Posts Tagged ‘Bow Tie’

Useful Gadgets: TERK Omni and Turbo Indoor DTV Antennas

I have to give Terk credit for continuing to roll out innovative designs for indoor and outdoor TV antennas.  Going all the way back to 1998, when I tested my first Terk design, there have been some pretty interesting-looking products in their line (not to mention some strange ones, too!).

Unfortunately, the performance of these antennas hasn’t always matched up to their looks, and the new Omni and Turbo indoor models aren’t breaking that mold any time soon. The bar that any indoor TV antenna must overcome is pretty high: They must have gain at the specific frequencies; enough of it to overcome multipath distortion and echoes – a given indoors – and also to provide a sufficiently-high signal-to-noise (SNR) ratio so that reception is free of drop-outs.

The Omni (model OMNITWR, no price yet) is a black plastic tower that stands about a foot tall and has a blue LED illuminating ring on the bottom. Terk calls this an “amplified multi-directional HDTV antenna” which “receives 4K Ultra HD Broadcast” (never mind that there aren’t any yet) and “Supports 1080p.” The packaging goes on to promote free HDTV from the familiar networks (ABC, CBS, Fox, NBC, CW, PBS, and Univision) and proclaims it is “a great compliment to streaming players.”

Well, Terk and I agree on that last point, at least. Free off-air digital TV is a great compliment to streaming channels. If you can get CBS off-air, why pay $8 a month for it? For sports fans, there are still quite a few marquee events that are broadcast on free channels, and for ‘retro’ fans, more and more secondary minor channels like Antenna TV, Comet, and MeTV are full of classic old TV shows (many in thrilling black and white!) from the 1950s, 1960s, 1970s, and even the 1980s.

Elsa can’t figure out if the Omni is a scratching post or not.

As for Terk’s other claims; antennas pull in RF signals, such as TV channels. Those channels can carry digital information in the ATSC format in the U.S. or in the DVB format used elsewhere in the world. The demodulated broadcast signal can be standard definition (480i) or HD (720p and 1080i). It’s the TV that demodulates the signal, NOT the antenna – all the latter does is receive the RF channel.

So technically, the Omni (and any other indoor or outdoor antenna, for that matter) can receive 4K broadcasts. They could also receive 1080p HD broadcasts, although that format isn’t used by any television station. Yes, the $4.99 bow-tie antenna I use in all of my tests could also receive a 4K broadcast! (How’s that for mixing contemporary with retro?)

Terk’s Trinity Xtend Turbo antenna (Model WITRIAC, $129.99) is another indoor antenna design that is shaped like a book. You can lay it flat or mount in vertically for TV reception. But it does double duty as a WiFi extender, working with dual-band (2.4 and 5 GHz) systems that use the 802.11ac channel-bonding protocol. So you can watch TV and extend your WiFi range, too!

The shipping box touts “802.11ac up to 3X faster than 802.11an.” Well, that should be the case, as you can bond two, three, and even four channels in the 5 GHz band to increase data speeds, but that’s a WiFi protocol not related to DTV reception. As before, Terk claims this antenna will receive 4K broadcasts and supports 1080p, and we don’t need to go down that road again.

But there’s one additional claim that was hard to swallow: A reception range of 65 miles, which would be some manipulation of the laws of physics for such a small antenna! I’m hard-pressed to receive signals that far away using a combination 5-element VHF and 15-element UHF antenna system equipped with a 24 dB mast-mounted preamplifier. But I suppose it’s possible that reception over that distance might be possible if (1) you lived on a mountaintop with a long view to the horizon, (b) happened to be watching UHF TV channels during a tropospheric ducting event, or (c) were watching terrestrial TV on the international space station.

I tried the Trinity Xtend horizontally polarized…

…and vertically polarized.

ON THE TEST BENCH

All’s fair in love and war, so I decided to test both antennas against my reference bow tie antenna. There’s a sweet spot in my 2nd floor home office where DTV signals from Philadelphia are strong enough to be captured with an indoor antenna, so I ‘borrowed’ my cat’s elevated perch and use that to support all of the antennas. Just for fun, I dusted off an amplified Mohu Leaf to compare tests, and to provide a bit more ‘kick’ to the bow tie, I pulled out the Antennas Direct ClearStream JUICE preamp so that all antennas were playing on a more level field.

Each antenna was placed in the ‘nest’ and aimed for best-looking waveforms on a spectrum analyzer. Then, I scanned up and down the band to find which channels were received reliably, i.e. that is for at least a minute with no dropout. In the Philly market, we’ve got a couple of low-band VHF stations, a few high-band VHF broadcasters, and more than a few UHF signals that should be easily received.

Laugh if you want at this ancient antenna design, but it can run circles around upstarts!

 

Table 1. A comparison of all the antennas under test. None of them could pull in WTXF on channel 42.

Table 1 shows the results. I was quite surprised by how well the bow tie performed, but perhaps I shouldn’t be. This classic design more than holds its own repeatedly in tests against more expensive models with gimmicky packaging, and it’s over 60 years old. With the JUICE preamp, it pulled in eight out of ten stations, missing WBPH-9 and WTXF-42. (None of the antennas could help Fox’s signal, despite it looking pretty clean and strong on my analyzer.)

2nd place went to the UHF bow tie without the preamp, which hauled in seven stations. Not bad for $4.99! Mohu’s time-tested Leaf with external amplifier was right behind, providing reliable reception of six out of ten stations. Terk’s Omni was not up to the task even after I tried a second position for it, pulling in four out of ten stations the first time around and three of ten on the second try. In its defense, it did snag WLVT-39 from Allentown, which only the amplified bow tie could match.

Compact antenna designs will have trouble with low-band VHF reception.  KJWP-2 and WPVI-6, as picked up by the amplified bow tie…

…are basically ‘missing in action’ on the Terk Omni antenna.

As for the Trinity Xtend? Best to use it as a WiFi extender and forget about DTV reception altogether, unless you live very, very close to the transmitters. No matter which way I oriented it – vertically or horizontally – it could only pull in two stations reliably (WYBE-35 and WFMZ-46) and neither of them is affiliated with a major network. (So much for the claim of 65-mile reception.) My location is around 25 miles from the Roxborough TV towers and has moderate multipath, but not so much that the average indoor antenna can’t pull in at least five stations.

As for the WiFi extender part; it works quite well. I downloaded the Terk Extender app from Google Play and it didn’t take long to make the connection while following the app’s instructions, boosting 5 GHz signal strength by a few decibels in the farthest parts of my house. So you may still find that part of the product useful if you are strapped for range.

Terk’s Trinity Xtend created a ton of spectral noise on high-band VHF channels 7 through 13…

…that wasn’t seen at all when using the amplified Mohu Leaf.

Here are channels 17 through 46 as picked up by the amplified bow tie.

The same channels using the Terk Omni…

…and the Terk Trinity Xtend, lying flat (horizontally polarized).

CONCLUSION

As you’ve seen in previous tests, there are some really good indoor antennas for sale that won’t break the bank. Winegard and Mohu both offer indoor panel antennas (passive and amplified) that should pull in the majority of stations in your area if you are no more than 30 miles from the TV transmitters. Radio Shack doesn’t sell UHF bow ties anymore, but Amazon shows the ANTOP amplified bow tie for about $28 – a little pricey in my book, but having the amplifier is a plus.

There’s a catch, though. The recent FCC spectrum auction just concluded and it appears that all UHF channels above 38 will be re-allocated for other uses. This means there are plenty of TV stations that will have to relocate, and some of them will wind up in the noisy, harder-to-receive low-band VHF channels from 54 to 87 MHz. Antennas must have more and longer elements to work at these frequencies, so super-compact designs aren’t going to cut it in the future.

With that in mind, I can’t recommend either of the Terk models for indoor reception – not when a five-dollar piece of bent wire can outperform both of them. Oh well; better luck next time…

Useful Gadgets: Indoor DTV Antennas – The Third Time’s The Charm

Earlier this year, I posted a couple of product reviews of indoor digital TV antennas. The first test, posted on April 6, concluded that there isn’t a heck of a lot of difference between a $5 bow tie and a $40 ‘flat’ antenna when it comes to VHF and UHF TV reception.

The second test, posted on May 29, gave one manufacturer a ‘do-over’ as their original product didn’t perform all that well and was judged to be defective. And that test also included a newcomer who didn’t make the original cut. (Believe it or not, both tests grew out of a more impromptu test in my house of a couple of panel antennas!)

Since the Round 2 results were posted, three things transpired. First, I became aware of yet another indoor DTV antenna, called the Clear Cast X1 and sold through Sunday newspaper inserts, magazines, and even on this Web site.

According to Clear Cast, “Advanced patent pending design of the X-1 digital antenna pulls in free over-the-air digital and HDTV broadcasts in your area so you can leave behind cable-only channels & expensive cable & satellite bills. Receive crystal clear digital picture on any digital TV in the house with NO monthly bill, easy install and setup plus NO waiting for the cable guy.” OK, I was intrigued enough to order one (they’re not cheap!)

Secondly, the PR firm that represents Antennas Direct – the company that shipped me a Clear Stream Micron XG for Round 2 testing – inquired why I hadn’t tested the accessory reflector with the antenna. (Simple: As Steve Martin used to say, “I forgot!”)

Finally, the Mohu Leaf Plus that self-destructed in Round 2 had been replaced and was ready for another go. (The amplifier failed, a problem Mohu was aware of and corrected in subsequent production.)

So it was clearly time for one last trek to Mountain Lakes, NJ to put all of the antennas from Round 1 and Round 2 through one more workout. I loaded up my spectrum analyzer, computer, several spools of coax, and a few splitters and headed out to put this test to bed once and for all.

THE TEST

For Rounds 1 and 2, I used the same window as the desk in front of it was unoccupied at the time. This time around, I opted for a slightly different location between two desks so that I wasn’t interfering with everyone’s work. Additionally; since the test position had now shifted by about six feet, I decided to re-test every antenna from Rounds 1 and 2 to be consistent and fair to all.

Here's what the test site looked like.

 

And here's the 'reference' bow tie antenna taped to the window.

I was assisted in my endeavor by John Turner, the owner and president of Turner Engineering and a long-time veteran of the broadcast systems integration world. Using AVCOM’s PSA-2500C spectrum analyzer, we positioned a $4.99 Radio Shack bow tie antenna (no longer available) for best reception of WNJM-51 (now known as “NJTV”) out of Montclair, NJ.

I also connected a Hauppauge Aero-M USB stick DTV received to pull in each station, in tandem with the TS Reader MPEG stream analyzer program to verify reliable reception (i.e. low bit rate errors). Each antenna under test fed the spectrum analyzer and Aero-M through a two-way splitter, and each antenna was placed in exactly the same spot on the east-facing window, using four pieces of masking tape as markers for alignment.

For each test, I scanned for channels using the Aero-M receiver. Next, I scanned each physical TV channel that was received with TS Reader to see how clean that stations’ MPEG stream was. Finally, I captured screen shots of the actual waveforms from each station I received. And if those three steps didn’t prove which antenna works the best, I don’t know what would!

THE RESULTS

For the record, here are all of the test antennas:

 

Radio Shack bow tie ($4.99, no longer offered, but you can find them on eBay)

Clear Cast X1 ($68 plus shipping)

Walltenna ($35 plus shipping)

Mohu Leaf ($38 plus shipping)

Mohu Leaf Plus ($75 plus shipping)*

Winegard FlatWave ($40, free shipping through August 31)

Antennas Direct ClearStream Micron XG ($100 plus shipping)*

* – amplified, or comes with optional amplifier

 

For my tests, I scanned for all New York City and New Jersey DTV stations within range of Turner Engineering. One local station (WMBC-18) was so strong that I essentially discounted it from my test results – it would have come in with a paper clip!

The Clear Cast X1 is definitely NOT worth $70. Let the buyer beware!

 

But other stations weren’t quite as strong. WABC-7 is a good test of high band VHF reception, inasmuch as every antenna in the test is supposed to pull in both VHF and UHF signals. WNJB-8 in the Watchung Hills of New Jersey is another good test of VHF reception.

For UHF signals, I checked out WNYE-24 (atop the Empire State Building), WNBC-28 (also on Empire and usually strong), WFME-29 (in West Orange, NJ), WFUT-30 (on Empire), WCBS-33 (Empire), WWOR-38 (Empire), and WNJM-51 (Montclair, NJ).

I didn’t expect the antennas to have much luck with WABC or WNJB, as they are too small to have much gain at VHF frequencies. The amplified antennas were a different story, though. If you are aggressively marketing indoor TV antennas for ‘all band’ reception, then you’d better deliver!

Table 1 shows how the unamplified antennas compared to each other. Satisfactory reception is indicated by glitch-free video streams for at least one minute and a ‘clean’ reading with TS Reader, while Table 2 shows how the amplified antennas (or amplified variations) compared.

Yes, you can actually attach the Micron XG to glass with masking tape! (The reflector was a tad more difficult to install...)

 

Note that the ClearStream Micron XG was tested three different ways –‘ bare bones’ with no amplifier or reflector in Table 1; with its amplifier switched to 15 dB mode in Table 2, and with the amplifier on and the accessory reflector attached in Table 2.

 

Antenna

WABC-7

WNJB-8

WNYE-24

WNBC-28

WFME-29

WFUT-30

WCBS-33

WWOR-38

WNJB-51

RS Bow Tie

Yes

No

Yes

Yes

Yes

Yes

Yes

No

Yes

CC X1

No

No

Yes

Yes

Yes

Yes

Yes

No

No

Walltenna

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

Yes

Mohu Leaf

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

Yes

FlatWave

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

Yes

Micron XG

No

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Table 1 – Unamplified antenna performance

 

Antenna

WABC-7

WNJB-8

WNYE-24

WNBC-28

WFME-29

WFUT-30

WCBS-33

WWOR-38

WNJB-51

Leaf Plus

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

Yes

Micron XG w/amp

No

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Micron XG w/amp and refl.

No

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Table 2 – Amplified antenna performance

 

Oddly enough, the Micron XG was the only unamplified antenna to pull in WWOR-38. But it was ‘tone deaf’ when it came to the two high band VHF stations. Neither version of the Mohu Leaf could snag WWOR-38, either.

As for the vaunted Clear Cast X1, it was unresponsive to any VHF channels and couldn’t hear local station WNJM-51. In contrast, the late, lamented Radio Shack bow tie worked exceptionally well on just about every UHF channel.

Bonus reception: WNJU-36, which is a tough signal to pull in at this indoor location, was successfully reeled in by the Micron XG with amplifier and reflector. So was WXTV-40, also pulled in with and without the accessory reflector.

THE CHARTS

I’ve included a few charts to show what the actual DTV received signals looked like on the AVCOM analyzer. You may be surprised to see how small the differences are between each antenna, and you will also note that the reflector didn’t improve reception at all on the Micron XG – in fact, it actually made things worse, probably due to all of the signal reflections and multipath at the test site.

As a reference, the actual signal levels shown are about 12 dB stronger at the displayed resolution bandwidth (300 kHz).

Here's what the RF spectrum looks like from channels 18 to 51, using the bow tie antenna.

 

And here's the same spectral view using the Clear Cast X1...

 

...using the ClearStream Micron XG...

 

...and using the Mohu Leaf (no amplifier).

 

Here's channel 51, the former WNJM, as received on the bow tie...

 

...and here's the same station on the Clear Cast X1. No improvement.

 

Winegard's FlatWave pulled in channel 51 more robustly...

 

...as did the Walltenna.

 

Finally, here are received waveforms for WNJU-36 and WWOR-38, using the ClearStream MIcron XG with the amplifier set to 15 dB, but minus the reflector...

 

...and here's what those same waveforms looked like AFTER I installed the reflector. Reception actually worsened, something I saw on numerous other UHF channels. Indoor DTV reception can be funny that way!

CONCLUSIONS

It’s hard to make much or an argument for spending very much money on an indoor DTV antenna when you see how well the lowly $5 bow tie design performed! This antenna design has been around since the 1950s and is just one of those things that can’t be improved on – unless you build an array of them. (‘X’-shaped colinear UHF antennas perform the same as the bow ties.) It’s just unfortunate that no mainstream electronics retailer sells these anymore. (Hey Radio Shack, are you listening?)

However, it’s easy to make the argument that the Clear Cast X1 is definitely not worth spending $70 on, especially since it was easily outperformed by the far less costly Leaf, Walltenna, and FlatWave antennas. Even the bow tie picked up six more stations than the X1 in my overall tests, two of them on VHF. I don’t know what’s inside the plastic housing, but I’d bet it is nothing more than a simple dipole, bow tie, or loop antenna (Clear Cast’s claims to having a ‘patent pending’ notwithstanding). Keep your wallets in your pockets!

Among the basic flat antennas, I still prefer the Leaf – it’s smaller and more esthetically pleasing than the Walltenna (which still  does a good job, better than the FlatWave) and it’s been a reliable performer everywhere I travel. The Leaf Plus is a bit pricey at $75, but the amplifier – while not as powerful as that on the ClearStream Micron XG – helps pull in marginal stations and doesn’t add much to the form factor.

As for the Micron XG, I had mixed feelings about it. It’s big and somewhat blocky, expensive, and based on my tests, you can’t depend on it for VHF reception in suburban locations, a chore the other ‘flat’ antennas handled without much difficulty. In its favor, the Micron XG did pull in WWOR, something no other antenna could do. (Maybe that outcome was just a fortuitous combination of antenna position and signal level?)

The Micron XG amplifier makes a big improvement, but I’d suggest running it no higher than 15 dB. The 20 dB setting creates too much noise and also degrades weak signals, as observed with the spectrum analyzer. The lower-gain 10 dB setting is also very handy in fringe urban areas where you don’t need tons of signal, but just need to boost the carrier-to-noise ratio (CNR) a bit.

And that reflector? It’s hardly worth bothering with, as it didn’t improve reception on any of the tested channels and in some cases degraded it. Those results were puzzling, because the reflector effectively converts the antenna pattern to something resembling a two-element yagi, which should have more gain as it becomes more directional. Maybe you’d have different results over a line-of-sight (LOS) path, but that’s hard to ensure when trying to grab DTV signals indoors.

In any case, you should be able to get a decent indoor DTV antenna for less than $50. Stay away from the amplified versions unless you live in a fringe urban or outer suburban area, where there are less likely to be out-of-band sources of overload and interference. Always place your antenna near a window and/or closest to the direction of the TV transmitter(s) for best results.

Good luck!