G7III Experimental Time Station

  • Hi Folks,

    Having finally got around to wiring it all up, I have built an experimental time station built around a MKU-LO-8-13 from Kuhne (to generate the signal) , and a Beaglebone Green SBC (to control PTT and C&C for any required frequency changes etc)

    The MKU-LO-8-13 is locked to the same GPS house reference as the rest of my station. The Beaglebone Green is fed a PPS (Pulse Per Second) from the same house standard (which is aligned to the start of the UTC second) to one of it's real-time units. That real time unit, then keys the transmitter for 100msec.

    It will be on-air, when I am:

    o I am testing

    o Developing modulations such as MSF, DCF, TDF, IRIG etc to provide a Time of Day signal, not just a 100ms PPS

    o Developing the ground software to measure the round trip delay

    It is currently on 2400.060MHz uplink (10489.560 downlink, just inside the CW portion of the bandplan, although that can be adjusted if needed.

    Reports will be gratefully received, however it is very narrow, and very weak, but you can hear it using the Goonhilly downlink. I am hoping to provide gnuradio flowgraphs that may be able to be used for 'one way ranging' of the spacecraft, as well as to set your own clock (once I get those bits written - Tonight was about getting the hardware working and the keying working correctly!)

    Rumours of a paper or a presentation at the AMSAT-UK colloquium can not be confirmed or denied, until I get some interesting results :)



  • DK2ZF: Things are being worked on :) [RWM style, in assembler, along with other code :)]. Although how to embed a callsign in an MSF or DCF time-code is another question :)

    Or maybe a parallel carrier a hundred, or even just tens of Hertz away, as SDR Filters are so good these days

    Oddly enough here in G land, they changed the regs so that rather than saying you have to identify after a specific amount of time, they now say 'when convenient ' or some such phrase, such that it actually isn't a legal requirement to identify every 15 minutes as it used to be.

    My uplink antenna is only an 11dBi flat panel, and running a couple of Wifi boosters (4W followed by an 8W, although I have my doubts the 8W is truely 8W), but interesting I'm 3dB above the transponder with you, that's interesting.

    And indeed, two way QSO's are certainly not off the table, Just I have an interest in timing and ranging, and QO-100 give us such a platform for experimentation :)