Special note - If you bought a converter box, plugged it in, and don’t get some or all of the DTV stations in your area:
If you are using an indoor antenna (Rabbit Ears) and you live more than 15 miles from a station’s transmitter, you will probably need a different antenna. See the section on indoor set top antennas below.
If you connected to your rooftop antenna and your converter box doesn’t work or it works fine until the wind blows or it rains, you may be on the far side of a hill from the transmitters and will probably need a different UHF antenna. You may also need to look for a different antenna location.
Please read this article along with the rest of this paper: http://www.hdtvprimer.com/ANTENNAS/siting.html
If you have the new DirecTv DVR, you can buy a box from them that connects via USB to the DVR and allows you to record over the air HDTV signals. The model number is AM21 and it sells for $50 plus tax.
Antennas in the real world.
Updated 1/21/10.
Over the past six years I have been helping some of our viewers receive over the air HDTV. I have been surprised at the number of “problem” viewers we have been able to help. Of course, there have been those who are just in an area that is just too low in elevation, or too far away, or that has too many reflections for any antenna system to overcome but those have been relatively few.
The following section is a collection of observations collected from those 6 years. Any opinions expressed are my own and do not necessarily represent the opinion of management or staff of WRAL-TV or WILM-TV.
TV is TV. Over the air HDTV is still mostly UHF frequency radio waves.
There is no such thing as a “HDTV antenna”, they all are. Most of the antennas I have found to work best for HDTV were designed in the 1950’s. Amazingly, the boxes they are shipped in now say “HDTV”. In general, if it doesn’t look like an antenna, it probably won’t act like one. Many of the newer amplified antennas actually are worse than rabbit ears in most situations.
Indoor (set top) antennas usually don’t work more than 5 to 10 miles from the transmitter.
There are some exceptions to this such as if you live on a hill pointed in the right direction but don’t count on it. The best overall indoor antenna I have found is the Zenith “Silver Sensor”. There are others that do better in certain situations but if you want to try an indoor set-top antenna get one of these. They are usually about $10 to $20 on Ebay. The Channel Master 4220 also known as a DTV2BUHF - http://www.summitsource.com/product_info.php?ref=1&products_id=6505
or a DB-2 from Antennas Direct is an outdoor 2 bay antenna that can be used indoors if you make a stand for it. I use one piece of 1” wood dowel with a flat board screwed to it. Recently, I tried two indoor (non-amplified) antennas with a combiner (a splitter used backwards is a combiner). With the newer receivers this seems to help. You will need to find the best direction and position for each antenna by trial an error so expect to experiment for several days.
The higher the antenna, the better your chances at good reception.
Many viewers can get away with an attic mounted antenna, but some will have to mount their antenna on the roof. If you have a metal roof you can’t use an attic mounted antenna.
An antenna may have to be pointed in a very different direction than you think. Even though stations are on the same tower, they may seem to be coming from different directions.
Signals reflect off of other towers, buildings and power lines. These reflections combine with the original signal in different ways depending on what channel they are. This also can cause problems with some DTV signals. If this happens, you will get rock solid signals sometimes, but when the wind blows or it rains, some channels will break up. Often this can be fixed with a different antenna such as a Channel Master 4228.
Where you put an antenna and where it is pointed can make a big difference.
When we send out an antenna we suggest the viewer try it in their attic first. We suggest they run a temporary wire through the attic door and try the antenna in several locations usually by setting it on a box or leaning it against something depending on which type of antenna it is. We do this because moving an antenna as little as one foot in any direction can make a drastic change in how it picks up signals. As I said above, the direction the antenna is pointed makes a big difference also. If you move an antenna you need to check which direction has the best reception at the new location. Don’t assume it is the same direction as the last antenna location. When locating an antenna you must check the reception of all the stations you want to receive. When moving or aiming an antenna, have someone watch the antenna pointing screen on your HD receiver while you slowly turn the antenna. Aim for the most stable signal even if it is not the highest one you find. Check the reception on all the channels you are trying to receive. If the attic does not work, you will need to do a roof mount. Most people will need an installer to do this. If your installer picks a spot on the roof and doesn’t check for the best location he probably has a 50-50 chance of getting the signals you need. If you want to pick up all the DTV signals in your area, you may need an antenna rotor.
Don’t use an amplifier too close to a TV station.
Unfortunately, this means any TV station, not just the one you are trying to receive. In general you need to be about 15 miles away from any TV stations. Go to WWW.antennaweb.org and you can get a list of all the stations and how far they are from you. If you are too close to one TV station and are trying to get another one far away, you may need a “notch filter” to cut down the nearby station. Also, many amplifiers are not effective due to a high “noise figure”. Don’t use an amplifier with a noise figure higher than 3.5 to 4db. I have found that amplifiers with a noise figure of 6db or higher actually make DTV reception worse. Usually more antenna is much better than more amplifier.
There is no simple one size fits all answer for what antenna to use.
That being said, I will say that I have had the best luck with the following combinations:
• Within 30 miles of lightly rolling hills or 15 miles of rough terrain, I usually recommend a Channel Master 4220.
• 30 to 45 miles of rolling hills or 15 to 30 miles of rough terrain, I usually recommend a Channel Master 4228. Sometimes I recommend a 4228 even closer due to extreme terrain or reflection issues.
• 45 miles and farther out of rolling hills or 30 miles farther out of rough terrain, I usually recommend a Channel Master 4228 with a 7775 or equivalent preamp.
I specify Channel Master Antennas because we have a good working relationship with them and their factory is in North Carolina. Winegard and the other antenna manufacturers all have equivalent antennas and most are just as good. Some may even be better.
The Channel Master 4228 is about 3 feet by 3 feet by 6 inches. The 4220 is about 18” by 18” by 4”.
Email questions to WRAL-TVengineeringinfo@wral.com noting that you are a viewer in the Wilmington area.
The most extensive website I have found to date on antennas is:
http://www.hdtvprimer.com/ISSUES/erecting_antenna.html
Also see: http://www.hdtvprimer.com/ANTENNAS/siting.html
Please bear in mind that I am not the absolute RF and HDTV reference. I am just trying to relate some of my experiences because I see many people ending up in the same place. None of them are happy to be there and by the time most of them get to me, they are very unhappy.
I hope this helps.
Matt Brandes
Engineer
WRAL-TV/DT – WRAZ-TV/DT – WILM-TV/LD
1/21/10
