How Can I Diagnose and Eliminate DCF77 Reception Interference?

Your DCF77, MSF, WWVB, or PZF receiver-equipped system might indicate reception interference via the LEDs on the receiver or via status messages in the Web Interface, and there are various possible reasons for this.

If your DCF77 receiver is displaying error messages such as "Antenna Faulty" or "Time Sync Error", the first thing you should do is check the reception quality of your DCF77 antenna. Interference can be caused by dirt on the antenna, by defective antenna cables, or if the antenna is not properly aligned. It is also possible that changes to the reception conditions at the antenna location have made it impossible to receive the signal without interference. Your DCF77 antenna must be directed towards the DCF transmitter in Mainflingen, near Frankfurt am Main. The antenna should ideally be installed in a location away from metallic objects, electrical lines, TVs, or computer monitors if possible, which is why we recommend installing it outside of your building.

Reception quality can be tested using the following methods:

Using the status LEDs on the receiver
If the "free run" LED (FR) is off, this indicates that the receiver has been successfully synchronized. Conversely, if the "free run" LED goes back on at the start of the next minute, this is indicative of reception problems. A clock that has been in free-run mode for more than 12 hours is indicated by the "free run" LED flashing.
Using the Web Interface on LANTIME NTP servers with a PZF, MSF, or WWVB receiver
Select the menu "System -> System Information -> Show Receiver Information" in the Web Interface. The "Correlation" and "Field" values are the key factors in determining signal quality. The correlation factor percentage displayed should be as close to 99% as possible.
Using the display on the receiver itself
Use the function and arrow keys to select "Reference Time -> Info PZF -> Correlation & Field" on the display.

If you are experiencing problems with reception on your DCF77 receiver, you can also refer to the website dcf77logs.de to find out whether there are more general problems with DCF77 reception. This website provides access to all log files and also offers a summary of any special events such as leap seconds, disturbances, daylight saving time adjustments, etc. Please note that the website is only in German.

Of course, our Technical Support team is also on hand to assist you at any time. If you are experiencing reception problems with your PZF receiver-equipped LANTIME NTP server, please create a diagnostic file for the system in question via its Web Interface if possible. This file can be analyzed by our team to resolve your problem as quickly as possible.

Systems with Long Wave Reception

DCF77 Radio-Controlled Clock for Universal Serial Bus (USB) Interface