House antenna
A house antenna or roof antenna is an antenna for receiving terrestrially broadcast radio and television programs , which is mounted on the roof of the house or in a similarly exposed location and can often be used jointly with the help of antenna amplifiers and distributors.
This is also commonly associated with the home antenna terrestrial television meant by the distribution of the signals to the junction box in the home, that is, the entire G emeinschafts a ntennenanlage (GA). A large community antenna system can supply a few hundred antenna connections in a hotel or in several apartment blocks .
A house antenna usually consists of at least two antennas attached to a metal mast on top of each other. Separate antennas are required for the frequency ranges ( VHF and UHF ). To receive television signals, Yagi antennas are used, which are aimed at the respective transmitter location .
The antenna types used for radio broadcasting in the VHF range can vary. With a dipole antenna , reception is limited to the most powerful radio frequencies in the area, while a yagi antenna can be used to locate a certain transmitter location, which may be far away.
If there were transmitters in one direction, only one TV antenna was sufficient if all programs were broadcast in the UHF range. This was z. B. the case in Cuxhaven, since the NDR station in Altenwalde also broadcast ZDF and N3 as well as later Sat 1. However, the RTL program was broadcast on VHF channel 11, so that a second antenna was required here.
For DVB-T , digital terrestrial reception, the previous antennas can usually be used. A realignment may be necessary, as the broadcasting takes place via a significantly reduced number of television converters and filler channels compared to analog television. Depending on the polarization , the antenna may have to be rotated 90 degrees in the longitudinal axis. The two antennas shown in the photo are horizontally polarized. For example, DVB-T is horizontally polarized in the SWR transmission area, but vertically polarized in the Rhine-Main area and Saarland.
One sees the roof antenna less and less alone on house roofs, as it is increasingly combined with the " satellite dish " or gives way to cable television . A satellite broadcast reception system can be integrated into an existing community antenna system after channel preparation. However, the program offer is limited and a separate converter is required for each analog radio and television channel. If the cables are suitable for the high-frequency satellite signals, the existing cabling can often continue to be used in a single-cable system or unicable system. In single-family houses and small residential units, the so-called satellite block distribution using multi-switches is often used as a relatively simple, technically flexible solution for individual satellite reception and local antenna reception.
Many of the large community antenna systems (GGA) that were built up until the 1980s have been connected to the cable television network and are now operated as cable television .
literature
- Jürgen Tech: Do-it-yourself antennas. 2nd edition, cheek-Verlag GmbH + Co Druck KG, Stuttgart, 1980, ISBN 3-7724-0301-8
- Herbert Zwaraber: Practical setup and testing of antenna systems. 9th edition, Dr. Alfred Hüthig Verlag, Heidelberg, 1989, ISBN 3-7785-1807-0