Antennas
About TV & SAT Antennas
Selection of Terrestrial TV Antennas
This short guide has been prepared for those who would like to perform/replace antenna installation on their own and live in areas with good reception conditions.
In the case of low signals, reflexions, interferences - we advise to call experienced antenna installer who well knows the local conditions.
In the case of low signals, reflexions, interferences - we advise to call experienced antenna installer who well knows the local conditions.
Below we analyze the factors that should be taken into consideration when choosing receiving antennas.
We cannot guarantee that this advice will ensure satisfactory results in all cases.
We cannot guarantee that this advice will ensure satisfactory results in all cases.
Factors determining selection of antennas
1. Distance from the transmitter/transmitters
2. Number of the transmitters and their frequency bands
3. Angle distances among the transmitters
4. Output power of the transmitters
5. Directivity of transmitters' antennas
6. Polarizations of the transmitted signals
7. Obstacles between transmitting and receiving antenna
8. Kind of installation
9. Influence of interferences, including unwanted signals from other transmitters.
2. Number of the transmitters and their frequency bands
3. Angle distances among the transmitters
4. Output power of the transmitters
5. Directivity of transmitters' antennas
6. Polarizations of the transmitted signals
7. Obstacles between transmitting and receiving antenna
8. Kind of installation
9. Influence of interferences, including unwanted signals from other transmitters.
1. Distance from the transmitter/transmitters is the main parameter that has to be taken into account when choosing the antenna. For longer distances antennas have to ensure higher gains.
|
| Up to 10km | Up to 25km | Over 25km |
|---|---|---|---|
| Broadband antenna (planar) | YES | NO | NO |
| Logarithmic broadband antenna A4011 | YES | YES | NO |
| Set A0710 +A1910 (Yagi) | YES | YES | YES |
| Set A1116+A2682 or A3710 (Yagi) | Unnecessary | YES | YES |
Selection of antennas in relation to the distance from transmitter
2. Number of transmitters (different locations) The situation where all signals are transmitted from one place is quite rare (some cities) - in most cases we have to receive signals from two or more directions. So we have to employ a number of directional antennas. The broadband antennas (planar constructions) are not suitable for that purpose, due to wide half-power angle (ca 45 deg), which would effect in interference of signals.
Example 1
Bochnia, between Krakow and Tarnow: there are two locations of transmitters: Choragwica (Krakow), Gora Sw. Marcina (Tarnow)
Bochnia, between Krakow and Tarnow: there are two locations of transmitters: Choragwica (Krakow), Gora Sw. Marcina (Tarnow)
| TV program | TVP1 | TVP2 | Polsat | TVN | TV4 | Puls | TVP3 |
|---|---|---|---|---|---|---|---|
| Channels (transmitter Choragwica) | 10 | 33 | 53 | 30 | 35 | 27 | 50 |
| Power | high 200kW | high 300kW | high 100kW | medium 10kW | medium 10kW | medium 10kW | high 200kW |
| Polarization | H | H | H | H | H | H | H |
| Transm. antenna | omnidirect. | omnidirect. | omnidirect. | omnidirect. | omnidirect. | omnidirect. | omnidirect. |
| Channels (transmitter Gora Sw. Marcina) | - | 22 | 60 | 35 | - | - | 57 |
| Power | - | medium | medium | medium 10kW | - | - | high |
| Polarization | - | H | H | H | - | - | H |
| Transm. antenna | - | omnidirect. | omnidirect. | directional | - | - | omnidirect. |
List of programs transmitted from Krakow and Tarnow
Unfortunately, it is practically impossible to receive TVN, TV4, or Puls from Krakow - the direction of radiation is just opposite, towards the home city. So in Bochnia we have to use two UHF antennas (Krakow + Tarnow), and one VHF antenna (Krakow).
3. Angle distances among the transmitters. When signals come from several transmitters (at different locations), there is probability that they can be received with smaller number of antennas than the number of locations. To achieve such saving we should make use of characteristics of typical directional antenna - its half-power angle is ca 15 deg. So if the angle distance between two transmitters is within 15 degrees, the signals can be received with one antenna.
Example 2
Olesnica near Wroclaw. Reception from Wroclaw. In spite of three transmitters, we may take advantage of close angle distance. Only two antennas (VHF and UHF) will do the job properly.
Olesnica near Wroclaw. Reception from Wroclaw. In spite of three transmitters, we may take advantage of close angle distance. Only two antennas (VHF and UHF) will do the job properly.
Wroclaw | TVP1 | TVP2 | Polsat | TVN | TV4 | Puls | TVP3 |
|---|---|---|---|---|---|---|---|
| Channel | 12 | 25 | 59 | 56 | 31 | 42 | 42 |
| Power | high | high | high | medium | medium | high | high |
| Polarization | H | H | H | H | H | H | H |
| Transm. antenna | omnidirect. | omnidirect. | omnidirect. | directional | omnidirect. | omnidirect. | omnidirect. |
| Transmitter's location | Mt. Sleza | Mt. Sleza | Mt. Sleza | Zorawina | Wroclaw | Mt. Sleza | Mt. Sleza |
List of transmitters in/near Wroclaw
Example 3
Siechnice near Wroclaw. It will be rather possible to receive signals from Zorawina and Sleza with the same antenna. But the angle distance between Wroclaw and Mt. Sleza exceeds 15 degrees. So we recommend to use two UHF antennas and one VHF device.
Siechnice near Wroclaw. It will be rather possible to receive signals from Zorawina and Sleza with the same antenna. But the angle distance between Wroclaw and Mt. Sleza exceeds 15 degrees. So we recommend to use two UHF antennas and one VHF device.
4. Output power of the transmitters. The channels are transmitted at different power levels. The same TV tower may broadcast one channel at 300 kW, and another one at 10 kW. It is possible that some channels are ideal, whereas others very poor or practically not available.
Example 4
Lodz. In practice TV Puls is available only up to 5 km from the transmitter (TVN - up to 10 km. We should use two UHF antennas, and one UHF device (with signal equalizer). The weak TVN and PULS have to be amplified; in case of broadband amplifier there may be needed an attenuator for TVP2, TVP1, and Polsat channels.
The best solution is to employ channel amplifiers.
Lodz. In practice TV Puls is available only up to 5 km from the transmitter (TVN - up to 10 km. We should use two UHF antennas, and one UHF device (with signal equalizer). The weak TVN and PULS have to be amplified; in case of broadband amplifier there may be needed an attenuator for TVP2, TVP1, and Polsat channels.
The best solution is to employ channel amplifiers.
| Lodz | TVP1 | TVP2 | Polsat | TVN | TV4 | Puls | TVP3 |
|---|---|---|---|---|---|---|---|
| Channel | 7 | 32 | 49 | 21 | 56 | 59 | 43 |
| Power | high 100 kW | high | high 100 kW | medium 1 kW | medium 10 kW | medium 1 kW | high 100 kW |
| Polarization | H | H | H | H | H | H | H |
| Transm. antenna | omnidirect. | omnidirect. | omnidirect. | ||||
| Transmitter's location | Zygry n. Sieradz | Andrzejewska St | Andrzejewska St | Sienkiewicza St | Andrzejewska St | Andrzejewska St | Andrzejewska St |
List of programs available in Lodz and its surroundigs
5. Directivity of transmitters' antennas. Some antennas have directional characteristics. When outside a town/city, they usually are directed towards the town/city. This solution allows to optimize covering of highly populated areas, as well as to minimize interferences among signals from other transmitters.
Example 5.
The TVN transmitter Kosztowy (Silesia province) working in 32 channel does not cover south direction. So there are big problems with receiving this channel in Tychy (not so far from Kosztowy), whereas it is available even in the west part of Krakow.
The TVN transmitter Kosztowy (Silesia province) working in 32 channel does not cover south direction. So there are big problems with receiving this channel in Tychy (not so far from Kosztowy), whereas it is available even in the west part of Krakow.
6. Polarization. There are some transmitters in Poland that use vertical polarization. In this case the receiving antennas have to be mounted the same way i.e. with directors and reflectors arranged vertically. Vertical polarization is sometimes used by low-power transmitters that locally complement the transmission network. Due to opposite polarization they do not interfere with other transmitters.
Example 6
Bilgoraj, the transmitter Tarnawatka. The TVP1 channel is transmitted in channel 10 with vertical polarization, thus we have to mount VHF antenna so that its elements are arranged vertically.
Bilgoraj, the transmitter Tarnawatka. The TVP1 channel is transmitted in channel 10 with vertical polarization, thus we have to mount VHF antenna so that its elements are arranged vertically.
7. Obstacles between transmitting and receiving antenna. It happens that the transmitting antenna is screened by an object e.g. mount, hill, high building. It is the reason why reception is impossible, even though the distance from the transmitter is quite short.
Examle 7
Skawina, near Krakow. The reception from Chorogwica (main transmitting tower for Krakow) is practically impossible. In such difficult situation the customer should look for the help of local installer who will probably be able to find satisfactory solution.
Skawina, near Krakow. The reception from Chorogwica (main transmitting tower for Krakow) is practically impossible. In such difficult situation the customer should look for the help of local installer who will probably be able to find satisfactory solution.
VIII. Kind of installation. We should remember that signal quality deteriorates after each next stage of distribution (worse S/N ratio). It means that in case of larger installations we should use better antennas.
Example 8
Selection of antennas depending on the kind of installation (up to 20 km from the transmitter).
Selection of antennas depending on the kind of installation (up to 20 km from the transmitter).
|
| 1 TV receiver | Community installation | Small multiswitch installation | Large multiswitch installation |
|---|---|---|---|---|
| Broadband antenna (planar) | YES | NO | NO | NO |
| Logarithmic antenna A4011 | YES | NO | NO | NO |
| Antenna set | YES | YES | YES | NO |
| Antenna set A1116+A2682 or A3710 | YES | YES | YES | YES |
Selection of antennas depending on the kind of installation.
9. Influence of interferences, including unwanted signals from other transmitters. When we want to receive signals from several directions we should be prepared for the case of adjacent channels. Reception of such channels will be possible if they do not differ in level more than 3dB. Otherwise, the stronger channel will jam the weaker one.
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