Posts by PA3FYM

  • Does it make sense to multiply 10MHz reference?

    Quote from SV1BDS

    Hi,

    Lets suppose that we have two OCXO one in 10 MHz and one in 100 MHz with the same phase noise at the same offset.The phase noise is increased by 20log(N) dB) where N is multiply factor. In our case N=10, so we have 20 times larger noise. It meens in simple words that if we create 10 MHz from 100 MHz it will have 20 time less phase noise or if we create 100 MHz from 10 MHz it will have 20 times larger phase noise. It is obvious that when we produce 25 MHz from 100 MHz the phase noise will be less than produced from 10 MHz. One calculation that I have done is that phase noise produced by multiplying by 390 (9750/25) is about 50 times bigger!!!

    The ECOC-2522-100.000 existis in various versions with similar prices and different ppB, so a small ppB is prefered as has better stability... PA3FYM AOCJY1-100.000MHZ seems a good choise for GPSDO available from Mouser at half the price.

    George, it's 20 dB more / less phase noise. Anyway .. that's exactly why I -from the beginning (end 2018)- beated on the drum concerning PN of the LNB reference and use(d) crystal filters for purification.

  • MY QO100 SETUP

    Hi George,

    That is an interesting 'Way to Rome' and I am surprised that the HC74 can cope with 100 MHz ?


    Where did you get that 100 MHz OCXO?

  • MY QO100 SETUP

    The small loop with marker 1 is the loop you want to try to get into the center of the Smith Chart.

    Try to fiddle with the patch edges/corners and decrease, like G0MJW said, the sweep to 2.3 - 2.5 GHz.


    Your results look nominal, but need some tweaking.

  • What TX amplifier do you plan to use?

    PA5CW Bought them in 2016 on 'the Jutberg flea market' to build my first Es'hail-2 transverter. (Because of that) Others bought them too and I haven't seen them ever since. I got a mail from somebody from Italy a long time ago about how to get the pallet running and mods for 2.4 GHz. So apparently they were available in Italy too . .

  • Remote operation via QO-100

    ON4CJQ It applies to the uplink facility. Remember, (not to you personally) you are working through a facility which is not yours.

    So, the owner (Es'hailSat) decides which users he (it) accepts on his space vehicle.


    It's the same as that you decide who enters your living room at home. Because it's your house.


    There are no technicalities involved , it's the owner who decides, like you in your own house / living room.

  • Remote operation via QO-100

    The satellite operator, in this case Es'hailSat, has the right to define which or what kind of 'operation' they allow on their satellite(s). After all, the satellite is owned by Es'hailSat and not by us. For the QO-100 transponder Es'hailSat delegated governance to AMSAT-DL.


    The reason why the satellite operator has this point of view is simple: reduce failure factors. QO-100 is aboard a commercial/professional space vehicle with other (paying!) users/customers with well defined service level agreements (SLA's).


    Bear in mind that from a professional perspective it is 'odd' that a satellite operator allows 'non coordinated' users on/through their space vehicle!

  • NB passband monitoring

    DK8KW and dg0opk FT8 works exactly the same are on e.g. the shortwave bands. If you can make FT8 QSO's there, you can make them via QO-100 as well. QO-100 does not know or does not react different that/when you are making FT8, it's all up to the uplinker (having a stable enough signal).

  • PROPOSAL FOR INCREASED ACTIVITY

    I reckon more than 1700 POTY's (kits) have been made. So there is potential activity enough. Furthermore there must be an RF incentive (i.e. make stuff for 2.4 GHz narrow band) to become active on the NB transponder. Making stuff for 2.4 GHz uplink seperates boys from men ; -)

  • NB passband monitoring

    I made FT8 QSO's with no issues. When you set your (Windows) time properly with rsNTP (google on it) and you're stable enough, and you have clear audio, it works flawlessly.

  • TRV QO-100 for TRX HF

    SP3OSJ Sorry to post this feedback here, but when I listen to your GPS stabilized RX (see YouTube movie) in relation with the beacon I hear unacceptable drift. It is not a steady tone and I hear too much phase noise (the tone is 'raw' and not clear).