Posts by g7iii

  • Digital Tests on NB Transponder

    @db6rs: That will depend on the mode. People have already managed to get 100mW-200mW to work on CW, 500mW on SSB. Considering SSB requires ~6db more, that fits within the ball park.


    For a first *guestimate* take how much less S/N your chosen digital mode needs over CW, and calculate from that, that should give a good idea.


    However, you must take into account the antenna used. The 100-200mW CW station was using a 50x60m dish. the 500mW SSB station had a 1.2M dish


    Also, we don't know exactly what will happen when more folks start to use the transponder, figures may change if it gets very busy, It will be fun finding out...

  • "Engineering Announcements" (UK IBA History)

    pe1chl: Oh wow! "Inverted Sideband" I'm guessing that was the ROT13 of it's day (IE absolutely useless) ? During these times in the UK, the independents (ie *NOT* the BBC [aka 2LO once upon a time when they where 'amateur'!] were just starting, and very regulated


    I'm sure google has some of the test cards that you probably received! I say resurrect something similar!


    73s


    Iain

  • "Engineering Announcements" (UK IBA History)

    Well, this thread is probably going to end up as technically useful as the Sat Humour thread, and maybe no-one out side of the UK will recognise the image or the joke, but,I have heard it suggested to use Wednesdays UTC as an 'Experimenters Day'.


    Well in any case, any G's, M's, or 2E's recognise the attachment ? :) Or at least something similar ? Do you remember the Engineering Announcements aka Ghost Programmes ? I was thinking of adding PID information for what I'm playing with on any particular Wednesday. Anyone up for generating something similar (Along with Testcards..) ?

  • Qatar-OSCAR 100 (QO-100)

    Hi Peter,


    Congratulations to you, AMSAT-DL, QARS, and Es'hailSat. Very appropriate considering the giant leap (Pun intended) in capability this spacecraft will bring to the Amateur community. Thank goodness NEXUS (FO-99) worked :)


    73s


    Iain

    (who must go and order the remaining uplink bits!, minor issue of an antenna to fix, the 30W PA needs something to dump it's power into, and a dummy load won't do!)

  • RTL-SDR

    G4SAQ: Not sure about the transponder itself, but I think there will be ~240ms RTT simply due to Geostationary orbit to consider.

  • NB Station for Es'hail-2

    So long as you can receive one or other beacon within the passband (and it's CW), a single stick software drift connection is possible. I have some gnuradio code that does just that (although I'm using my Ettus USRPs, but the same code could be used with a dongle


    Whether a tablet would appreciate the extra overhead of gnuradio is another matter of course.


    For those interested, Basically I take 250k of B/W, Filter and Decimate around the 'beacon', then send to a FFT, measure the 'strongest' bin, calculate what that frequency is, compare against the 'correct' frequency, and send the difference back to the USRP or Frequency Translating FIR Filter (otherwise known as the Virtual Big Tuning Knob!)


    In the case of a dongle, it would need to be the FIR Filter, as the drivers in gnuradio don't let you change the frequency of the device once set without stopping and restarting the flowgraph.


    Note, my code will go down to 250mHz (Yes, milliHertz). Overkill, yes (although not for some of the experiments I intend to do), but remember that when the beacon is in PSK mode, there will of course be frequency shifts every time the phase changes to deal with. I'm hoping at least one beacon will always be in CW mode


    Iain

  • Es'hail-2 beacon frequency (non-amateur)

    Mark,


    I've not seen the 11205 beacon here in G-Land for a while (It is believed that they may have switched to a narrower beam a week or two ago). However, during the time they switched, and afterwards, I could see an increase in the noise floor while they were testing the NB and WB P4A Transponders.


    The fact that you can receive beacons of _something_ suggests your system is good-to-go (pointing adjustments with a 2.2M dish aside, you may need to tweak things, I know I will, and I only have a 1.1M)


    I think we just have to be patient now, for the spacecraft to be handed over to the operators, and then some time after that P4A testing will begin. I'm sure Peter and Achim will keep us updated as and when there is something to tell



    73s


    Iain

  • 20W WiFi Booster module for 2.4 GHz

    Curiously they don't ship to the US either. I'm guessing maybe HM Customs is getting hot on High Powered 'illegal' Wifi gear or some such at the moment. But yeah, it should be the same (at the moment, After March 29th who knows but we won't discuss THAT here!)

  • NB passband monitoring

    VU2UUU,


    Transmissions appear to be over for today. H/V switching is done by sending +18V (H) or +12V (V) via your bias T or other method (A Dual output LNB has it's advantages when you connect one to a DVB-S(2) PCI card and set it via DVB software. I'm not aware it can be done via SDR Sharpe.


    If you can't change the voltage, you can twist the LNB 90 degrees manually - that should do the same thing.


    Activity seemed to finish around 1430 zulu today and yesterday.



    Iain

  • 2,4GHz transmission check

    DB8TF: The N200 was purchased a number of years ago when the exchange rate was far far kinder to us here in the UK [We won't talk about all the reasons it isn't now...], the USRP2 turned up second hand, as did the extra SBX, at a very good price, so I grabbed both of them as soon as I could, realising that there was great potential for experimentation with Es'hail-2/P4A :)

  • 2,4GHz transmission check

    I will have an extra SDR (USRP2 w/SBX board) available. I will either listen to my uplink signal locally over the air, or use a Hybrid Coupler (and if needed attenuator) and feed it into the RX2 port of the SBX. [I am planning on being able to combine multiple uplink signals for various experiments/reasons]


    TX/RX port on this particular SBX will be an Aux uplink (possibly FT8), while the existing N200 w/SBX will have Primary narrowband uplink and downlink.


    The USRP2 and N200 will be phase locked via a MIMO cable, thus enabling ranging and timing experiments



    73s


    Iain

  • NB passband monitoring

    Peter,


    I could not agree more that it isn't funny. As you say, someone has the required skills, but lacking in patience, not to mention the respect to Es'hailSat, MELCO, QARS, AMSAT-DL, and all of us that are honouring the request not to transmit


    It is a shame that 'There is always one' that spoils it for the majority. Frankly I'm having way too much fun just monitoring the downlink and tweaking the dish and LNB based on the transponder noise!


    Could I suggest that we all do what is advised with similar issues on terrestrial repeaters, and ignore them ? Record them by all means to try and fingerprint/identify them, but don't give them the oxygen of publicity when we hear them on here on any other public forum



    Iain

  • 3cm Kuhne transverter

    Thanks both! I think I am coming round to building a second earth station. Since my Dishes aren't quite the size of those at Goonhilly, rather than name them Arthur and Guinevere, I'm thinking of Merlin and Morgane (SG1 Reference)


    This Es'hail 2 / P4A stuff is way too much fun already!

  • Es'hail-2 beacon frequency (non-amateur)

    More likely a multiple of 10MHz and/or 25MHz within your system (LNB may use 25MHz). Correct frequencies are 10706 and 11205 MHz for the Engineering beacon.


    You can confirm by:

    o Moving Dish

    o Switching Polarisation

    o Putting your hand in front of the LNB


    If they don't change, then they are local to you



    Iain