1.
Introduction
As of version 0.7, lhpsdr has functions to receive, decode and
display the Date, Time, Summer Time in Effect, Leap Second, DUT1,
Parity Bit status and other data as transmitted by Time and
Frequency Reference stations on VLF frequencies. Currently lhpsdr
can receive such data from the German DCF77 on 77.5kHz, the Russian
RBU on 66.667kHz, the British MSF on 60kHz and the French TDF on
162kHz. With a Ground Plane antenna for the 10 MHz band (7.5m high)
and in good conditions, these stations can be received and decoded
successfully even though they are between 2500km and 3500km away
from my QTH!
The time decoding function is activated by selecting TIME in the Guest Modes popup menu, which opens the Time Stations window for further action. In this window, the Time Station Combo Box allows selection of the Time station, while the Receive toggle button starts the relevant receiving and decoding functions. The Time Stations window has a display for the Date and Time, as well as many indicators for Status decodes and error conditions, depending on the Time Station. Some stations (e.g. RBU and MSF) transmit DUT1 too, while RBU transmits Julian Day and DUT data also. Please note that even in good conditions, it takes a few minutes for lhpsdr to sync with the time station and correctly decode date and time data.
2. Operation
The Time Signal decoder function of Lhpsdr is controlled from the
Lhpsdr Time Stations window. To decode time data from a VLF or LW
station, lhpsdr must be in receive mode. Then the station is
selected from the "Time Station" combo box menu and reception is
started by activating the "Receive" button. It normally takes at
least three to four full minutes for the Time decoder function to
synchronize with the transmitting station and start decoding.
Different time standard stations have different formats and
transmit different time information. Date and time is displayed in
the "Date" and "Time" frames and other relevant information in the
"<Station> Data" frame. Any errors occurring will be
displayed in the "Error Conditions" frame.
Lhpsdr Time Standard decoder has been tested on many occasions and it has been stable and successful. A fair signal level is needed for error free decoding, as an estimate a S/N ratio of about 10 dB.
4. Copying This software package is released under the GNU Public License. Please see the COPYING file for more details.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details: