WB BEACOn MER

  • 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

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

    Hello Michaell,

    great work! Thanks.

    Whats about the weather conditions?

    I observe different reception values depending on the weather, clouds, humidity etc.
    It would be interesting if in all measurements a parallel operated "reference antenna" would be measured to take these weather effects into account ....

    73s de Robert

  • 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


  • Hi all, copied over from anther parallel thread


    I have been doing some tests with 3D printed lens antennas provided by Malcolm, G0UHY. I was concentrating on the MER of the DATV beacon as a metric, but also recorded the strength of the CW beacon (noise floor is -115 dBm in 3.5kHz bandwidth). Here are the results:





    Culprit DATV Beacon MER CW Beacon
    Standard rocket Lens 10.7 -79
    Short cone 9.5 -80
    Long cone 10.1 -79
    Cylinder 9.1 -81
    No lens 9.6 -80


    &thumbnail=1





    The dish is a 2.4m channel master offset. It has a F/D of 0.6. The poorer performing lenses may be better at lower F/D, but I only have one dish so can't test this.


    Mike

  • Hi Michael,

    at a portable use on 19.05. I have the DATV bake with a No Name 60cm Dish (55cm effective) and

    Octagon OTLSO Slim TwinLNB with GPSDO with MER 5.2 dB received.

    With LNB GM201 and GPSDO MER only 4.3dB.

    RX: MiniTiouner Express

    I had the dish on a tripod for the exact alignment

    Thank you for your measurements, 73 Jürgen

  • From:

    DL1GNM going to be QRV soon


    • Hirschmann dish 120cm F/D 0.68 (129cm x 120cm (H x W), same as GOONHILLY).
    • LNB HD-Line HD-BP2, not modified yet. A71A beacon, clear sky.


    Venton Rocket Lens LNB seen as in picture: MER 5.2dB D2 (not in focus !)

    POTY with POTY lens but without radom: MER 6.9dB D4

    POTY with Venton Rocket Lens, but without radom: MER 8.8-9.0dB D6

    POTY with Venton Rocket Lens, radom old position: MER 7.7dB D5

    POTY with Venton Rocket Lens, radom new position: MER 8.7-8.9 dB D5/6


    73 Mike

  • For every lens you need to adjust the focal point, because the phase centers are not the same.

    I agree - As I observed with my dish: Venton Rocket Lens LNB seen as in picture: MER 5.2dB D2 (not in focus !) Usually you get good results with this lens. But not at that position I've put in this VENTON LNB.

  • Hallo ...


    i got today an new personal MER record of the DATV BEACON on my 120cm Dish after rebuilding the RX-Antenna...


    10.4dB at 14:43 local time... (look in last line of screenshot)


    screenshot is made after this time and with 4 strong DATV signals so the beacon MER drops to ONLY 9.1dB but the EBS-software recording the maximum level


    info about my setup:

    RX DISH LAMINAS OCF-1200 OFFSET DISH

    LNB TWIN WB/NB with TCXO (27MHz! LO 9750/10600)

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


    EDIT:
    FOR COMPARISION ... in LOCATION CENTRAL DL JO50


    BADR4 26east SIGNAL 11996H SR 27500 is normally at 11.8dB

    BADR4 26east SIGNAL 12168V SR 27500 is normally at 11.8dB also (if polarity off LNB correct tuned)


    73 de dg0opk

  • Hallo all...

    after checking my receiving systems this weekend i could detect an loss of MER of the DATV Beacon on 10492.5 ...

    it is about 0.3-0.5dB weaker thank in the weeks and the other times before


    the effect is on all my 3 receiving systems nearly the same but maybe some detuning of strong winds ???

    level with empty tranponder (only beacon seen)


    85cm LNB at Center MER 7.2 (before 7.8dB - sometimes over 8dB)

    85cm LNB 7degrees offset MER 6.5 (before 7.2dB)

    120cm Offset MER 9.3 (before 9.6-9.8dB)


    Can anyone confirm?


    EDIT:

    the TV Signals from BADR 4 12168 V ,11996 H are unchanged and reaching 11.5 to 12 dB on my 120cm


    73 de Michael dg0opk

  • Hallo...

    got today some more level now... also with snowfall on the QTH....

    9.6dB is reached again on 120cm ...nothing was changed on the setup ....


    maybe the wheather is going good now in DOHA... ?? again


    @ DH2VA

    and maybe we have really some "ionospheric scintillation" depending on the local position of the receivers?

    i dont know... but maybe it is interesting to watch about this...


    73 de dg0opk

  • Very interesting. This remembers me to my SWL-time as teenager. In the wintertime with snow I had always better reception. Today I receive DVB-T2 TV from Donaueschingen, South Germany. The signal quality is also better now with snow around.


    Good reception and 73 :)

  • Hallo Robert and Thomas..

    tnx for your response ....


    but note ... we are not using an terrestrical radio path... we are using free space propagation with LOS (line of sight) so it is very interesting to monitor the changes of an LOS path which maybe only depends on some changes in the ionosphere at 10GHz ... ??

    never though and seen before that there are changes in path loss ...


    yes they are changes on heavy rain on bad weather conditions with thunderstorms (rainscatter) but changes on clear sky?

    (this is what i mean as a goal)


    Very interesting to hear someting about

    73 de dg0opk