5 Mounting the Antenna
The antenna has to be aligned horizontally in longitudinal direction to the transmitter, i.e. in direction to
Mainflingen near Frankfurt / Main in case of DCF77, or in direction to the location of the MSF or WWVB
receiver accordingly.
If the antenna is not aligned properly then signal reception is degraded, which can result in a limited time
accuracy. The antenna should be installed with a minimum distance of 30 cm away from all metal objects and
possibly any microcomputers and electrical devices (engines, electricity, etc.). A distance of several meters from
TV and computer monitors should be considered as well.
The best method to align a longwave antenna is to turn the antenna slowly until the monitored signal level
is minimized, and then turn the antenna by 90
o
to achieve maximum reception. However, a high signal level
alone is not a guarantee for good reception since it can even be caused by electrical noise in the associated
frequency range. For standard longwave receivers it is important that the modulation mark is blinking exactly
once per second, without intermediate flickering.
DCF77/PZF receivers use correlation techniques to decode the phase modulation provided by DCF77, and
with these types of receiver the maximum interference immunity can be found by looking at the autocorrelation
parameter displayed in the display menu "PZF-STATE". The displayed value should be as close as possible to
100 % for best reception.
WARNING!
Antenna mounting without effective anti-fall protection
Danger to life due to fall!
- Pay attention to effective working safety when installing antennas!
- Never work without an effective anti-fall equipment!
WARNING!
Working on the antenna system during thunderstorms
Danger to life due to electrical shock!
- Do not carry out any work on the antenna system or the antenna cable
if there is a risk of a lightning strike.
- Do not carry out any work on the antenna system if the safety distance
to free lines and sequential circuits is exceeded.
IMS - LANTIME M1000
Date: 2nd July 2020
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