a small plastic base with a metal bottom, a thin-wire UHF loop that snaps into place, and a pair of thread-on, telescoping VHF rabbit ears. The 15-1874 is the kind of antenna many folks might use with NTIA DTV converter boxes, to replace their old, broken rabbit ears.

After peaking for best analog reception, I did a channel scan and was able to pull in 7 of 13 stations currently broadcasting digital TV signals from the Empire State Building, 4 Times Square, or other locations. For what it’s worth, two of the stations that didn’t make the grade (WNJU-36 and WNJM-51) currently broadcast from towers in New Jersey, and were just too weak to be picked up even though I spotted ‘em on the analyzer.

Figure 2a. Qualcomm’s MediaFLO service on UHF channel 55 (left waveform) and WCBS-DT on channel 56 (right waveform), as received by the 15-1874.

Figure 2b. DTV waveforms from WNYW-44 (left) and WABC-45 (right), as grabbed by the Radio Shack antenna. Note the strong tilt on WABC’s signal.

Figure 2c. WWOR’s digital signal on channel 38 was problematic, and that big notch in the middle of the 8VSB waveform was the reason – it kept fluctuating up and down.

Of the remaining stations, one (WNET-61) is operating with very low power and is beaming its signal west towards Newark, NJ – its city of license. I could see it on the analyzer, but it was just too weak to pull in. (WNET will go back to VHF channel 13 after the analog shutdown, and should be plenty strong in the metro NY area, based on tests conducted in early January.)

The other two stations (WPXN-30 and WWOR-38) just had tricky multipath that the RS-1874 couldn’t do anything about. After all, it’s basically a dipole antenna on UHF with little directivity. I don’t expect the rabbit ears to make that much difference with high-band VHF channels, either. Still, for $12, this antenna did a fine job and is a low-cost solution for city dwellers that live 10 or fewer miles from the transmitter site(s).

Figure 3a-b. RCA’s ANT1450B in a beauty shot (top) and on the front line (bottom).

RCA ANT1450B

I’d tested the non-amplified version of this antenna (ANT1500) back in the late summer, and found it wanting for indoor reception at my location. The ANT1450B also uses a similar etched strip-line VHF/UHF antenna design, but included an in-line amplifier module to boost overall signals levels.

Given that my home location is 23 miles and over a hill to the Philadelphia antenna farm, I figured the New York location would be a kinder test of the RCA’s abilities. Once again, I positioned it near one of the windows and peaked it for best NTSC reception, and then did a channel scan.

Figure 4a. WCBS’ digital signal on channel 56 was a real challenge for the ANT1450B.

Figure 4b. WNYW-44 (left) and WABC-45 (right) looked a bit better through the RCA antenna.

Figure 4c. WNYE-24 had a booming signal at the reception location.

The results? Without the companion amplifier, the ANT1450B pulled in 6 of the 13 available DTV stations, once again skipping WNET-61. It also missed WPXN-30, WNJU-36, WWOR-38, WFUT-53, and WCBS-56. This antenna is just as non-directional as the 15-1874, and equally susceptible to multipath. With re-positioning, I was able to pull in WCBS-56, but dropped WABC-45 and WPIX-33.

Adding the amplifier accomplished two things. First, I was now able to add WFUT-53 and WCBS-56 to my original list, although the latter channel showed “hits” now and then. Second (and unfortunately), the noise floor on VHF channels 7 through 13 was elevated by 20 dB! That’s not a good development, and one that spells trouble for WABC, WPIX, and WNET when they go back to their original high-band VHF channels 7, 11, and 13, respectively.

Figure 5a-b. Terk’s HDTVa antenna looks aerodynamic just sitting still (top) and like it’s ready for takeoff when in use (bottom).

TERK HDTVa

This antenna continues to impress me, although its UHF section isn’t much of a mystery – it’s the Antiference Silver Sensor, coupled to an internal amplifier. The VHF element is a bit more pedestrian, with a pair of telescoping rabbit ears. They are robustly built, though.

After waiting for the usual channel scan, I discovered both the Aurora and OnAir receivers had logged 12 of 13 DTV stations (nope, still no sign of WNET-61). More importantly, only two (WPIX-33 and WPXN-30) showed any signs of “hits” from time to time. Impressively, I could now watch WNJU-36 and WNJM-51, previously missing in action.

Figure 6a. WWOR-38 came in beautifully through the HDTVa.

Figure 6b. WNBC-28’s 8VSB waveform, although ragged, was rock-steady with the Terk.

Figure 6c. WNYW-44 and WABC-45 looked best with the HDTVa.

Although the HDTVa is vastly more directional than either the Radio Shack or RCA designs, its performance could be even better if it had a reflector behind its rear element. WPIX’ channel 33 waveform showed some pretty funky notches, and WPXN could have used a bit more signal overall. I also noticed hits on other channels that seemed to be tied to the passage of busses and trucks in the street below, but these primarily affected upper UHF channels (53, 56) that won’t be in use after June 12.

As well as the HDTVa performed, it also raised the high-band VHF noise floor by 20 dB or so, indicating the presence of some type of broadband RF emitter nearby. Perhaps that was a computer, or a security system sensor. (I’ve even seen high-band VHF RF emissions from a hand-held HD camcorder, believe it or not!)

Figure 7a. Here’s what the normal nose floor looked like underneath VHF channels 7, 9, 11, and 13.

Figure 7b. And here’s what the RCA and Terk amplifiers did to it – raise it up by 20 dB!

Figure 8. Aurora Multimedia’s V-Tune Pro HD did a creditable job pulling in the test DTV signals.

CONCLUSIONS

My tests at this site aren’t yet complete, and another round of testing will include antennas with improved directivity to help minimize multipath. But if I had to go with one of the test antennas, I’d pick the Terk HDTVa. It did the best overall job on UHF DTV and analog VHF signals, and the internal amplifier (although not a low-noise design) does make a difference – plus, it works a lot better than the in-line amp module RCA ships with their ANT1450B.

I was very impressed at how well the RS 15-1874 worked, but given its traditional design, a lot of the credit must go to the OnAir HDTV-GT and Aurora’s V-Tune Pro. Stand-along HDTV set-top boxes are getting harder to find these days, and one that’s integrator-ready like the V-Tune Pro are rare. It works very well, and its receiver is even a bit better with tricky signals than the Gen 5 HDTV, now two years old.

As for RCA’s ANT1450B, it would appear to work best in a location where it has a clear shot towards a transmitting antenna. Handling multipath is not its strong suit, but what can you expect from what amounts to a pair of folded loop antennas, mounted inside of each other’s radius? I’d skip the in-line amplifier unless you live in a less congested area – too much garbage gets pulled in and winds up degrading the noise figure of the receiver.

Radio Shack 15-1874

Budget VHF/UHF Indoor Antenna

MSRP: $11.99

http://tinyurl.com/2ml5re

 

RCA ANT1450B

Amplified VHF/UHF Indoor Antenna

MSRP: $49.95

http://tinyurl.com/b7ksnr

 

Terk HDTVa

Amplified VHF/UHF Indoor Antenna

MSRP: $59.95

http://tinyurl.com/arntk

HDTV Tech Talk: I’ve Got The Low-Band DTV Blues (June 2009)

One of the more interesting stories that has developed following D-Day (June 12) is the trouble that viewers are having in several large markets with low-band TV channels – specifically, channel 6, which is now digital in Albany, NY; Philadelphia, PA, New Haven, CT, and five other TV markets.

There have also been reports of difficulty with stations on channel 7, most notably WLS in Chicago and WABC in New York City. The situation there is quite different, but we’ll take a quick look at it at the end of this article.

THE OP-ED SECTION

First off, let it be said that the FCC’s decision to retain channels 2 through 6 in the DTV channel core was ill advised. These are some of the oldest TV channels in existence and used to be the prime spots for a TV station, since they were the lowest channel numbers on tuners.

But the frequencies in which these channels are located – specifically, from 55 MHz to about 88 MHz, give or take several kilohertz – have long been plagued with impulse noise, such as you’d get from noisy fluorescent lamp ballast, brush motors, or any electronic equipment that creates inductive voltage spikes.

To make matters worse, seasonal signal propagation enhancement, caused by sporadic ionization of the ionosphere’s E-layer, can cause signals on these frequencies to hop across the country and create co-channel interference many thousands of miles away. Ham radio operators like myself refer to this summertime phenomenon as “E-skip,” for short.

Here’s another reason why channels 2 through 6 should have been retired: They require very large antennas for efficient reception. A full-wave loop antenna for channel 2 (56 MHz) would measure 5.4 meters in length, or about 17.5 feet! (Contrast that with a full-wave loop for UHF channel 42, which would be about 18 inches around.)

This makes it problematic to design an indoor antenna with any kind of gain, short of adding an internal amplifier. Unless that amplifier’s design is bullet-proof (and for normal Radio Shack prices, it usually isn’t), the antenna system will be overwhelmed with noise and interference from other nearby RF signals, such as FM radio stations.

THE CHANNEL SIX CONUNDRUM

But that’s water under the bridge now, and 40 stations have decided to stay put on this not-so-valuable real estate. As a result, I’m getting quite a few emails about some bizarre low-band VHF reception issues.

My favorite so far is from a television station monitoring service, whose rooftop channel 5 antenna in West Virginia is being routinely wiped out every day by fluorescent lights in the Ace Hardware below, during normal store hours. (Not impossible to fix, but it will take some detective work.)

Getting back to my home market of Philadelphia, there are plenty of problems with reception of WPVI’s digital signal on channel 6. And it became evident pretty quickly that WPVI was having these problems just 24 hours after shutting down their analog signal on channel 6.

Subsequently, WPVI and CBS affiliate WRGB in Schenectady, NY (also on channel 6, and also experiencing reception issues) applied to the FCC for an emergency authorization to go to higher power.

According to  a news story in the June 22 issue of Broadcasting and Cable magazine, “…The FCC granted the station (WPVI) a special temporary authority (STA) to boost its transmission power on Ch. 6 from the relatively low 7.5 kilowatts (kW) to 30.6 kW, the maximum power for the northeastern “Zone 1” region of the U.S.”

Figure 1. WPVI’s DTV signal on VHF channel 6, seen at 1:00 PM on June 12. Each of the sharp, rounded signals to its immediate right are FM radio stations.

WPVI’s original digital signal on June 12 at 1 PM, as seen in Figure 1, wasn’t too shabby to begin with, and I could receive it quite easily on both my rooftop and attic antenna systems. It also came in nicely near the southwest wall of my house, on both floors, while using Eviant’s T7 Card portable digital TV set.

But there are always devils in the details, and you can see them quite clearly immediately to the right of WPVI’s flat-topped 8VSB carrier. Those numerous rounded peaks are FM broadcast stations, the closest of which is on 88.5 MHz (WXPN). Almost immediately adjacent is WRTI’s FM operation on 90.1, followed by WHYY on 90.9, etc.

So, what’s the problem? Those FM stations are co-located at the Roxborough TV tower farm, NW of Center City. And they present very strong signals that can slip through the filters in NITA converter boxes, resulting in interference to the channel 6 signal. What’s more, FM and TV signals mixing in converter box receivers will produce sum and difference frequencies that wind up right in a portion of the channel 6 spectrum.

So what’s likely happening is that closer-in TV viewers, who probably don’t have really long rabbit ears (a full-wave loop @ 85 MHz measures 3.53 meters, or 11.6 feet) are trying to pull in a signal that’s competing with strong, adjacent-channel signals from FM  broadcasters. Toss in the usual elevated noise floor from arc lamps, power transformers, air conditioning compressors, and refrigerator motors, and you have a sticky wicket indeed!

Figure 2. WPVI’s “boosted” DTV signal, as seen at 9:45 AM on June 22. It’s about 6 dB stronger than before.

Figure 3. This wide view of the TV spectrum from channel 2 to channel 13 shows how strong WPVI’s new signal is, compared to WBPH-9 and WHYY-12 (far right).

WPVI’s Special Temporary Authorization (STA) from the FCC definitely resulted in a stronger signal, as seen in Figure 2. And Figure 3, which shows a wider view of all low-band and high-band VHF channels, plus the FM band, reveals that WPVI’s broadcast is now the strongest TV signal coming out of Philadelphia. (Notice the comparatively weaker signal from WHYY-12, the 8VSB carrier to the far right.) But is WPVI even strong enough now?

In both of my spectrum analyzer screen grabs, you may notice that the FM radio station carriers get progressively weaker as the frequency increases. That’s because I’m using an FM trap to try and attenuate them. But that filter simply isn’t sharp enough to subdue WXPN, WRTY, and WHYY without also affecting the strength of WPVI’s signal.

Only precision signal filters with multiple poles and what we call “Hi-Q” sharp filter skirts can solve this problem. Except that filters like that are VERY expensive to manufacture, and not something you’d put into a $59 converter box or a $500 TV set.

The adjacent channel overload problem is compounded by the use of circular signal polarization from FM stations. This is done among other reasons so that their broadcast signals remain moderately stable in as your drive around in your car. But that’s no help to the home TV viewer, who may try to no avail to weaken the FM signals by positioning their TV antenna horizontally or vertically.

Figure 4. A spectral view of WRGB-6 in Schenectady, NY, also “up against it” with multiple strong FM stations in close proximity.

In case you think this is just a “big city” problem, look at Figure 4, which shows the FM carrier immediately upstream from WRGB-6 in Schenectady. Same problem – multiple strong FM stations that can play havoc with converter boxes and integrated TV sets are located immediately adjacent to WRGB’s 8VSB carrier. And similar complaints about lost reception are coming into the chief engineer’s office up there.

OK, SO WHAT DO WE DO NOW?

Unfortunately, there isn’t any “one size fits all” fix to this problem. But there are some things that may work.

Inline signal attenuators: First of all, ATSC signals will come through at very low carrier-to-noise ratios, where analog NTSC signals won’t. It stands to reason that viewers close to the TV antenna farms have more than enough signal to begin with, so the counter-intuitive approach is to add attenuators inline with the antenna leads.

This will result in a weaker signal on channel 6, but will also drag down the levels of FM stations, too. Toss in an inexpensive FM notch filter, and at some point the TV receiver or converter box may be able to make better sense of the differences between the FM and channel 6 8VSB signals.

Of course, for this to work correctly, the attenuator should only be in the VHF antenna line, because it’s also going to clip signals from every TV station upstream from the filter, including high-band VHF and UHF. The VHF antenna should also be horizontally polarized, and not vertically polarized. That means flattening out those rabbit ears, or using a bar antenna or folded dipole on the roof, or in the attic.

Eliminating noise: Another possible problem is broadband noise, as I mentioned earlier. It’s worth checking out DTV reception problems with as many of your home appliances and lights disconnected as possible, to see if some “hash” isn’t getting into your system and creating interference problems.

Such interference would manifest itself on the FM band (Surprise! FM isn’t completely noise-free) as well. Any offending appliances should be replaced or repaired, because they’re likely creating bigger interference problems with other electronic devices in and nearby your home.

Using the wrong antenna: Of course, in more than a few cases, the problem seems to be one of trying to receive VHF channel 6 with a UHF antenna, which of course is akin to trolling for marlin with a Pocket Fisherman.

Many folks don’t realize that WPVI is now relocated a long ways away from its former position on UHF channel 64 (about 771 MHz), and that the small UHF loop antenna that used to work so well to pick up Jim Gardner and Action News is little more than a piece of decorative aluminum when it comes to watching VHF TV channels.

So what’s needed is a pair of longer rabbit ears, or even better yet, a folded dipole antenna that can be mounted on the side of a house, or in the attic – or even on the roof. The size would be ½ the length of a full-wave loop, or about 5 feet 9 inches. (5 feet is close enough for government work.)

This folded loop can be made out of copper tape, aluminum, or stiff wire – anything conductive. Even refrigerator drain hose (also copper) also works. Simply solder the leads of a 300-ohm coaxial balun to the open ends of the loop and run a piece of RG-6 to it, and you’re in business. Here’s a link to a simple folded dipole design, made from TV ribbon wire (twin lead). It’s scalable to any VHF channel.

Of course, you can also try a pair of conventional rabbit ears, but if you’re close in to the TV station (10 miles or less), stay away from amplified designs. They’ll only make the problem worse. On the other hand, WRGB’s chief engineer reported at least one viewer had complained about losing the signal on his rabbit ears antenna…30+ miles away. In that case, the amplifier is a good idea, but a rooftop or attic antenna is a lot more sensible.

MEANWHILE, BACK AT THE RANCH…

The problems that have been reported with reception of VHF channel 7 in New York City and Chicago appear to be arising from either improper antenna selection, or elevated noise floors, a common problem in cities. VHF signals have a tough time penetrating tall buildings, a task that UHF signal seem to handle with more aplomb.

But once again, a UHF antenna is not even close to resonance at 180 MHz (Channel 7). That’s about 1.67 meters, or 5.5 feet for a full-wave loop antenna. The good news is, everyday rabbit ears will usually do the trick here, but you’ll need to experiment with their polarization to see what works best. Fortunately, there aren’t any pesky FM radio station carriers lurking nearby.

What there IS, however, is lots of broadband noise. Figure 5 shows a spectral view of analog channels 7 through 13 in New York City, about 3.5 miles northeast of the Empire State Building, inside a 3rd-floor apartment where I’ve been researching an indoor TV antenna design.

Figure 5. Here’s a view of the TV spectrum from channel 7 through 13, as seen from the upper reaches of Fifth Avenue in New York City.

Figure 6. Whoops! Adding a preamplifier didn’t make matters better; it made them worse by elevating the noise floor.

So far, so good! But I wanted a little bit more separation between TV carriers and noise for more reliable DTV reception and to feed multiple TVs. So, I tested an inline preamplifier – with disastrous results. Figure 6 shows that the amplifier boosted channels 7 through 13 by almost 20 dB, but also kicked up the noise floor by the same amount – basically accomplishing nothing.

Lesson learned? I’ll have to come up with most of the gain in the antenna system, and try with different combinations of attenuators and preamps to see how I can add some “active” gain to the system without adding more noise and creating a new set of headaches.

I’ll be conducting more tests on channel 6 reception and also high-band VHF stations during the summer to see what practical solutions myself and others can come up with. Look for more coverage of this issue later in the summer. In the meantime, email any questions and observations you may have about “difficult” DTV stations, so we can share them with other readers.

WABC, Cablevision Kiss and Make Up. Who’s Next?

Disney-owned TV station WABC made good on its threat early Sunday morning to pull its signal from Cablevision systems in New York and northern New Jersey after a dispute over retransmission fees could not be resolved amicably. But the two companies reached an agreement about 15 minutes into the Oscars telecast, restoring the signal just as the nominees for Best Supporting Actor were announced.

According to several published news reports, WABC was seeking a fee of $1 per subscriber, whereas Cablevision was countering with 25 cents per sub. Supposedly, the companies arrived at a figure in the range of 60 cents per sub, although that can’t be confirmed right now.

In a similar battle last December, the Fox network duked it out with Time-Warner, asking for $1 per sub but reportedly getting about half that in the final negotiations. It’s expected that Disney (the owner of ABC and ESPN) will play even harder ball against Time Warner in August, when those cable carriage agreements come up for renewal.

The timing couldn’t be worse for Cablevision subscribers, what with the Academy Awards telecast on Sunday. But it didn’t mean all was lost – it just meant folks would have to try and pull in the signal on channel 7 using an old-fashioned antenna.

WABC’s signal is quite strong down here in Bucks County, PA and I can receive it with a five-element VHF yagi plus a mast-mounted preamplifier, mounted about five feet above my roof . The straight-line path from here to the Empire State Building is about 65 miles, and there are two ranges of hills in the way.

Here's my rooftop antenna system, aimed at New York City. The lower antenna does a great job pulling in WABC-7.

So I’d expect almost anyone who is 30 miles or less from Empire with a reasonably clear path will be able to pull in WABC’s HD signal, using an outside antenna. Within 15 miles, you may only need an indoor antenna, preferably one that can be rotated and has a switchable amplifier built-in.

Get used to these retransmission fee disputes – you’re going to hear more about them with each passing year, as TV stations move away from the old “must carry” system – where a local station had to be carried on the cable system, but received no money for that carriage – to retransmission agreements, which place a value of the TV station’s content.

Traditional TV networks are realizing their programs are worth just as much (if not more) than that offered by cable nets like USA, TBS, and TNT. And with advertising revenue down, thanks to the recession, those per-subscriber fees are becoming vitally important.