Posts by om0aao

    I0LYL Nice work!


    I was thinking what choice will be better:

    1, XVRT near the antenna on the roof

    2, XVRT + PA in the shack


    Good idea and clean construction. CU in the burd!

    Thanks, Achim DH2VA ! But I am afraid that I am not very far from the real. I use signal strengh window which is showing maybe each second avg.signal strenght. First I tune on the beacon frequency, then few kHz away in free space.


    I have second LNB (uknown) so maybe I can try it with it. I think there can be difference, too.

    Thanks to everybody for a lot informations!


    I agree with g7iii that the WX can ruined signals. Both on downlink and uplink.


    Found that most stations use power 1 to 4 watts (30 to 36 dBm) and similar antennas but... the signals on the downlink varies more than 6 dB. That means some stations loose decibels somewhere.


    My question is if my station is working properly (NOT) and how weak signals I can receive.


    Now I can receive 1dB over the noise floor station with 24dB antenna and 25mW or 10dB antenna and 0,63W. As said G7iii - in ideal conditions.


    I will make more tests and try to make a small research... TNX!

    I am trying to calculate the pathloss and sensitivity of QO-100 transponder. Calculation:


    Au = 20 x ( - 4.622 - log f - log L)


    Au - pathloss in dB

    f - frequency in GHz

    L - distance in km


    My calclation shows that the pathloss is around -192 dB.


    My own carrier with 33dBm (2W) with 24dBi antenna is 20 dB over my noise floor. I am receiving with 80cm, LNB and SDR dongle. But I know that there are stations with better receiving conditions.


    My receiving floor:

    -192 dB + 33dBm + 24dBi + 20dB = -115dBm (0,4uV/50 ohm)


    But I don't know what's the gain of receiving antenna of QO-100. Did anybody knows that? And are my calculations right?


    What's Yours receiving floor?

    DB6QS


    Using not modified LNB (PLL-type) with a SDR-dongle 0,5ppm. After 10 minutes warm-up it is very usable for SSB.


    There notable drift during outside temparature change. Especially when clouds moves around the sun it can bee courious. But still workable.


    I have tried software compesation with SDR Console 3.07 https://www.sdr-radio.com/Console/EsHail2 and seems to be good idea. I am running Atom n270 with 1GB and that's not enough, so sometimes I hear cracks in the output sound. But with better machine You can probably obtain good results.

    I am using it too. The pattern seems to be clear. I have pointed it very accurate with a SDR receiver.


    With 2W seems to be good enough for CW. For SSB is usable but I miss some decibels to be pretty good readable.


    I am afraid also that the patch cable is RG-213 type, so the lossy one.


    If somebody would like to be strongh enough for SSB, needs around 8-10W with this type of antenna or try other one.


    https://om0a.cq.sk/en/amatersk…qo-100-es-hail-2-satelit/