Topic Broadcast-tv-enginee

TV antennas - OTA HDTV reception

in broadcast-tv-enginee on (#2SG5)
Cable/satellite TV is a huge expense (typically over $700 per year), which is completely unnecessary for anyone in the US located within 100 miles of a major city.

With the switch to digital HDTV, the picture will look BETTER than any cable/satellite transmission, AND digital sub-channels mean most people end up getting DOZENS of TV channels.

What's more, you'll find that 95% of good, original TV programming is on broadcast TV networks. For a few others shows you can't stand to miss, you may find that Netflix and Hulu can provide them, at far less cost than maintaining a cable/satellite subscription, and come with other added benefits, too.

Since the HDTV switch-over, OTA (over the air) TV reception is actually growing, at the expense of cable/satellite:

To get an idea of what TV signals are in the area, at what strength, and in which direction(s), input your address on TVFool, and look at the digital stations available to you:

Practically all broadcasters on VHF-low (channels 2-6) are dropping their existing channel assignments, and switching to a higher (UHF) one. There are very few exceptions. There are also some (much lesser) signs of broadcasters leaving VHF-high (7-13), likely due to the FCC charging up to 3X as much in annual fees for VHF licenses versus the equivalent UHF, which they've only recently rectified (2014). But for the time being, there are lots of VHF-high channels, so you will need an antenna that can receive channels 7-13. However, with "repacking" after the FCC incentive auction, it's quite possible that this trend will reverse completely after about 2017 or so, when broadcasters in your area may be ordered to change their frequencies.

STRONG SIGNAL (0-20 miles):
If you are just a few miles from all the TV stations you want to receive, and there are no obstructions in the way, you would probably do well to just get a TV-top antenna that does both VHF and UHF ("rabbit ears" for VHF, and a "loop" or "bow-tie" for UHF). They are best placed in-front of a window, facing towards the broadcasting towers. If you have obstacles, are near the maximum distance, want to serve a number of TVs, or otherwise reception is simply poor, see the next section (below).

You do NOT want an antenna with a knob on it, meant to allow fine-tuning of reception for old analog signals. With a strong enough signal, those will mostly work in a few settings, but you'll have to keep switching them back and forth every time you change channels, to get ANY picture. You should not assume that the poor performance of an old antenna like this, which you already have, will give you a proper idea of typical reception with a proper replacement.

Also, an amplifier on an indoor antenna is either completely useless or may even hurt reception. They only help with very long coax cable runs, or if you are splitting one antenna out to several different TVs.

Here's a cheap, basic set-top VHF/UHF antenna:

MEDIUM SIGNAL (20-40 miles):
Don't get an antenna that is large, and/or highly directional with high gain (db) or else it will be unnecessarily difficult to install and aim the antenna. Hopefully all the channels you want to watch are coming from the same general direction, otherwise, you'll need a (low-end) antenna rotator to get a good signal. Two antennas pointed in different directions really doesn't work well, unless you have a very strong signal.

Unless the UHF and VHF signals are coming from very different locations, you'll probably want to get a single VHF/UHF antenna, to keep costs low.

Here's one of the cheapest outdoor antenna I could find, and it includes a basic rotator, preamp, 40ft of RG-59 coax, and a 2-way splitter built-in:

Supersonic SC-603 VHF/UHF

Here's a higher-powered option (but without the rotator, preamp, etc.):

AntennaCraft AC9 VHF/UHF

With the SC-603, I can get very "Good" signals on digital UHF stations down to -85dBm (according to tvfool), but then nothing at all below it, perhaps because this antenna is poor at rejecting the co-channel interference common on those. Analog UHF stations below -75dBm had lots of static and were unpleasant to watch. VHF stations were a bit weaker, and none came close to proper reception, so expect the VHF gain to be pretty poor.

Don't pay too much attention to product specs... Any manufacturer will lie through their teeth, claiming 200+ mile reception with a $10 antenna, but it is just nonsense. The size and design (not specs or price) will tell you what kind of reception you will get, and unbiased customer reviews are most helpful (as on Amazon, but NOT SolidSignal or similar).

If you do need separate UHF and VHF antennas, I suggest a 4-bay antenna for UHF, and something small like an AntennaCraft Y5-7-13 for VHF-hi. 4-bay antennas are hard to find, now, but almost any 8-bay antenna can be used as two separate 4-bay antennas, with the purchase of a few extra u-bolts...

4-pack U-bolts with nuts and plate

AntennaCraft Y5-7-13 VHF-high

To connect both of them to a single coax cable, DO NOT USE A REGULAR SPLITTER or you'll ruin your reception for no good reason. You want a $10 UHF/VHF combiner, usually labeled "USVJ", made by Pico Macom/Blonder Tongue/Holland/etc. Or this may feature MAY be included by mast-mounted preamplifiers (see below).

Pico Macom--Tru Spec UVSJ

I recommend an 8-bay antenna for UHF. One of the top performers, (and significantly less expensive than other 8-bay antennas) is the Winegard 8800. Any 8-bay performs quite well at the lower range of UHF frequencies from 14 to 51. A yagi+corner reflector like an AntennasDirect XG91 (and the dozens of cheaper models commonly seen on roof-tops) will out-perform it only on the highest channels (62-69), which are no longer used for broadcast TV. It's stunning to read the Amazon reviews on the XG91 in particular, where people will admit they have more channel break-up than with an old 8-bay, but it's still better because their TV's signal meter show slightly more bars!

Winegard 8800 8-bay UHF

A few 8-bay antenna manufacturers claim their product gets good VHF performance, but it's all misinformation. At best, they only barely outperform the most basic "rabbit ear" type designs. If you're far enough from UHF stations that you need an 8-bay, you're probably also far from VHF stations, and need a GOOD VHF antenna to bring in the signal. A barely-capable-of-VHF 8-bay simply doesn't have enough gain to get decent VHF reception. A $20 VHF-high antenna will blow them all away. And make sure you use a "UVSJ" VHF/UHF combiner, NOT a standard splitter to connect them (linked above).

One other advantage that multi-bay antennas have over yagi+corner reflectors is size/depth. If you are renting an apartment, you are allowed to install any antenna you want on your property. Multi-bay antennas are pretty flat, and could mount even just on an outside window ledge. Just make sure to mount it securely, because they can be pretty heavy. If there's no location for installation outdoors, you could also install it on the inside of a window, facing out, perhaps hidden from view by your curtain... a yagi would stick out, halfway across the room.

FCC "OTARD" Antenna Placement Rules

VHF antennas are pretty straight-forward. The longer, the better. Outside of Alaska, you probably don't need VHF-lo reception, so a VHF-hi antenna can give good gain, at a smaller size and price. The AntennaCraft Y10-7-13 (120") is a popular model for fringe reception, and is widely available, while fairly inexpensive. For less-distant reception, the AntennaCraft Y5-7-13 is about half-price, and half the size.

AntennaCraft Y5-7-13 VHF-high

AntennaCraft Y10-7-13 VHF-high

With a Winegard 8800, I'm able to get digital UHF signals down to almost -120dBm, and great picture quality on analog stations even with attic mounting. Covering the back-side with aluminum window screen materials improves reception just slightly, but greatly cuts down on interference from signals directly behind the antenna.

With a Y10-7-13, I can get strong signals on digital VHF stations at -91dBm, but then around -95dBm things break-up frequently. VHF antennas don't get as much gain as UHF, so you need a slightly stronger signal, even with the best antennas available.

And if your signal levels are too low, pairing-up two of the same antennas together can give quite a significant gain of 3dB, which is a doubling of signal strength, since dB is a logarithmic scale... And raising your antenna mast to double the height will again give you an extra 3dB, or double the signal. But beyond 150 miles from the transmitter, you're really not going to be able to get regular reception, unless you're on top of a mountain.

If you're going to run the coax straight down from the antenna, directly through a wall and to a single TV, there's almost no benefit to be had from a preamp / signal amplifier. If, however, you're going to run long cables all around your house, split the signal up for 4 TVs, etc., a mast-mounted preamp is invaluable, and will make a TV antenna perform much more like cable.

It's important to remember that you've got to supply power to the preamp. This means you'll need the coax running indoors to a power outlet, either before hitting a splitter, or on a "power passing" leg of a splitter, as many (most?) are now designed to accommodate preamps. If you don't properly connect the power injector, you'll get a terribly weak signal, until you get it all sorted out.

Choosing a preamp was more complicated before, but today, you can either go for a cheap but quite decent preamp like the widely available RCA unit, or spend about twice as much for the top-of-the-line Winegard LNA-200 Boost XT.

RCA TVPRAMP1R Preamplifier

Winegard LNA-200 Boost XT

The "noise" figure is the significant part. If your TV/tuner needs 6db of signal, and you buy a cheap preamp that has 5db "noise" spec, it might actually hurt reception. Meanwhile, the LNA-200's 1db "noise" spec is lower than any tuner, and should improve reception, except in a few extreme cases like signal overload. I've done side-by-side comparisons, and the LNA-200 XT absolutely does offer a slight improvement over cheaper and older preamps. I don't suggest replacing a working 3dbN preamp, unless maybe you're just right on the edge of one specific channel coming in clearly... However, note that the RCA unit has separate VHF/UHF inputs, saving you an extra $10 on-top of the lower purchase price, by eliminating the need for a UVSJ.

You don't need to think about the "gain," or other "distribution" amplifiers, unless you have EXTREMELY long cable runs, and/or are splitting out to a dozen TVs.

A DVR/PVR is a must-have item. Not only can you pause live TV, and skip commercials so each program is 1/3 shorter, you will also find that you quickly accumulate more TV shows than you can watch. When you never miss an episode, and can select from shows airing while you're working or sleeping, the extra hours of viewing really add-up, and necessitates a change in viewing habits. A DVR simply multiplies the value of any and every channel you have available.

Today, the most basic DVRs are very cheap, though you do notably lose the ability to watch one show, while another is being recorded with the current generation of this cheap hardware. They work by having a USB port that you must use to plug-in a hard drive for storage.

$50-100 for the USB drive. I suggest small, 2.5" USB bus-powered drives, only.

Toshiba Canvio Connect Portable Hard Drive

$30-50 for the DVR/tuner box... Ematic / ViewTV recommended:

Ematic AT103B tuner/recorder

Viewtv At-163 tuner/recorder

I can't generally recommend anything other than the Ematic or Viewtv. Unlike most other similar boxes, they do proper (analog-)signal pass-through while the box is powered-off, which makes wiring for the others a big problem. They also have stable firmware without some of the bugs other boxes notoriously suffer from.

The EMatic happens to be the cheapest, but recent units have noticeably worse reception, so the ViewTV box may be worth the extra money. I strongly suggest avoiding the IVIEW brand boxes, due to HORRIBLE warranty terms ($20 repair shipping charges), terrible remote, and all manner of endless firmware bugs.

Cheapest antenna mast option I've found is a chain-link fence "top rail". $11 for 10ft segments at local hardware stores, with tapered ends that allow them to fit together. To connect multiple 10ft segments together requires drilling a couple holes and bolting them together, but nothing more expensive or involved is required, unlike other types of bulk pipe. Don't cheap-out on heavy-duty bolts and nuts, though!

10ft x 1 3/8" 17 gauge Galvanized steel top rail

If you're mounting to a wall, overhang, etc., make sure the screws for the mounting bracket get a good solid grip on a nice sturdy stud. The forces involved are impressive. And if you're only using one mount at the top, and resting the bottom on the ground, make sure it's buried at least 6 inches deep, preferably inside a buried cinder block or similar. If you don't give any thought to the footing, the leverage will be enough to just push aside a 1-inch wide channel of dirt, bend the top bracket or break your eaves, then collapse on your roof.

Channel Master heavy-duty 4" (wall-clearance) wall mount

Channel Master heavy-duty 12" (wall-clearance) wall mounts

The typical recommendation is that no segment should be taller than 10ft (above the top mounting bracket), without the use of guy wires. Otherwise, expect lots of flexing in high winds, and the possibility of the antenna mast collapsing.

Chimney-mount hardware is inexpensive and works great, either for an actual chimney, or other large and heavy roof-top items, like an air conditioner condenser. The actual straps can be substituted for plumbers tape/pipe strap if desired, but the two angle-iron brackets and other in