Posts by dg0opk

    Hallo everyone....

    i made a short PROMOTION VIDEO for QO-100 (retransmitting NB TP via WB TP in DATV H265)

    the testing setup by dg0opk was 120cmDishes on RX/TX has given me the time and possibilty to transmit all live you can see... in DATV H265 1280x720!!

    VIDEO is on on YOUTUBE ....

    120cm RX and TX for WB and NB TP use...

    some more information is given in the info...of the YT video

    many thanks to all (especially to background workers in AMSAT-DL to make it possible...)

    73 de Michael DG0OPK

    Hallo everyone....

    in the picture attached you can see the difference in performance of the old Conner Winfield D75F (2017 and before - upper part of picture) and the D75F oscillators are delivered after around mid/end of 2017 and later (lower part) ....

    Measurement was done in MAY2019 on a 35cm DISH with the QO-100 lower BEACON as reference...

    So i think that are no questions about anymore and i can confirm all the result from David G0MRF...

    I am happy that i got some old ones in 2017 for my OTSLO LNBs and found a replacement source for future (but much more expensive)

    73 de Michael dg0opk

    Hallo ....

    after upgrading to VARA Modem 3.1.1 and a new (faster computer) i got the following results on a first test with my (non GPS locked setup)

    Data Sent: 102384Bytes

    Time: 8min40

    Thruput: 11768Bytes/min

    looks ok for an SSB channel.... with 3kHz BW ....(nice!)

    Peak Datarate: 3500bps

    setup using:

    TCXO LNB with software driftcorrection on QO-100 BEACON (SDRConsole), ADALM PLUTO (TCXO MOD) in FULLDUPLEXMODE, SDR Console3.0.11 ,VirtualAudio to Vara Modem, RX/TX Switch ... VOX Controlled by SDRConsole

    73 de dg0opk

    @ PA3FYM

    stability can maybe corrected (if needed) via software tools ....

    phase noise is build inside the oscillator....AND

    the right LNB is to use withthe GOOD CHIPs for low NOISE ...

    maybe the RDA chip in the old octagons or other LNBs

    so the RX results will maybe very good...

    73 de dg0opk

    Hallo ...

    i got some measurement result for the alternative 27MHz TCXOs

    DRIFT (ppm) attached.... phase noise is good

    if anyone need .... as replacement for the "bad D75F" delivered after mid of 2017...let me know...


    PLEASE ASK THE RESELLERS ... about the BAD D75F not me (i have some old ones for personal use which working very nice)

    have the resellers verified their products they sell with the given information on my homepage in april 2017 ??

    please ask again ... to me directly if you need an good working and stable LNB for QO-100

    73 de michael dg0opk


    good news about SDR ANGEL ... from 18july2019

    experimental DVB-S2 support!


    DATV demod: experimental DVB-S2 support

    DVB-S2 standard support using the "work" branch of leansdr ( supposedly still experimental. This works reasonably well though. You may need to move the controls a bit to get a lock.

    i have found today ..but not tested .. very...interesting if it works

    73 de Michael dg0opk

    Hallo ...

    after some time ....the CAT is out of the BAG ...

    the D75F dont work anymore like before ...

    the old ones from 2017 are GREAT ...

    but i have a new source for 27MHz TCXOs with good quality...they are in test now...

    please mail me if you have interest (but they are more expensive but ok)


    73 de michael


    hallo robert ... the differences between bad and good weather are not very much ...

    so you have an loss or inaccurary of maybe +-0.3dB ...if the dish is correct aligned..

    maybe some times in the summer we have some thunderstorm with rainscatter...

    but thats an on other game to play... HI

    73 de dg0opk


    i made some tests to receive the WB Transponder on small dishes to compare maybe with others.... please give information about your results...!!

    The tests were done last 6weeks with my modified TCXO-LNBs
    (Octagon OTSLO, AX Black Buster) with LO 9388 and LO9750MHz

    I got the following levels (MER ) results on the WB beacon ... measured with TT-S2 1600 or MiniTiounerExpress



    60cm NO NAME DISH 5.2-5.5dB

    60cm Kathrein Dish 6.1dB

    85cm FUBA DISH with LNB Offset 7deg 7.2dB (Center to 19.2east)

    85cm TRIAX OFFSET 8.3dB

    120cm LAMINAS OFFSET 9.4dB


    the MER is about + 0.5-0.8dB more if you use an (good!) TCXO instead the original crystal inside the PLL LNB.


    the MER was measured during an "empty tranponder that means only the beacon" without other stations are qrv...because the MER of the beacon depends sometimes on the activity on the higher part of the passband...

    73 de Michael dg0opk


    Hi Richard...

    i have also orderd ... but no time to test it the moment... maybe a good next step is to cut the stripline on the output combiner and put in a 50Ohm load .... then more tests can be done?


    the anaren combiners are specified until 2.3GHz so may be some little more loss on 2.4... and the transitor datasheet looks not so bad... max output >150W at 32V P1dB (2.14GHz Page 8 of dataheet), S parameters are given until 2.2GHz and they look flat... maybe it is usable at 2.4G... i hope for that ....if not ...then maybe a good one for 2.32G contesting...

    so lets see ..

    73 de dg0opk


    Hallo... any question or note about the MRF7S21110HS board...

    i can not see any 50R resistor on the output combiner..maybe it is missing on the PCB and has to soldered on the open end of the stripline? Or maybe the stripline and the capacitor is used as the LOAD @ 2.2GHz?

    Michael dg0opk

    Hallo Peter...

    interesting to see this....

    thats nearly the same antenne i used in 2001 for AO-40 downlink on my portable setup for receiving the s-band...

    now tested on QO-100 uplink again and found it as the best working setup with lowest money... versus other possible antennas/feed solutions.

    I use a 3 turn helix as feed like seen on the picture.... many thanks for posting this information.:)

    73 de Michael dg0opk


    you need a clean and stable tx signal to decode FT8 .... this is very narrowband mode....

    so on RX LNB with low noise TCXO and/or SW correction (better both to use) or GPS locked with low JITTER and LOW NOISE is recommended ... (that is difficult) for a low budget... station

    on TX Side you have to use the same ... TX with tcxo on all components or GPS locked...

    i am freerunning on all my systems with TCXO inside in moment GPS lock is possible (and it is much work to modify all components ) and GPS is not installed until now....!

    73 de dg0opk

    NOTE the DELAY of SPOTTING is ABOUT 5mins... so be slow if you use different setups for testing ...

    @ PA1SDB is 1dB at 20.april 2019 20.33ut so same margin of 15 or more dB?

    i dont know....

    73 & GN

    Hallo ...

    for testing purposes i put on an FT8 Monitor on QO-100 to 10489.600 to spot to PSK31reporter.

    Because it is not possible until now to direct spot on 3cm i used 23cm 1296.6 MHz instead.

    rx results on QO-100 can be seen here ... (last 12hours)…band=480000000-1400000000

    RX setup:

    85cm TVDISH (3LNB 13/19,2 and 26 east) OCTAGON OTSLO(TCXO) + ADALM PLUTO (TCXO) or RTL-SDR(TCXO) , WSJTX 2.01

    have an nice EASTER TIME

    73 de Michael dg0opk



    because of the QO-100 activity now I found more and more of "resellers" with some dubios work and thats why it is needed to put a warning on my homepage... !!!

    MAYBE IT IS NOT A GOOD STYLE .. NOT TO GIVE THE SOURCE OF THERE INFORMATIONS AND DESIGNS and maybe they should put some serious measurement results if they have REALLY verified there work...???

    I have DONE.... and the references to G0MRF and ZS6BTE are written inside the article and all is OPEN for PRIVATE USE (HAMRADIO) and not for COMMERCIAL PURPOSES!

    THANKS de Michael dg0opk


    i got an similar model today...…a66b7f:g:WyQAAOSwg31ahPWo

    2 x RDA3565S , one crystal (27MHz??) maybe below the PCB... no seen if open...

    GOOD RECEPTION on 26 EAST BADR4 11996 > 9dB ...a bit more sig then the OTSLO 1208/1301

    look nice at first sight...


    Testet the unmodified LNB on 10492 H (ES Hail2) ,11196 H and 12168V (BADR4)

    nice signal levels on my 85cm Dish... 0.2-0.4dB better then the old OTSLO 1208/1301

    OK for the MONEY...!

    73 de dg0opk