Posts Tagged ‘VHF’

Classic Product Review: Eviant T7 Card Portable Digital TV (2009)

It’s finally over. The United States has transitioned away from analog (NTSC) TV broadcasting after 60+ years, and moved to an all-digital system (8VSB) for full-power TV stations. (Low power and translator stations are still analog for a few more years.)

The NTIA converter box program is slowly winding down, and the latest estimates from Nielsen (June 21) showed that about 2.1 million homes, or 1.8% of all over-the-air TV viewers, were still unable or unprepared to watch digital TV.

The upside? Over 62 million converter box coupons had been mailed as of June 24, with 32 million redeemed and 24 million expired. And of course, every new TV set that supports NTSC reception must also support the ATSC DTV standard. So, we’re out of the woods with DTV reception issues, right?

Not quite. Everyone that ever bought a portable TV, from Sony Watchman LCD sets to tiny tabletop CRTs, just saw their investment reduced to zero on June 12. None of these legacy sets can receive ATSC signals, and it’s impractical to connect an NTIA converter box as a “retro move,” since there’s only one model that can run off batteries.

Never fear; Eviant is here! The company recently introduced two new LCD portable TV sets that are fully ATSC-complaint. Both sets are being featured as “hurricane TVs,” or sets you should keep around in case of a weather emergency.  But they’re also good-looking and small enough to use for everyday viewing on the go.

The T7 “Card” is the larger of the two models and the one that’s currently shipping to retail. According to the press release, “…The Eviant “Card” series 7-inch digital portable TV is available now in leading retail outlets including Kohls, JC Penny, Walmart.com, Target.com, Belks, Aafes, Bon Ton, D&H, HSN, Amazon.com, Shopko, Marsan and more with a MSRP of $169.99.”

Figure 1. Eviant’s T7 “Card” portable digital TV, shown in a white finish.

OUT OF THE BOX

Eviant’s T7 is about the size of a thick paperback book, and not all that heavy. It measures 7.3 inches wide by 5.7 inches high and is 1.1 inches deep. With the included lithium ion battery, it tips the scales at just over a half-pound. The supplied lithium ion battery charges up quickly (less than one hour), and is supposed to provide 2.5 hours of viewing time between charges.

Eviant has shown this TV with different color finishes. The official press photo shows a white housing, but my review sample was black and I also saw a red version at the CES summer line show. The shipping box shows pink, blue, and green as additional “skin” options, so you can knock yourself out with color coordination options!

The T7 isn’t just a TV. Eviant has also included a composite video input and mini audio connection to go along with it, plus a matching cable. If you have a portable media player with these connections, you can at least watch your videos on a larger screen. There’s also a mini-stereo headphone connection for private listening.

The whip antenna is actually a slide-on whip, which means you can pull it off and hook up other types of antennas to the threaded F connector. (Bravo, Eviant!) Eviant’s also included a little vertical UHF antenna with a magnetic base that you can stick just about anywhere.

The TV has a swing-out support stand for tabletop use. There’s even a credit card-sized remote control that has extremely limited functionality — basically, you can adjust volume and channel, plus access the menu. There isn’t even a power button on the remote (strange!), but there is a “channel +10” button for moving around faster.

The LCD display measures 7” and has a working resolution of 480 x 234 pixels, so don’t go crazy expecting to see HDTV on this product. Remember — it’s a portable TV, first and foremost. Besides, trying to put a 7” HD display in a product like this would be overkill.

Figure 2. The T7 (and its “coming in the 3rd quarter” 4.3” companion) grabbed more than a few eyeballs at the CES NY Line Shows in early June.

MENUS AND OPERATION

Eviant has included a surprising detailed menu. There are five sections you can diddle around with — Picture, where you can select the AV input or regular TV mode, plus choose between Personal, Dynamic, Standard, and Soft image presets, and fine-tune contrast, brightness, and color.

The Audio menu is where you can adjust balance, plus select the preferred language when more than one audio track is available. The Clock menu lets you set the OSD duration in 15-second increments, plus toggle to your time zone and switch Daylight Savings Time on and off.

The Tools menu is where you can set the OSD transparency (on or off), color temperature (Warm, Normal, Cool), and the picture Zoom mode for when 4:3 content is displayed on the screen. The default (factory) setting for this control is Wide, but you can switch everything (including HD broadcasts) to 4:3. Or, you can just select Auto, and let the T7 provide the correct screen size, based on the video format being transmitted.

The last menu, Channel, is where you’ll scan for ATSC and NTSC channels. Believe it or not, the T7 will also scan for and receive NTSC and QAM digital cable channels (handy for when there’s a cable TV feed near your campsite, I guess?). The NTSC support means you’ll still be able to pick up local community TV stations, which converter boxes won’t receive.

You can initiate a general channel scan in this menu, and also an overlay scan to pick up any channels you may have missed the first time around. This secondary scan is also handy if you rotate antennas or travel, and don’t want to lose digital TV channels you captured previously.

PERFORMANCE

I first tested the T7 by connecting it to my attic antenna system, which feeds my home office. It takes a while to scan — about two and a half minutes to saunter through channels 2 through 69 — but once done, works as well as any PC-based digital TV tuner I’ve tested. As you step through channels, you’ll see a blue display in the upper right corner of the screen showing you each station’s virtual channel number and call sign.

One thing you won’t see on the T7 is PSIP. For whatever reason (and it may be that cost is the reason), there is no way to display electronic program guide information on the T7. It will, of course, display closed captions. But the only way you’ll know what you’re watching is to change the channel up and down to get the virtual channel display to appear briefly onscreen again.

The next step was to connect the T7 to my rooftop antenna via a splitter, with the other leg feeding a Zenith DTT901 DTV converter box. My goal here was to see how the two compared in terms of sensitivity and ability to handle multipath.

The answer? They were equivalent in performance on both close-in and distant DTV channels. I installed a 20 dB step attenuator in line to both sets and began cranking back signals 1 dB at a time until they started to break up or drop out. That point was exactly the same for every channel on both the T7 and the DTT901( the latter is effectively running Generation 6 8VSB receiver technology).

An inquiry to Eviant’s PR firm came back with the response that the receiver’s chipset is made by MStar Semiconductor of Taiwan, and is the MSD110. From my tests, it appeared functionally the equivalent of the LG 8VSB front end used in the DTT901.

The next test took place during my Super Tuesday session at InfoComm. The session, attended by 180+ people, was held in Room 303 of the Orlando Convention Center. I scanned for channels and picked up over 25 different NTSC and ATSC programs, most of which played just fine without any dropouts, no matter where I placed the TV in the room. (This location is over 20 miles distant from the Orlando TV transmitters.)

Figure 3. Yep, I was able to watch snippets of “Wipeout” on WABC-DT, while zipping along in a double-decker train through the Jersey Meadows!

Figure 3. Yep, I was able to watch snippets of “Wipeout” on WABC-DT, while zipping along in a double-decker train through the Jersey Meadows!

The final test was to take the T7 into New York City for some press meetings. One was uptown at the Hilton Times Square, and the others were at the Metropolitan Pavilion on 18th Street. Reception was perfect on 42nd Street by Times Square on all channels, including high-band VHF channels 7 (WABC), 11 (WPIX), and 13 (WNET). Reception deep in the Hilton was spotty in places, but still better than I expected.

Later on that afternoon, I plunked the T7 on the wooden bar of an Irish pub on 18th Street, as our group tossed down a quick round of Harp lagers before Pepcomm’s Digital Experience opened. Once again, I experienced flawless reception of all NYC DTV channels with the whip first extended halfway, and then fully extended. (The T7’s whip is actually more resonant at UHF frequencies when somewhat collapsed).

Just for laughs, I pulled the T7 out seconds after my westbound, double-decker NJ Transit Midtown Direct train exited the New Jersey side of the Hudson River tunnel. I flipped it on and was able to watch quite a bit of programming on WABC-7 and WPIX-11, even with the train moving at a pretty good clip — 50+ miles per hour. I could see the Empire State Building through the opposite train windows for a good part of the trip, so I figured it was worth a try.

Of course, signals were lost completely when we went through the Secaucus train station and also when we crossed lift bridges and went under other tracks. But the video and audio were there about 70% of the time. And once the train pulled to a complete stop in Newark to take on and pick up passengers, VHF and UHF DTV reception was rock steady.

CONCLUSION

Eviant’s T7 delivers the goods. It has an excellent DTV receiver front end and worked very well indoors in what are difficulty high-multipath environments (Times Square, 18th Street, and the Orlando Convention Center). Audio is surprisingly loud for such a small TV, although frequency response is limited. Images were very clear and crisp, even at low resolution.

What I didn’t like: Even with a +10 channel jump button, it takes a while to move from one channel to another. There should also be a power switch on the remote control. And I’d like to see at least a “mini program guide” button included, so you at least find out what the heck program you’re watching.

The time (broadcast by every digital TV station) isn’t even displayed, unless you go into the menu. Oops! That info would be very helpful on a “hurricane TV.” Oh, and by the way, Eviant — how about a car charger adapter for this TV, in case of a power failure that lasts more than 2.5 hours?

In any event, the T7’s faults aren’t deal breakers. From what I’ve been told, pricing is very competitive on this product — a quick check online shows Target pricing them at $149.95, and Amazon had the black version listed as low as $119. For that kind of money, you can’t go wrong.

SPECIFICATIONS

Eviant T7 Portable Digital TV
MSRP: $169.99

Specifications:
Dimensions: 7.3” W x 5.7” H x 1.1” D
Weight: .55 pounds*
RF Input: “F” connector with fitted collapsible whip
TV Systems: NTSC, ATSC, QAM
Video inputs: (1) Mini-plug
Audio inputs: (1) stereo mini-plug
Audio output: 8-ohm stereo mini plug
* Owner’s manual says .55 pounds, press release says 1.39 pounds

Available from:

Eviant
1661 Fairplex drive
La Verne, CA 91750

www.eviant.com
(866) 935-4396

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.

Classic Pete: Up On The Roof…Once Again

Three DTV antenna installations in two weeks — just another “day at the office?” Not for two of the homeowners involved, who are enjoying more free HDTV channels now.

It’s been a while since I got up on a roof with my tools and wired up an antenna system. With a whirlwind Panasonic dealer tour taking up most of my time in October (along with thousands of miles logged on United and US Airways), it was a nice break to put aside the computer and Powerpoint presentations, strap on my tool belt, and work with my hands.

As it turned out, I upgraded two systems and built a brand-new system for the third location. Off-the-shelf antennas and preamplifiers were used in each case, along with existing DTV sets and set-top boxes. Propagation tests and TVFool.com plots were used along with a Sencore SA1501 portable spectrum analyzer to align the antennas and verify reception at each location.

FIRST STOP: WALL TOWNSHIP, N.J.

I had previously set up this location a few years back to receive as many of the New York City DTV stations as I could. Back then, all of them were transmitting on UHF channels, but the combined antenna owned by CBS and mounted on the NW side of the Empire State Building still had pattern problems.

In particular, WNBC-28 was getting out horribly with a pattern that looked more like broken glass than a semi-circular shape. The pattern was so bad that I couldn’t even receive the station reliably when sitting on top of the Ramapo Mountains in NW New Jersey, looking directly at Empire with a Channel Master 4308 UHF yagi.

Following the analog shutdown on June 12, three NYC stations gave up their UHF assignments and moved back to highband VHF channels. WABC vacated channel 45 and returned to VHF-7, while WPIX turned UHF-33 over to WCBS and went back to VHF-11. WNET completed the trifecta by bailing out of UHF 61 (now out of the DTV core) and resuming transmissions on VHF-13.

Why didn’t WWOR move back to channel 9? Asleep at the switch, I’m afraid. WBPH in Allentown, who had been assigned UHF-60 originally, moved their operation to channel 9 and decided to stay put when the final channel elections were conducted. So, WWOR was forced to stay on UHF-38, carrying their own programs on minor channel #1 and duplicating WNYW’s telecast on minor channel #2. (The story behind that arrangement, along with WNYW simulcasting WWOR on 5-2, is best left for a future column.)


Figure 1. The “old” antenna setup (since June 2009) for VHF/UHF reception in Wall, NJ.

The original antenna setup (Figure 1) was a modified CM4308 driving a CM 7775 Titan 2 mast-mount preamp, fastened to a chimney atop a one-story house barricaded immediately to the north by tall trees. The location, just west of NJ Route 18, sits about 39 miles from Empire “as the photon flies” and was a good candidate for strong highband VHF reception, too.

The problem: The owner had originally replaced the CM4308 with a Channel Master 2016 and CM 7777 dual-band preamp at my suggestion to pull in 7, 11, and 13, but no luck. Channels 28 and 33 were solid, while WNYW-44 was in and out. Not good if you are a New York Giants fan and want to watch NFC games on Fox! Figure 2a shows the weak VHF signals on those channels using the original antenna setup, while figure 2b reveals that WNYW, while presenting with a clean waveform, has just barely enough carrier-to-noise to lock up reliably.

The fix: I ordered an Antennacraft Y5-7-13 five-element highband VHF yagi ($26.99 plus shipping) to replace the single angled half-wave dipole element on the CM2016, and set the internal combining switch on the CM 7777 preamp to separate VHF and UHF inputs. Out came the original CM4308 and it went atop a newer, taller mast (Figure 3).


Figure 2a. Highband VHF signals were weak through the CM2016.


Figure 2b. WNYW-44 was intermittent.

After careful aiming with the SA1501, it became apparent that, while the optimum heading for the VHF yagi was true to the TVFool prediction, the optimum heading for the CM4308 was about 5 degrees farther east to clean up the pattern from WNYW-44.

Figure 4a shows the improvements to channels 7, 11, and 13, adding NJ Public TV station WNJB-8 to the mix, while figure 4b shows UHF channels 25 through 40 all booming in. A stronger, dropout-free 8VSB waveform from WNYW-44 is seen in Figure 4c. (That’s WNJT-43 off the side of the antenna.)

Now, the homeowner has reliable reception of all major network channels, even in high winds (which we experienced that day) using a DirecTV set-top receiver with ATSC tuner. That means was able to see the NY Giants get their butts kicked on successive weekends by the Cardinals and Eagles! (Be careful what you wish for…)

Note that, as of this writing, Channel Master has discontinued the CM4308 from its catalog. Not to worry! You can use a CM2016 in its place — just don’t connect the single dipole VHF element, although you should fold it out into its normal position.


Figure 3. The new split-stack UHF/VHF array, showing the offset for UHF reception.


Figure 4a-b-c. Now, channels 7 through 13 are solid (left), while UHF stations are slightly stronger (center) and WNYW-44 has lots more headroom (right).

SECOND STOP: HOME SWEET HOME

Not many people come home from church services at noontime on a sunny, warm day and say, “Gee, I think I’ll go up on the roof and change out my antenna system!” But I’m a bit strange that way. My wife asked me if she should stick around to help out while I was up there, but I assured her I was perfectly capable of falling off a roof by myself with no additional help. (Black humor…)

Turns out, I ordered two of the Antennacraft Y5-7-13s, which (for some strange reason) they insist on shipping FedEx Green with signature required. Apparently, theft of TV antennas from front porches is a problem in some parts of the country?

Last December, I had replaced my old setup with a pair of CM 2016s, stacked and offset on a rotatable mast. The offset was designed so that when the bottom antenna was aimed towards Philadelphia, the top antenna was aimed towards New York City (60+ miles away, over two ranges of hills).

The problem: As things turned out, I rarely need to move the Philly antenna, but I did rotate the top CM2016 frequently to pick up stations as far away as Scranton/Wilkes-Barre (70+ miles, also over two ridges). Alas, after 6/12/09, I lost WABC, WPIX, and WNET completely as they moved back to the VHF band. As I discovered at the previous location, the CM2016s weren’t up to the job of pulling in these stations, even though they did snag WBRE-11 and WYOU-13 from Scranton — pretty impressive for a single half-wave dipole!

Figure 5. My lower, fixed CM2016, aimed permanently towards the Roxborough (Philadelphia) antenna farm.

Figure 6. The new UHF/VHF stack, aimed towards New York. Told you it was a beautiful day for antenna work!

The fix: This was a three-art solution. First, I removed the lower CM2016 and fastened it to the rotor support, permanently aimed SSW towards Roxborough, about 22 miles away as seen in figure 5. It feeds the combined input of a CM 7777 preamp, necessary because I split the signal several times to distribute it through the house.

Next, I re-installed another CM4308 atop the mast and Y5-7-13 below it, both feeding another CM 7777 preamp in split-input mode. This array would become my “DX” antenna (figure 6), although I anticipated leaving it aimed towards New York most of the time.

Results were encouraging, although not perfect. Figure 7a shows the RF spectrum from channels 7 through 13 before the upgrade, while figure 7b shows the same channels afterwards. Not a substantial difference to be sure, except that the antenna is now more selective and I gained some C/N headroom on channel 7. WPIX-11 and WNET-13 are largely unchanged, which would imply that I had some enhanced propagation when I took the original measurements back in late June of 2009.

Reception of all three VHF channels continues to be problematic, although each has gotten much stronger. Channels 11 and 13 in Scranton are no doubt causing co-channel interference problems, so I may never get that resolved. As for WABC-7, I don’t think the station is running enough power for highband VHF operation — another 3 or even 6 dB would seem to be in order.

Figures 7a-b. Channels 7 through 13 as received on the old CM2016 (left) and the new Y5-7-13 (right).

Figure 8. There’s lots of RF coming in from New York on the low UHF band!

On UHF, signals just barrel in, as seen in figure 8. WNBC-28, WCBS-33, WWOR-38, and WXTV-40 are all strong, 24/7. Unfortunately, WNYW-44 can’t get through because of co-channel interference from WMCN-44 in south Jersey (no NY Giants NFC games…sigh…), while WPXN-31 just isn’t strong enough to peek through.

Supposedly, an upgrade to the combined VHF antenna atop Empire is in the works for 2010, according to sources in the industry. Maybe that will change things for the better!

LAST STOP: SAUGERTIES, N.Y.

My last trip was up to the foothills of the Catskills on a rainy, foggy early morning. My goal? Install VHF and UHF antennas for reception of Albany and Schenectady DTV stations, allowing the homeowner (my youngest brother) to “cut the cord” and drop expensive cable TV channel packages while retaining broadband service from Time Warner.

The problem: This location, on the side of a hill and about 35 miles from the Helderberg Mountain antenna farms over a 1-edge path, didn’t look to be particularly difficult. (Figure 9) I had run some UHF DTV reception tests at this location a few years back with encouraging results. At the time, most of the Albany DTV stations were on UHF, with a couple plugging away on highband VHF. Post-transition, I’d need to pull in WRGB-6, WXXA-7, WNYT-12, WNYA-13, WTEN-26, WMHT-34, and WCWN-43 at the least.

Figure 9. The Saugerties location had a nice, nearly flat roof to work on.

Figure 10. Here’s the final UHF/VHF stack with the CS600 on the bottom.

The fix: Because the Albany market has a lowband VHF DTV operation (WRGB-6), I ordered Antennacraft’s CS600 dual-band yagi ($34.72 + shipping), the same antenna that is currently sitting about a foot off the ground at the “fringe” SW Vermont location I wrote about this past August.

UHF reception would be taken care of by yet another CM 4308, sitting a few feet above the CS600 on the stack. (Figure 10) A quick test with my spectrum analyzer showed that it didn’t much matter where I mounted the antenna on the roof — I’d have plenty of signal to work with, except from WNYA-13. This channel exhibited low signal levels no matter where I spotted the mast.

(Subsequent email chats with one Albany DTV engineer revealed that the WNYA-13 DTV antenna system does not get out as well as other stations and is side-mounted on the old WRGB analog channel 6 tower — PP)

Each antenna drove the separate inputs of a CM 7777 mast-mounted preamp (gotta love it!), which in turn was scheduled to go into an existing eight-way splitter from the original cable TV distribution system. As it turned out, only four of the taps on the splitter actually led to any TVs or wall-mounted jacks, so I swapped it out for a more reasonable four-way split arrangement.

Figure 11a-b-c. WRGB-6 is super strong (left), while WXXA-7 (center) and WNYT-12 and WNYA-13 (right) are sufficiently powered up.

Figures 12a-b-c. WTEN-26 (left) is another monster signal out of Albany, while WMHT-34 (center) and WCWN-43 (right) are “merely” strong enough!

Figure 11a shows the unbelievably strong signal from WRGB-6, boosted shortly after 6/12 to overcome possible interference from those adjacent FM broadcast stations and also to fill in holes in signal coverage. Figure 11b shows WXXA-7; while figure 11c lets you clearly see the power disadvantage of WNYA-13 (right) compared to WNYT-12 (left).

As for UHF, you can see the strong signal from WTEN-26 in figure 12a (that’s WTBY-27 to its right, many miles SE of my location), with WMHT-34 and WCWN-43 visible in figures 12b and 12c, respectively. WYPX (ION) from Amsterdam just wasn’t strong enough to lock up on either of the Digital Stream DTV converter boxes I installed in the house — too far away.

Oddly enough, WNYA-13 will only come through on two of the three active RF feeds in the house, even though a test of signal levels showed all three to be about the same. Switching converter boxes out didn’t make any difference, so there may be a problem in one of the coaxial lines I’ll have to ring out on a future visit. In the meantime, the system was up and running in time for us to watch Game 3 of the World Series…even if it was downconverted digital TV of an old Philips CRT set.

Tech notes: Antennacraft yagis are designed with square booms and cannot use conventional round boom hardware that is common to Channel Master yagis. You will get a hardware bag with the antenna — don’t lose it! Also, you will need to purchase a balun transformer separately to make your coaxial feed, as Antennacraft doesn’t provide baluns or weatherproof boots with their yagis.

Figure 13. Here’s one way to attach a round balun to a square boom. (Sounds like one of those mental puzzles from my childhood…)

Figure 13 shows a Channel Master balun attached to a Y5-7-13 and secured with tape. It’s a good idea to form the balanced wire connections into drip loops and mount the balun underneath the antenna. Also, add a drip loop to the coax feed before it attaches to and travels down the mast.

Classic Pete: Once More, Out To The DTV Fringe

Recently, I made a third trip to my brother’s house in the hills of southwestern Vermont to finish what I started over two years ago – set up this distant, remote location to receive every digital TV channel from Albany. And I succeeded.

 

 

My first visit in May of 2007, chronicled here, showed that a modest suburban UHF yagi (Channel Master’s model 4308) and a low-noise preamp was sufficient to pull in four Albany DTV stations over a 54-mile path by taking advantage of knife-edge refraction of the RF signals, bending over a range of hills about ½ mile to the southwest of the house.

I was surprised at how strong the “bent” signals were, even with moderate multipath distortion. But they came in just fine on a pair of Gen5 ATSC DTV receivers, with minor interruptions in service during periods of heavy rain or dense fog.

Still, I hadn’t resolved the issue of receiving a pair of high-band Albany VHF DTV channels – WXXA-7 (Fox) and WNYT-12 (NBC). That would be addressed during my next visit in early January of this year, and you can read about it here. Trust me; it wasn’t much fun working outside in sub-zero temperatures. And I didn’t have the best antenna for the job, relying on a used Terk TV35 suburban VHF/UHF yagi to pull in the signals, aided by a dual-band, low noise preamplifier.

I knew a third and final tweak to the system would inevitably be in order, particularly to improve the reception of WXXA-DT. Plus, WRGB-DT (CBS), previously operating on UHF channel 39, was scheduled to move back to VHF channel 6 on June 12 as the analog TV shutdown was completed. And another Albany DTV station, WNYA (MyTV), hadn’t even signed on yet- they were still waiting for WNYT to vacate their analog signal from channel 13.

 

 

THE FINAL PUZZLE PIECE

The first order of business was to replace the Terk TV35 with a more serious VHF yagi. Fred Lass, chief engineer at WRGB, kindly sent along a pair of Antennacraft Y5-2-6 low-band VHF yagis for the job, but those wouldn’t help me with channels 7, 12, and 13.

Instead, I opted for the Antennacraft CS600 VHF yagi, which would provide reception from channel 2 through 13 and which (according to the specs) was good for up to 40 miles on low-band VHF and 50 miles on high-band VHF. Coupled to the Channel Master #7777 dual-band preamp, I figured it would be enough.

The next step was to check reception from the January installation by recording new spectrum analyzer plots and comparing them to the screen grabs I captured eight months ago. Good news – the 8VSB carriers from the remaining UHF stations (WTEN-26, WMHT-34, and WCWN-43) hadn’t changed any, even with all the nearby trees fully leafed out.

Unfortunately, signals from WXXA-7 and WNYT-12 didn’t look too good, thanks to a broken rear reflector element on the TV35. So, I removed the Terk from the system and assembled the CS600. I also had to install a second, offset antenna mast to clear the rear elements of the CS600 from the deck supports, not to mention a large rose bush which had grown around the mast and TV35!

 

 

 

 

 

To make everything fit in this tight space, I drilled a set of new boom-to-mast bracket holes near the rear of the CS600. The antenna is light and sturdy enough to be mounted this way, although I recommend using the standard mounting holes when up on a rooftop mast to balance the antenna and reduce wind load.

From my January escapades, I found that the TV35 worked better when it was offset about 30 degrees farther west from the UHF antenna heading. I chalked that up to different reflections of the knife-edge signal than I had seen on UHF, and initially installed the CS600 at the same height, facing in the same direction.

A quick test with a Zenith DTT901 NTIA converter grabbed WRGB-6, WNYT-12, and newcomer WNYA-13 with no difficulty. But WXXA-7 was intermittent, and now WMHT-34 (PBS) was becoming problematic to receive. This wasn’t going to be easy! (It never is…)

ZEROING IN

In my January conversations with Fred Lass, he mentioned that the refraction angle for channel 6 could be more severe than that of the UHF DTV stations. That meant I might have more luck if I lowered the CS600…and that’s exactly what happened.

After a night to clear my head and socialize with my relatives, I walked outside early the next morning, connected my spectrum analyzer, loosened the mast bracket, and lowered the CS600 to within a foot of the ground. I also rotated it south to the same antenna heading (230 degrees) that I eventually used to clean up reception of WMHT-34 on the Channel Master 4308.

 

After firing up the DTT901, I was finally done. All eight of the Albany DTV stations were now coming in reliably, free of dropouts. WXXA-7’s waveform, although still somewhat bowed, was considerably cleaner than before. And a modest amount of tilt on WNYT-12 and WNYA-13 was no problem even for the adaptive equalizers in my Gen 5 OnAir Solution HDTV-GT receiver.

In fact, I had enough signal out of the CM 7777 preamp to run a second coaxial drop upstairs to a bedroom, feeding a second DT901 converter box with the same results. Oddly, WRGB’s signal on channel 6 remained consistent through the CS600 at any height and with either of the compass headings I used. The 8VSB carrier wasn’t perfectly level, but the converter boxes and HDTV-GT locked it up quickly every time.

 

PROBLEM SOLVED

When TV signals bend, they really bend! Knife-edge refraction works so well at this location that I actually received all of the Albany DTV channels with the CS600 resting nose-down on the ground and its rear elements tilted up at a 45-degree angle against the mast! That certainly was cool.

The only weather effects I observed happened the last night of my stay, when dense clouds of moisture formed in the valley right before a strong weather front passed through. The resulting mist and fog caused ABC affiliate WTEN-DT’s signal on channel 26 to break up on a regular basis, while all other channels were unaffected. The next morning, all was well again. (Coincidentally, I’ve observed the same effect at home on Philadelphia’s KYW-DT, also transmitting on channel 26 and otherwise a very strong and reliable signal.)

Because the CS600 sits so low on the mast, I wrapped the longest elements with bright orange electrical tape so no one would walk into it. I also capped the swaged ends of the elements with plastic bolt protectors, glued in with silicone seal. Some new flower plantings around the antenna should keep visitors from accidentally walking into it in the future. (Don’t these problems sound ridiculous?)

 

 

Now, my brother and sister-in-law are going to try terrestrial digital TV for a month and see if they still want to pay for their existing DirecTV service. Given how little television my brother watches, I think I know how he’ll cast his vote, but I’m not sure about his wife.

I will say that she showed remarkable enthusiasm for finally having gained access to “free TV,” and she subsequently informed me that there would be a stampede for my services from nearby neighbors who’d also want in on this deal. Maybe it’s a good thing that I live almost 300 miles away?

I’m also amazed at how robust the 8VSB DTV system turned out to be, and how it’s perfectly suited to unusual propagation paths like this one. Granted, I also pulled in analog VHF and UHF TV stations with the earlier antenna setups, but the signals were fairly noisy and had more than a few ghosts, as you might expect.

Digital TV cleans all of that up. All you need is enough signal to get over the required carrier-to-noise threshold (in this case, about 20 dB C/N), and voila – perfect pictures and audio. (Never mind that a few of them were infomercials.) The fact that converter boxes and new integrated digital TV sets are largely using Generation 6 adaptive equalizers is just icing on the cake.

 


Any disappointments? Well, I never could pull in WYPX-50 from Amsterdam, although it’s strong enough to show up on my spectrum analyzer. The problem is their transmitter location, much farther west than the Helderberg Mountain antenna farm used by everyone else. That would require “sacrificing the good of the many for the good of the one” (to misquote Mr. Spock from Star Trek II: The Wrath of Khan).

Also, I could see another 8VSB carrier on channel 9 from WVER (Vermont Public Television) in Rutland, Vermont. But to receive that station would have required divine intervention, as the signal was coming from the opposite direction, 34 miles to the north/northeast over a tall range of hills, including Mt. Equinox (3,848’ ASL), and ricocheting off the 1300-foot-tall ridge in front of the house. Now, THAT would have been one heck of a billiards shot!

The good news is, if you live in a “tough” DTV reception location, you may not be completely out of luck. It helps if the DTV stations you want to receive are co-located, because having only one antenna heading to deal with is a real blessing. But there’s no reason why you couldn’t succeed with a broader antenna pattern if DTV stations are spread farther part – you just need to get enough signal to the receiver, and you’re home free.

As they used to say in those old Westerns, “Looks like my work here is done.” Time to saddle up, and head off in search of the next fringe…

Classic Pete: I’ve Got the Low-Band DTV Blues…

Did DTV channel 6 disappear on your converter box or digital TV after June 12? Here’s why it may be “MIA”…and what you may be able to do about it.

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.