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4417, 4420 , 4437 DCF77 GPS active directional antennas
DCF77 4417 / 4418 / 4420 / 4436 / 4437 antennas are all German hopf antennas with active directional capability and an electrical design. Ferrite antennas are used for long wave range frequencies to keep the antennas small. The oscillating circuit in the antenna, which is made of a wire ferrite rod and various capacitors, is set up on 77.5 kHz. DCF77 is a standard for transmitting time (hours, minutes and seconds) and date to clocks and timing devices, and it is transmitted to devices with high accuracy by radio (local transmitter).
DCF77 Antenna 4417 / 4418 / 4420 / 4436 / 4437
Antenna structure
All hopf antennas are directional active antennas and of the same electrical design. Ferrite antennas are used for the frequencies in the long-wave range to keep the antennas small. The oscillating circuit in the antenna, made of a wired ferrite rod and various capacitors, is tuned to 77.5 kHz.
The features of the oscillating circuit depend mainly on the ferrite rod. Temperature changes influence the permeability of the ferrite rod and thus the mid-frequency of the tuned oscillating circuit for the DCF77 signal.
The output voltage of the oscillating circuit is fed to an amplifier with definite input resistance. Behind the amplifier there is an adaptation to the antenna cable.
Types of antennas
The following types of antennas for the different purposes are available:
FG443600 Indoor antenna
FG441700A Outdoor antenna for the flat roof installation
FG441800A Outdoor antenna for the wall installation
FG442000 Outdoor antenna for the pole installation
FG443700 Outdoor antenna with non-directional reception for mobile operations
Indoor antenna FG443600
This antenna can be used in buildings away from sources of interference for the DCF77-reception. e.g. TVs, monitors, terminals, in-house-LAN, electrical engines etc.
Also the construction of the building has to be taken into consideration. Reinforced concrete buildings and fairing plates attenuate considerably the DCF77-signal and cause a bad signal / noise ratio.
The antenna, which can be turned by 360°, is screwed to a wall bracket made of zinc-coated steel.
Outdoor antennas
Mostly radio controlled clock systems are running with an outdoor antenna. Whereas the surroundings of the indoor antenna can change because of changing technical operations in the rooms, the conditions for the outdoor antenna remain nearly constant.
For rough weather conditions we supply a very robust outdoor antenna. It is housed in a round weatherproof plastic casing. The different antennas differ in their mechanical structure only.
The mechanical construction is made of a sturdy, anodised aluminum or die-cast aluminum designed to withstand strong wind. The antenna cable leaves the casing at the bottom.
DCF77 active antennas
Data sheet content
Time server
- power supplies feature
- single power supply
- Time Server Protocol
- DCF77
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Specifications
Time server | |
|---|---|
| power supplies feature | single power supply |
| Time Server Protocol | DCF77 |
DCF77 4417 / 4418 / 4420 / 4436 / 4437 antennas are all German hopf antennas with active directional capability and an electrical design. Ferrite antennas are used for long wave range frequencies to keep the antennas small. The oscillating circuit in the antenna, which is made of a wire ferrite rod and various capacitors, is set up on 77.5 kHz. DCF77 is a standard for transmitting time (hours, minutes and seconds) and date to clocks and timing devices, and it is transmitted to devices with high accuracy by radio (local transmitter).