Posts Tagged ‘Yagi’

Reading Between The Lines

In a report released yesterday, the Consumer Electronics Association states that 10% of American households are either ‘very likely’ or ‘likely’ to cancel pay TV services this year, while an additional 14% are either ‘somewhat likely’ or ‘somewhat unlikely’ to cut the cord. 76% of those surveyed were in the ‘unlikely’ or ‘very unlikely’ group.

While those numbers should give some pay TV operators a little cause for concern – maybe as an incentive to offer simpler, basic channel packages at lower costs – the CEA report then veered off in another direction.

The report, which you can read here, states that only 8% of all U.S. households rely exclusively on over-the-air (OTA) TV reception, a number that was immediately disputed by the national Association of Broadcasters, according to a story in Multichannel News.

The MCN story quoted CEA president and CEO Gary Shapiro as saying, “Contrary to the National Association of Broadcasters’ assertions, antenna sales are falling and cord-cutters are not shifting to over-the-air television but rather to the Internet. The only cord being cut these days is the one to the antenna.”

NAB’s spokesman Dennis Wharton was quick to respond. “CEA has zero credibility when it comes to calculating over-the-air TV viewership. Knowledge Networks has stated that over-the-air exclusive homes are more than 14% and rising. We trust an unbiased research firm over a survey paid for by CEA,” he replied.

Both my own experience and national news stories about cord-cutting have clearly shown that free, over-the-air TV is a key component of the cord-cutting experience. Why? Because it’s doggone difficult to watch sports and prime time TV shows in HDTV over a typical Internet connection, that’s why! And of course, OTA TV is free to viewers. So it is often combined with broadband access as part of the kiss-off to Comcast or Time Warner.

As it turns out, CEA has an obvious bias here. (Wow – this has been a bad week for objective research!) In a press release that came out earlier today, CEA announced that its Innovation Movement and Small Business Council would bring a ‘small business message’ to Capitol Hill.

The message? That small businesses “…run a gauntlet of new laws, new regulations and new costs that can put them out of business. Instead of imposing additional burdens, policymakers should be creating small businesses to invest, expand and create additional jobs.”

So where’s the bias? In the fifth paragraph of the press release, CEA states:

“Online, CEA’s Innovation Movement will be hosting a Virtual Lobby Day for its 114,000-plus members to encourage them to act on one key issue affecting small businesses: incentive spectrum auctions. CEA Innovation Movement members will be called to ask their congressional representatives to authorize the FCC to move forward with “incentive auctions,” which would provide broadcasters the ability to repurpose their frequencies through a spectrum auction in exchange for proceeds from auction revenues. Broadcasters could participate on a voluntary basis and purchasers could redeploy the spectrum for wireless broadband that could generate $33 billion for the U.S. Treasury and would allow endless opportunities for innovation in small business. “

A-HA! Apparently the primary motivation of this Innovation Movement is to pressure congress into selling off more broadcast TV spectrum. How, exactly, does that benefit a so-called ‘small business’ like mine? Seems to me such auctions would be far more useful Verizon and AT&T more than anyone else, and they’re as far removed from ‘small businesses’ as you can get.

According to Shapiro, “Using huge swaths of wireless spectrum to deliver TV to homes no longer makes economic sense. Congress should pass legislation to allow for incentive auctions so free market dynamics can find the best purposes for underused broadcast spectrum, such as wireless broadband.”

OK, connect the dots with me: (1) CEA’s members want more spectrum for broadband and other WiFi gadgets. (2) They think terrestrial broadcasters are vulnerable now. (3) So, CEA commissions a study that shows only while a small number of people are dropping or planning to drop pay TV service, these cord-cutters are NOT moving to over-the-air reception. No, they are instead turning to Internet-delivered video services. (4) Therefore, the country needs more bandwidth for broadband delivery of (among other things) video content, and less bandwidth for broadcast TV programs.

And I thought the recent Digital Entertainment Group survey of 3D TV trends was self-serving!  While I have no issue with the small number of cord-cutters the CEA identified, I simply cannot believe these ‘cutters’ would turn away from free HDTV programming for their new LCD and plasma TVs.

The CEA’s bias is clear now. In the last decade, they fought the digital TV tuner mandate, calling it an undue burden on TV manufacturers. Once the DTV transition got rolling, however, CEA did a flip-flop and showered praise on the FCC’s decision to move to a digital TV future, bringing free HDTV to millions of American homes.

Now, CEA has flipped again and says that free OTA TV is a dinosaur, and should be consigned to the dustbin of history in favor of wireless broadband in the UHF television band (a concept that is still on shaky ground technically).

I’m surprised the folks at CEA haven’t gotten whiplash from constantly reversing their positions. But it’s pretty clear now who’s really behind the curtains, calling the shots for CEA and also putting pressure on the FCC these days.

The question is; how many Americans still care that they can watch free HDTV anymore?

I’ll bet it’s a lot more than 8% of all U.S. households…

Can You Cut the Cord and Still Find Happiness in TV Land?

The newspapers have been full lately of stories that (a) claim cord-cutting will have no impact on pay TV viewing, or (b) show an increasing number of TV viewers are dumping (or strongly considering dumping) cable TV packages in favor of broadband video, or broadband plus over-the-air digital TV.

On the “it’s no big deal side,” you’ll find ESPN and Frank Magid Associates, while the “cord cutting is a growing trend” camp is represented by Parks and Associates, Time Warner, and SNL Kagan. While both sides acknowledge that the pay TV industry suffered its first-ever net loss of subscribers from April to September of this year, they disagree on the reasons.

ESPN and Magid claim that the total subscriber churn is less than 1%, and may be as low as one-quarter of one percent. They attribute the drop-off to the recession and expiring triple-play special deals. Parks points to the explosion in sales of Internet-connected TVs (NeTVs) and connected Blu-ray players and DVRs. Time Warner, in the meantime, just launched a lower-price basic “popular demand” channel package to hold on to subscribers, and will be followed by Charter Communications shortly.

Time for some clarity! According to a story on paidContent.org, Needham & Co. analyst Laura Martin reported the results of a simple request she made of 300 respondents in October: “Please list which TV channels you must have available online in order for you to turn off your pay TV subscription.”

Guess who sat at the top of the list? CBS, named by 35% of respondents. The #2 slot was filled by ABC (right behind at 34%), while Fox was in a tie with NBC at 31%.

The highest-rated pay TV network was (no surprise) ESPN, listed by 27% of respondents. The rest of the top ten was made up of Discovery (19%), History Channel (14%), HBO (11%), Comedy Central (10%), and The Food Network (also 10%).

It’s interesting that the top four networks are also available in many markets for free as over-the-air digital TV broadcasts. That also may explain why some cord-cutters are quick to dump cable TV and get their TV fix with antennas and a broadband connection.  (For what it’s worth, PBS finished in a seven-way tie with The CW, MTV, HGTV, CNN, Lifetime, and Bravo.)

The paidContent article comments that most respondents who voted for at least one over-the-air TV network also listed the rest of them. “Most folks think of the four broadcasters as a monolith,” said Martin. “This may be because consumers actually watch shows on all four broadcast networks, or it could be because they have no idea which network their favorite shows are on.”

For viewers who live near major cities, it’s not unusual to have as many as 30+ minor channels of free, over-the-air programming available. Those viewers are also more likely to have fast broadband, so cutting off cable or satellite TV still leaves them with plenty of program choices…and apparently, their ‘can’t live without’ TV networks as well.

So yes, you can find some happiness in the world of free TV…so long as you are willing to part with a few cable and satellite networks, and have a good broadband connection for Hulu, Netflix, YouTube, and other Internet TV channels.

To Readers: How about you? Would you be willing to drop cable or satellite TV, and just live with what you can watch using an antenna and a fast Internet connection? Or maybe you’ve already cut the cord? I’d like to hear your comments one way or the other.

How to Watch FOX 5 and My 9 Without Cable (updated)

Attention, Cablevision (and Time-Warner, and Comcast customers): The dispute with FOX 5 may be over, but it could happen again with another cable TV system – or another TV network. Here’s how to future-proof your TV reception against another retransmission rights dispute.

There are other ways to receive WNYW (FOX 5) and WWOR (My 9). Read on. One of them may work for you, and if so, you can continue to enjoy football and baseball while Fox and Cablevision “punt” this rights dispute back and forth to each other.

Here’s what you need to know: WNYW broadcasts a digital TV signal on physical UHF TV channel 44, even though the station identifies itself as “5-1.” And WWOR (My 9) broadcasts its DTV signal on physical UHF channel 38, even though it identifies as “9-1.”

So that means at the least that you need a UHF TV antenna. They’re not very large and they’re not expensive, either.

IF YOU OWN A NEW FLATSCREEN TV (VINTAGE 2007 – PRESENT)

All TVs manufactured after March 1, 2007 must include a digital TV tuner by law. So your new TV is already equipped to pick up WNYW. If you live within 10 miles of the Empire State Building, all you will need is a simple UHF antenna.

Radio Shack’s model T#749, catalog # 15-1874, is an excellent choice to start. It does not require any power, and if it doesn’t work, you can return it for a full refund within 30 days.  The cost is $12. Radio Shack’s Web site says this model is available in most stores.

(1) Connect this antenna to the “ANT IN” or “RF” threaded jack on the back of your TV. The loop portion is what is used to pick up WNYW, along with other UHF DTV channels like WCBS, WNBC, and WWOR (My 9). (If you want to pick up other VHF channels like WABC-7, WPIX-11, and WNET-13, extend the rabbit ears all the way, too.)

(2) Switch to the TV input. Next, consult your TV’s owner manual to find the menu selection for “Channel Scan” or “Scan for Channels.” Enter this menu, and make sure that “Air,” “Broadcast,” or “OTA” is selected and not “Cable” when you start a channel scan.

(3) Your TV will take about 2 – 3 minutes to scan for any over-the-air digital TV channels it can find. You should see a list of those channels as the scan progresses. If you see “WNYW 5-1” pop up, you are in luck! If not, reposition the antenna and try another scan. HINT: Elevate the antenna and place it near any open windows if you do not pick up the signal.

(4) WNYW also carries the WWOR My 9 programs as channel 5-2. And WWOR simulcasts WNYW FOX 5 programs on 9-2. So if channel 5 doesn’t come in after several tries, you may still be able to watch FOX programming on channel 9-2. Check that either or both channels were scanned and saved to memory.

IF YOU DON’T HAVE A NEW TV

Radio Shack continues to sell DTV converter boxes, even though the analog TV shut-down happened a year ago. Check your store for model DTX9950, catalog #: 15-150 (Digital Stream). It sells for $60. This converter box can be easily connected to your older TV set, using the RF or AV cables supplied with the converter.

(1) After connecting to your older TV, follow the converter boxes’ instructions on how to connect an antenna and scan for channels. The Radio Shack 15-1874 antenna works very well with this converter box, too.

(2) Again, look to see that WNYW 5-1, WWOR 9-1, or both channels have been scanned and saved to memory. You will be all set to watch the Jets game, NFC football, and the World Series. It will NOT be in high-definition, though.

IF YOU LIVE 10 – 15 MILES FROM EMPIRE

You may need an amplified antenna. The Radio Shack model 15-254, catalog 15-254 may do the trick. It costs about $35 and you can rotate the loop antenna for best reception. Radio Shack’s Web site says this model is available in most stores.

IF YOU LIVE 15 MILES OR MORE FROM EMPIRE

If you are more than 15 miles from the Empire State Building, a rooftop or attic antenna for UHF may be required. These are available at Home Depot, Lowe’s, and Radio Shack.

The Radio Shack model U-75R, catalog 15-2160 is an excellent choice. It costs $40 and is small enough to place in an attic, by a window, on a deck, etc. Just unfold the antenna elements, hook up the coaxial cable to your digital TV or converter box, and aim it in the direction of the Empire State Building. Scan for channels on your digital TV or converter box as before.

Good luck! Also reference these articles about indoor and outdoor DTV reception:

http://www.hdtvexpert.com/?p=449

http://www.hdtvexpert.com/?p=36

The DTV Transition: One Year Later

Many HDTVexpert.com readers know I started this Web site back in 2004 as a way to provide useful information on HDTV – how to receive it, how to watch it, and how to get the most out of it.

As it turned out, the most popular articles were (and continue to be) “how to receive digital TV” tutorials. More specifically; how to select and use antennas for over-the-air DTV reception.

Over this past Memorial Day weekend, I had a chance to visit the site of one of my more interesting DTV reception challenges. The house, located high in a steep valley in southern Vermont, is completely blocked-in by a ring of hills and sits 50+ miles from the Albany, NY TV transmitters atop Helderberg Mountain. (Well, most of ‘em are up there.)

The occasion was to install a new flat screen TV and tap my ground-level UHF/VHF antenna system one more time to provide free HDTV to that screen. (The other two taps drive Zenith converter boxes.)

Sure enough, after a few hours of stringing cable and drilling holes, my brother and his wife were able to watch the French Open in HD via NBC affiliate WNYT and the Indianapolis 500 in HD from ABC affiliate WTEN. I also tossed in an upscaling DVD player so that they could enjoy their sizable collection of DVDs in widescreen ‘near’ 1080p quality.

That RF system is done – there’s nothing I can do to improve it, other than periodic maintenance and repairs. And other DTV antenna systems I’ve installed in upstate New York, on a Canadian island, in Maine, at the Jersey shore, and on the roofs of a few locals are perking along happily, with their owners enjoying one of the few great deals left in this world…free television, and in high-definition, too.

It’s a work of art, and a thing of beauty.

My own system is doing a bang-up job hauling in DTV signals from New York City (65 miles), Scranton (70 miles), Philadelphia (22 miles) and Allentown (25 miles). If I get tired of all the ‘hometown cheering’ for the Phillies and Flyers on local DTV stations, I can always switch back to New York DTVs WCBS, WNBC, WABC, and WWOR and get the scoop on the Yankees, Giants, and Knicks. (And if WMCN-DT wasn’t spewing out their inane infomercials on channel 44, I could watch WTXF as well!)

The future of over-the-air DTV isn’t very clear at the moment. FCC Chairman Julius Genachowski has called for re-allocating much of the UHF TV spectrum, to be used instead for wireless broadband to solve an Internet ‘connectivity crisis.’ (Verizon chairman Ivan Seidenberg has gone on record as saying that this ‘crisis’ is largely non-existent, and that Verizon isn’t even using all of the recycled TV spectrum it bought for such an application.)

Even so, we might as well enjoy OTA DTV while it lasts, which I hope will be a long time. So that brings me to the point of this essay, which is to ask readers this: How is the DTV transition working out for you? Are you connected? Everything running hunky-dory?

Or, are you still having problems with antennas, or older set-top boxes? Still trying to pull in DTV signals in a tough location? Got noise or co-channel interference issues?

Tell me about them. I’d like to hear your stories, and will publish as many as I can.Maybe I can even solve a reception problem for you, if I get lucky.

Drop me an email at pete@hdtvexpert.com with particulars (and photos as well, if you have them). I’d like to get a sense of how many readers are still watching free over-the-air DTV. And how many have opted to drop cable, or cut back on it in favor of broadband video services like Netflix or Hulu.

It’s a very different world we’re living in than ten years ago. Back then, we got excited when a temporary antenna, braced out on our decks or stuck in a low-hanging tree, intermittently pulled in HD broadcasts of Monday Night Football. Remember how revved up you felt back then when the signal finally locked up?

Somehow, Peter Griffin and Saturday Night Live streaming to my laptop doesn’t hold quite the same thrill…

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.