Dish / Antenna Alignment

  • After very enjoyable meetings and discussions at HAMRADIO, Friedrichshafen, I am now ready to setup my ground station. I have 1.1m Triax dish for receive, which i believe should give me good receive performance.


    I have checked on BATC web site for antenna elevation and bearings - I have also an app on my phone which gives me bearing and elevation information too. My question is, how accurate does your dish alignment need to be...? from calculations, my bearing is 148.3 degrees and an elevation of 26.6 degrees - how much tolerance will i have here ? is it just a case of finding the sat and fine tuning for peak signal...?


    Many thanks...


    de G0TKZ

  • another useful link to align your dish.

    On the left your QTH and on the right the satellite position, 26 ° E

    The rotation of the LNB called LNB Skew is important

    https://www.dishpointer.com/

    In dishpointer.com ES'HAIL-2 is included with 25.9 E as "ES". I think they have internal difficulties to display the sign " ' " in their web app and the rest of text is cutted off.

  • another useful link to align your dish.

    On the left your QTH and on the right the satellite position, 26 ° E

    The rotation of the LNB called LNB Skew is important

    https://www.dishpointer.com/

    I use this site me also, I think is 25.9E ES. First set skew, second set elevation using info in the back side of dish. Then using a level meter try to find any nearby satellite and adjust elevation. Then using an rtl-sdr for example try to see the beacons turning left and right the disk without adjusting elevation. After you see the beacons fine adjust the elevation.

  • I've got a triax 1.1m too. I just did a test and I can see the NB transponder beacon at +/- 5 degrees.


    However it becomes more difficult if you dont know exactly what frequency to look at because of LNB drift. I started with a 60cm ex sky dish to find the frequency first and then moved it to the triax dish.

  • You can receive the beacon with only an lnb, this way you can find the direction of the sat, and fine tune the dish afterwards. I don't use compass for searching mostly, just elevate the dish at 26° and turn around between E and S. Easy to find it.


    73's Jerry

  • Many thanks everyone for your help and tips here..!


    Unfortunately, I've not had a lot of luck so far.....my setup is DX-Patrol LNB and controller, Leo-Bodnar GPSDO reference, 1.1m Triax Dish and Airspy R1 SDR for the receiver, with SMA cables and F-Type patch leads


    I have the directional info from the links you have given me, heading 148.5 degrees and elevation of 26.5 degrees, and -19 skew.


    I'm pretty happy i have the heading correct, I have 148 degrees on the arm of the LNB feed, and i have that from multiple sources, I can only go on whats on the back of the dish for elevation - and the mount on there is not the easiest to move...


    Looking at SDR# - I have the screen at 1MHz width, I'm centered on 739.550MHz for the low band beacon, looking for the rise in background noise of the transponder... No matter where I point the dish, up down - left and right, absolutely nothing...no change to spectrum display, same flat noise level.


    I have a SatFinder app on my phone, and i can see the satellite with an unrestricted view.


    I'm trying to figure out where to look first...? short of starting to replace items (cables should be straight-forward) I'm not sure.

    I am thinking about getting a TV Sat installer to align the dish and see if he can see the ES'hail-2 DVB-S beacon on a signal meter, that would at least prove alignment of the dish, before i start looking at the individual components.

    I've also considered buying a sat signal meter, but slightly cautious as they have an indicated frequency range from 900MHz, and ideally in need to reach to 739MHz..

    Any tips or pointers (!) would be appreciated...!

    73's / G0TKZ

  • G0TKZ have you increased the AIrspy R1 gain setting for max sensitivity in the respective SDR software ? When pointing the antenna to the sky, you show see the difference if you cover the LNB with your hand (which is warm.. the sky is cold).


    Only if you see this (small) difference, you will be able to see the satellite.

  • Hi Achim - many thanks for your tip here..!

    I have now set the SDR# max gain for the LNB. I also aligned to the bearing in need for QO-100. I checked the noise floor level and shading of the waterfall - I covered the LNB face with my hand - and released. I could see no discernible change in the noise level or the color grading of the waterfall...


    Can you clarify how i could improve this situation..? would in need to consider another LNB..or perhaps raising the dish higher above ground (even though I have a good view at ground level) ?


    Does this mean I'm not able to receive the satellite transponder..?


    Appreciate your input here..!

  • Do you see plenty of noise from the LNB? Their output is usually huge. When a friend of mine thought he had tried everything, he eventually found that his LNB LO wasn't at the frequency he thought it was on, so it might be worth tuning up and down a bit.

  • Hi Guys,


    Thanks again..!

    Yes, i do have a confirmed 12v supply to the DX-Patrol controller (injector) - and when i disconnect the RF input to the Airspy, the noise level does drop by around 25db (at 739MHz) - interesting though, when i tune up the band to around 850-900MHz the LNB noise levels increase massively, I'm assuming that's the TV IF's coming through..?

  • Hello,


    do you have a DVB-S receiver? If "YES" you could set it to one of the Astra 2 (28,2°) frequencies (ASTRA 2 should have a big signal in your area and you should see an image even when you are "about" the right direction.

    Having found ASTRA 2 you can use your amateur equipment and turn the dish slightly "clockwise" (towards west) and you should see signals of QO-100.

    With a Satfinder you will find a big signal on 28,2. The signal of ES Hail is "overlapped" by the ASTRA 2 signal thus you will not find ES Hail with the Sat-finder directly. You have to perform the above procedure (finding ASTRA2 and slightly turning towads west).


    Perhaps there was something in my text which helped you just a little bit.


    73 de Johannes

  • @G0KTZ When you remove the connector from the Airspy, is there something else connected to the IF-port of your LNB?


    If the answer is 'yes' (because you said the noise level dropped around 25 dB) try to load the 'disconnected connector' with 50 Ohm. The open line can be an open 1/4 lambda stub (or uneven multiples of that) for 739 MHz.


    I had this during a /P operation and somebody wanted to connect his Minitiouner on the IF-out port of my transverter. I connected the cable, the noise level decreased drastically, but when the cable was connected to his Minitiouner everything was ok.