Posts by G0MJW

  • console crashes

    Quote from 2e0saf

    i was at 1.5mhz i have dropped it to 900khz and does seem to be more stable... what pc is recommended for sdr console..?


    i thought it was a i3 cpu with 16gb ddr3 ram its actually a i5 3470 @ 3.2 ghz with 8gb ram and windows 10 pro


    is that not fast enough

    It should be OK, even though it is quite an old CPU from around 2012, without hyper-threading but with 4 cores. Had it been an early i3 with dual cores and limited performance it may have struggled. Especially if you had been looking in a wide bandwidth (some MHz) with a high res screen to update. There should be a CPU and GPU load indication at the bottom of the screen, as long as it's well below 100% you are not limited by CPU.


    Pluto bandwidth rates with USB are not great and console does tend to crash if the connection to the SDR fails on it. USB lead, USB power, all things to check. If its more stable at 900kHz try 750kHz, 550kHz etc. That will help work out what is causing the crashes. There is also a logfile under tools. Another thing that causes crashes is where the Pluto reboots because it detects incorrectly that the power to it has changed. This is very common if you have an external antenna connected which is grounded. There is a mod to fix this.


    Mike

  • MY QO100 SETUP

    Quote from SV1BDS

    PA3FYM Hello Remco, this is my SWR plot of my POTY feeder. I do not see the second null near 2.4 GHz. Any comments ?

    Interesting you don't ask me given I designed it... but anyway looking at the smith chart - it would be better to plot for 2.3-2.5 GHz but I think I can see the dual resonance looking like a ^ rather than a loop. Should be good enough though you have all the tools to get it spot on.


    Mike

  • console crashes

    That's quite a low specification PC. Are you trying to look at a very wide bandwidth?

  • Es'hail 2 Commercial TV Transponder question...

    A good way to line up is the beacon MER on wideband, with no others using the transponder it should be 11-12 dB. For DATV this is what you want optimised and once it is, narrow band will be more than good enough. On Narrow band you need to maximise the beacon amplitude, not the SNR because that dish will see the transponder noise floor well above the background noise and it's hard to tell improvements.

  • QO-100 DXCC and User Statistic

    Quote from HB9SKA

    Yes, correct is the range of our signals via satellite. It's easier to look on QRZ.COM and copy the landline distance. But it's a funny "pseudo competition". :)

    I think it's worse than that as it implies we are ignorant of the real path the signal is taking, like claiming DX when working that DX through your local internet connected repeater. That's not the case for anyone working through QO100 as they will know very well the path because they first had the difficult task to set up the necessary equipment.


    What is challenging here is geometry. That could be a basis for competitive DX distance like records, How low on the horizon can you still access the transponder, or perhaps I should say how far below the horizon as that should be possible too, though not by much, due to refraction. 9V1HY to PR8ZX is very low elevation at both ends, but so would be Greenland to Svalbard even though great circle it's not so far. Iceland to Antarctica would be more moderate DX, with 10 degree elevation but its a very long way by boat. For those of us with relatively high elevations it's who we can work with their lowest elevation, but they are doing practically all the work. At HF, DX often means rarity rather than distance. Who has worked the most countries.

  • QO-100 DXCC and User Statistic

    Why would AMSAT NA have such a competition? Surely all QSOs via geo are more or less the same distance? Earth-satellite-earth. OK with a few 1000km difference on the footprint edges. Measuring the great circle distance is irrelevant as its not taking that route. What might make sense is the QSO closest to the geometric limits.

  • Es'hail 2 Commercial TV Transponder question...

    Best find another receiver. I think it can be re-programmed. You also need to chose the right FTA signal that's actually receivable in the UK. Better way, align on 28.2 then attach your airspy, if necessary via a suitable downconverter, and look for the transponder while moving the dish a tad to the south.

  • PLUTO IMD AT GNURADIO

    As Colin says plus be careful not to over drive your spectrum analyser. This can also cause intermods to appear and is surprisingly easy to do with wideband signals.

  • Wo liegt die RX-Frequenz beim Lime SDR Mini?

    Quote from SWL-Wilfried

    Good Morning all,


    who uses the Lime SDR Mini and can tell me details about the RX frequency? Do I have to use a mirror with LNB or does a correspondingly powerful antenna, such as a

    Wifi grid mirror aluminum 2.4GHz 24 dBi

    For receive you need an LNB and a satellite dish. You will need to power the LNB from a bias-T. Ideally, you want a PLL type as these are more stable. You receive the IF with the Lime and it is usually 9750MHz lower. I will leave you to do the maths.


    You need an LNB and a satellite dish to receive it. You must power the LNB using a Bias-T. Ideally, you want a PLL type because they are more stable. You get the IF with the lime and it is usually 9750 MHz lower. I leave it to you to make the math.

  • UPLINK - PATCH VS HELIX - what's better

    Yes you can add elements. A disc or a loop, of the right size and spacing (that's where it gets tricky). You could even use a lens instead. The question is is it worth it for the amount of gain gained.