Posts by dg0opk

    DD4YR

    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

    Hallo....

    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


    MER OF QO-100 DATV BEACON

    ----------------------------------------------


    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


    Note:

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


    Note2:

    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

    M0VKK

    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?


    BTW:

    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

    M0VKK

    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

    Note2:

    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 ..no GPS lock ...it 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 ...so i used 23cm 1296.6 MHz instead.


    rx results on QO-100 can be seen here ... (last 12hours)


    https://pskreporter.info/pskma…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

    Hallo...


    JUST A NOTE ABOUT !!!


    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...???


    http://www.dg0opk.darc.de/Octagon_LNB_mod_March2017.html


    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

    Hallo...


    i got an similar model today...


    https://www.ebay.de/itm/AX-Bla…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...


    EDIT:

    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

    Hallo...


    difficult to get the old (working models).... they are out of market
    i you have luck you get one ?


    made some tests on newer models.... mostly NEGATIVE... some wobbling!

    OLD MODELS WORKING GOOD AND TESTET ALSO WITH TCXO INSIDE:


    OCTAGON OSLO CHARGE1208/1301 RDA3650M TCXO 26MHz (TXC-7N) LO:9388,9

    OCTAGON OTSLO CHARGE 1208/1301/1306 RDA3565ES TCXO 27MHZ (D75F) LO:9750 (THE BEST ONE)


    all newer MODELS looking not so good...


    maybe some progess in future...???


    73 de Michael dg0opk

    Hallo....


    this is the simple patch i used for my tests until now... (K3TZ design)...

    build in a 60cm PF Dish and working nice...


    can read my ssb signal with 0.5W (easy) and worked on FT8 in QSO down to 0.1W tested decodes 0.05 and 0.025W (QRA64) .... so i think not much is wrong here in this design...


    EASY and very CHEAP to build!


    73 de michael dg0opk

    Hallo...


    i got an SWL report from ON7KGK on my QRP tests yesterday evening after my QSO with DK2RO... (see attached)


    MY TX:

    LIMESDR + GNURADIO GRAPH (by DG0OPK) + AUDIO via PULSEAUDIO LOOP from WSJTX 2.0.0 ...to GNURADIO


    Amplifier(?):

    MMIC DRIVER max.10dBm + DL2AM DRIVER 0.5W max.. LIMESDR TX POWER was set to 40dB (max is 60dB)...


    TX-ANTENNA: PF DISH 60cm , simple patch feed


    NO GPS LOCK !


    BTW: i decoded the same on my monitoring RX...

    Hallo...


    today i made a comparision of WB-SIGNAL with the BATC Wideband Monitor with TT-S2 1600 and 85cm DISH + OCTAGON LNB


    DATV BEACON signal was set down by 3dB since yesterday... so nearly 7dB on BATC Monitor. (before it was >10dB at the WB Monitor with an 1.3m DISH).


    So i think... 85cm is big enough for receiving DATV ...

    It looks very good calculatet from AMSAT before... TNX


    73 de dg0opk