2020 - This 19" case is home for three different components: a commercial GPS disciplined 10MHz oscillator and the antenna switch which is described elsewhere on this web site. Last not least I was lucky to acquire the last direct sampling HiqSDR transceiver featuring 14-bit resolution, manufactured by DB1CC. A fantastic design by N2ADR who also wrote the Quisk software which runs on my Linux machines.
No workshop without a standard frequency and accurate time generator! My first attempt in this area was a receiver for the DCF77, the official German time code transmitter at 77,5kHz. I built the recommended active antenna and placed it in the attic of my house:
Indispensable was a sharp 77.5kHz quartz filter, here is my realization:
Searching the net for a suitable time decoding circuit I found an interesting design by a small British company
"Marvellconsultants" .
They were kind enough to send me an empty PCB which was easy to populate. Next to the code the unit
also generates accurate squarewaves of 1Hz and 10Hz.
In principle this setup performed very well, but unfortunately even in my tiny village the power line brought enormous noise into the house and antennas. Especially troublesome were two broadband signals at mostly 80kHz and 81kHz. Adding insult to injury their frequency was very unstable and thus at times even covered and practically ruined the DCF77 signal.
It was with a heavy heart that I replaced the DCF77 unit with a commercial GPS receiver. I added a large LCD display to show the satellite data which are decoded by a "QRP-Labs" unit:
The GPS unit delivers accurate 1sec pulses and the NMEA data stream:
The "Lady Heather" software visualizes the NMEA information:
The GPS disciplined 10MHz output:
