Posts by SV1BDS

    Hi,

    Even OCXO is temperature affected!!! When I build Lars GPSDO and use modified code by PA3FYM when I open or close the air condition it was loosing lock and the code was modified in order to handle such changes. This GPSDO was compared to Cesium and a drift of +-2 Hz at 10 GHz was noticed. It is not perfect but such a stability is more than enough for QO100.

    Hi,

    DB2OS is spread spectrum can be operated at NB or/and WB ? Is definitely not or it is a matter of discussion?

    My thought is that with GNURADIO and GPSDO Pluto, old hardware solution US expirements described in ARRL publications, can now be software iplemented. At QO100, development can be done 'easy' as the received signal can be monitored.

    pe1hzg I am happy that it it was useful to you !!! 0 is my highest power. All the project is experimental, not fully calibrated. It is a try to see it in practice. The biggest personal challenge is that my station operated 25% duty cycle at 43 Celsius roof (environment) temperature !!! ... it still working ...

    Well, i can tell that i hear level 24 , even 27, but only that it is there, just a bit over the noise. If i was meant to understand level 24, i would fail. So I voted 21.

    So to really determine how deep you can hear in the noise, random words do the trick. 73, martin

    I vote 18 but 21 is Q3 ...

    Results of the ZRO beacon test, I submitted 18 but want to remark that not all pulses are sent at a predictable strength, for a next test maybe try a 1000 tone and ask people how many tones they heard?

    Hi Ernst,

    You are my mind ! The WAV files have been normalized but I have thought that a more accurate test will be to say the level and then a tone or CW Vs for example is transmitted. Update: for award some unknown ham radio words can be transmitted for example.

    Hi,


    In order to measure each user, its Rx sensitivity, without any instruments, numbers is transmitted as voice from 0 to 30, each one with a variable attenuation equal to the number transmitted. So a bigger number possible to be read, is mean a more sensitive Rx system exists.

    The test is to be transmitted at Sunday 27/6/21 from 05:00-17:00 UTC at 10.489.940. It consists from a Voice ID and 0-30 level transmission in 3 dB steps, repeated 3 times and then a final voice ID is to be send. Each sequence will start every 10 minutes and holds about 2:25 minutes.


    A vote exists to compare the results.

    Hi,

    A common QO100 NB user question is: what my Rx sensitivity? What is the minimum signal I can receive? This is not always easy to be measured. This need has to cover this test.

    The approach is to transmit numbers as voice 0 to 30, each one with a variable attenuation equal to the number transmitted. So a bigger number possible to be read, is mean a more sensitive Rx system exists.

    Also every one is happy with its system. But it could be very useful for all of us to compare our Rx sensitivity with others. So a Vote will be opened to get relative results.

    The test is planned to be transmitted at Sunday 27/6/21 from 05:00-17:00 UTC at 10.489.940. It consists from a Voice ID and 0-30 level transmissions (update) in 3 dB steps, repeated 3 times and then a final voice ID is to be send. Each sequence will start every 10 minutes and holds about (update) 2:25 minutes.

    DB2OS is there any objection to operate the voice beacon at 27/6 from 5:00 UTC to 17:00 for example and open a vote that users can enter the maximum number entered, in order to have a comparison of received sensitivity? Each Tx holds 1-2 min. Repetition details can determined. If this service is to be included in the QO100 services any personal help is available.

    Hi,

    A user service for the NB seems feasible to be done that will transmit audio files that will contain the Tx dB level (if calibrated can be how dB is down from the beacons ). This will be useful for someone to test his Rx sensitivity. A similar approach has been discussed before using CW. It can be implemented using GNURadio.

    Hi,

    I am not absolutely sure about your point.

    So I will try. I believe that QO100 gives new ways of consindering ham radio communication. In early ham radio HF days Tx and Rx rigs was separated. This is similar to having a separate uplink and downlink in QO100. But it is operational. Later HF transceivers had large VFO drifting relative to modern ones. But stable design permits now narow data modes. The most HF operators here compare QO100 to a VHF repeater. My point is there a nice bird in the sky. We use it just as a SSB repeater? Ham radio is just a free channel? Now a child can communicate with his phone along the world. What is our added value to today communication world community? A few Hertz's in stability? We have a gift in the sky. How we use it to give back to world community that gives us the frequencies?