Does Bigger = Better when it comes to TV Antennas

[the_importer]

Been doing some research to see how it would be possible to get the OTA HDTV channels from America in my Canadian city. According to TVfool.com, the location for all 4 major US broadcasters is 87 Miles from where I'm located and the only roof mounted TV antennas that I could find that covers this length would be almost 15 feet long !!

Hard to believe that in 2012, bigger still = better. There must to be some other way to boost the power of something smaller to do the same job, no ?

[jagabo]

You need a big antenna to get the enough signal to noise ratio. There's no way around it. It's the laws of physics.

[MOVIEGEEK]

Yep "line of sight" will always be a law for all RF transmissions over 30MHz, if your antenna isn't big enough and high enough then the terrain gets in the way. Amplifiers can only do so much, if most of the reception is noise then that's what it will amplify.

[the_importer]

Yep "line of sight" will always be a law for all RF transmissions over 30MHz, if your antenna isn't big enough and high enough then the terrain gets in the way. Amplifiers can only do so much, if most of the reception is noise then that's what it will amplify.

So what about one of these that will get 60 miles and I add a booster, think I could get Fox, ABC and CBS which are 88 miles away from me?

[usually_quiet]

So what about one of these that will get 60 miles and I add a booster, think I could get Fox, ABC and CBS which are 88 miles away from me?

Probably not. Especially if TVFool has indicated any of the distant stations you are trying to receive are are 2nd edge, or troposphere.

Remember, amplifiers amplify both signals and noise.If you don't have a sufficiently strong good-quality signal, an amplifier won't help. You will just have a stronger poor-quality signal.

[edDV]

If you want serious help, run your address through TVFool, post results here (without address) and I'll analyze your options.

My closest station here is ~60 mi and 2Edge but I still get 2Edge VHF out to 130 mi.

If you are Toronto area we have done this a few times. If so you are fortunate to have Lake Ontario in the way, not 3000 Ft mountains.

[Bjs]

level II fringe reception ... around 6'

The picture is a unit designed for issues related to digital crossover backwash ... ex : in between towers.

[edDV]

I'll walk you through a generic analysis for downtown Toronto.

1. Directional Plot (digital channels) You can see here that the USA transmitters of interest are grouped at 151 degrees south near Buffalo. There is a second grouping of more distant transmitters near Rochester.



2. Transmitter Location. It isn't enough to point an antenna at a city. Most TV station transmitters are not located in town, but on the highest hills/mountains outside town. This is very important for distant reception because the curvature of the earth comes into play at about 60 miles. The way to peak above the horizon is to raise the height of the transmitting or receiving antenna. For this reason, the Buffalo TV stations locate their transmitters southeast of the city on the highest land even though it increases the distance to Toronto (79 to 82 miles).



When you look at this map of transmitter locations, you see that the transmitters are grouped making a high gain directional antenna work for all.

3. Transmitting Frequency - The next chart shows the details for all transmitters. Note that all are in the UHF band (Ch14-51) except WBBZ which is on channel 7 in the upper VHF Band (Ch7-13). Reception in the VHF band requires a separate and much larger antenna. Since WBBZ is on a minor network (ME-TV), you can simplify reception choosing a UHF only antenna.



When you look at the chart above several other issues are raised. All UHF transmitters except WGRZ are line of sight with no blockage. WGRZ has one geographic feature blocking reception (1Edge) as shown in the plot below. In order to receive this station the signal must bend over the obstacle (shown by the blue). Expect this channel to come and go with weather conditions. You can also see from the chart above that the Rochester transmitters are all below the horizon (tropo) or have two obstacles in the path (2Edge). Also note that two of the major Rochester stations (ABC and NBC) are in the VHF band. Your cable company has no problems receiving Rochester because their antenna is on the CN Tower (or signal is delivered by fiber).

[edDV]

The analysis above applies to downtown Toronto. Other locations will vary for distance and obstacles in the path.

So this points to a highly directional UHF antenna that can reach 80 miles.

The Channel Master antenna you showed is on the marginal side. These two might do better. The 91-XG is the most directional and has the highest gain.


Note Dimensions 22" H x 20" W x 93" Deep
http://www.antennasdirect.com/store/91XG_HDTV_Antenna.html



Dimensions 29"L x 42"W x 4"D
http://www.antennasdirect.com/store/DB8_HD_Antenna.html

Either will benefit from a mast mounted pre-amp.
http://www.antennasdirect.com/store/UHF_VHF_antenna_pre_amp_kit.html
http://www.summitsource.com/winegard-ap8283-antenna-preamplifier-chromstar-series-outd...83-p-4576.html

Or look for neighbors with antennas and ask them about reception.

[edDV]

There is a second set of tools (Callsign Lookup) that shows reception from the transmitter point of view. This plot shows the 1Edge station WGRZ (NBC). You can see that the low elevation Toronto areas near Lake Ontario (blue) are subject to the 1Edge blockage but some higher elevation areas inland get the direct signal (pink). You can zoom this map down to street level to get a prediction of reception from that particular transmitter.



You can also add TV and FM radio transmitter sites into Google Earth to observe the terrain obstacles between the transmitter and reception site. In this case, the land is mostly flat.



Or looking the other way from Toronto ...

[lordsmurf]

Stability and line of sight are just as important as size.
If you put an antenna on a wobbly pole, forget about a stable signal.
If your big antenna is in the attic, forget about high quality signal from far away.