USALS motor encoding and max arc size

Discussion in 'Free To Air (FTA) Discussion' started by Jomo, Dec 18, 2017.

  1. Jomo

    Jomo Topic Starter Member

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    Hi there,

    Really quick question. I installed an HH120 (Stab) motor over the weekend. So far so good. But I am using a Manhattan receiver, which is a bit underpowered, and it is *slow* driving the motor. I am considering switching it out for my other receiver, the GeosatPro, to see if it is any better.

    Here's the question...does the HH120 "know" where it is, so that I can just swap out the receiver and not worry about the position of the mount? Or do I somehow have to "zero" the motor before I switch out the receiver?

    Also, does anyone know off-hand what the max arc of this motor is? I am in Los Angeles, which means I have most of my satellites to the east side of south, and I'm curious how far I can really push it east (or west) for that matter. G18 at 123W is actually my alignment sat on Ku!

    Thanks!
    Joe
     
  2. KE4EST

    KE4EST SatelliteGuys Is My Second Home
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    You should be able to switch STB's as you wish, if using USALS. Just make sure both boxes have the same Lat and Long programmed in.
    You only have Ku to 127W so you are good to the west from your location. :D
     
  3. Jomo

    Jomo Topic Starter Member

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    Thanks! Yep, using USALS so I will be careful about the lat/long.

    I think I can actually see all the way to IS-18 at 180E as I have a clear view of the horizon (not sure if there is any footprint though). But unfortunately I think that's probably outside or right at the arc of the motor. Looks like there is a lot of stuff on Ku on that bird.
     
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  4. a33

    a33 SatelliteGuys Pro

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    The USALS calculation in a receiver usually has not a very wide range, 50 or 60 degrees both ways if I remember right?
    But outside the USALS range, you can move to satellites further away from south via 'normal' diseqc 1.2 commands.

    greetz,
    A33
     
  5. Magic Static

    Magic Static FTA Geek
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    The HH120 has a movement angle of + or - 62°
     
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  6. phlatwound

    phlatwound FTA Bumpkin
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    IIRC the gearing on the HH120 is rather "low" and takes longer than other motors to go it's full travel, that is part of the reason that it is able to handle the larger dishes.

    Don't know if you will see any speed difference with the GeosatPro but good luck and let us know.
     
    #6 phlatwound, Dec 18, 2017
    Last edited: Dec 18, 2017
  7. Titanium

    Titanium AI6US
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    The receiver brand or model will have little effect on the motor movement speed.

    The motor will move faster if the "GoTo" satellite is on a horizontal transponder. The horizontal transponder selection provides 18Vdc to the motor rather than a vertical transponder's 13Vdc.
     
  8. Jomo

    Jomo Topic Starter Member

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    I finally was able to play with the GeosatPro today (vs. the Manhattan). It seems to be a better unit - I get both a better signal quality from this receiver, and yes, the positioning is faster. But I think that may have to do more with the software. On the Manhattan, the "dish moving" info box seems to stay onscreen and hang a lot longer than it actually takes to move the dish. On the Geosat, it positions quickly and it's done.

    As for the HH120, yes, I can get all the way to 180E with the motor. However, it's way out on the end of the arc for me - maybe just a few degrees within the limit - and when I positioned the dish back, the main satellites in the middle of my arc were off just a fraction of a degree (i.e. I could nudge the dish with my finger and get it back to full signal), but given that just going out that far on the arc could have such a bad effect on the rest of my sats, I probably won't do that again!
     
  9. Jomo

    Jomo Topic Starter Member

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    Actually, a follow up... I went up to the roof to watch the dish move. It's not just the software. The Geosat is far better at driving the motor. It's actually a ton faster.
     
  10. Titanium

    Titanium AI6US
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    Are you certain that while comparing speeds, both receivers were tuned to the same polarity? The observation that one receiver outputting 18Vdc at 450mA is moving the motor faster than another receiver outputting 18Vdc at 450mA seems unlikely....


    One would observe movement speed differences if one receiver was tuned to a vertical transponder (slower) and the other on a horizontal transponder (faster). Both receivers in this test are similarly rated on the LNB power.
     
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  11. Cham

    Cham VE4GLS
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    Too bad receivers don't automatically use 18v to move the motor, then switch to LNB voltage once at position or close (within 1 degree) for signal aqusition.
     
  12. Titanium

    Titanium AI6US
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    18Vdc during motor movement is an option in many receivers. The Enigma 2, other Linux based OS and some computer software programs have a menu setting for user selection.

    If properly implemented, the receiver only provides 18Vdc in continuous move mode and not step mode. The receivers that implement 18v for all movement makes fine tuning positioning on a vertical transponder next to impossible! :)
     
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  13. N5XZS

    N5XZS SatelliteGuys Pro

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  14. Titanium

    Titanium AI6US
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    Have viewed c-band from this bird before, but never KU. Of course, a pine tree is blocking my 90cm from 150w further West, so until I set a different dish, there will be no checking from my location. ☹️
     
  15. primestar31

    primestar31 SatelliteGuys Master

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    You want to borrow a chainsaw? LOL
     
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  16. Martyn

    Martyn SatelliteGuys Pro

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    Let me know what you get. I know I can get it here but haven't tried. I think I'll need a new ku-band LNB as mine are all US models, from 11.7 up I guess. I need to check the labels.
     
  17. Jomo

    Jomo Topic Starter Member

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    Yep, just to confirm, I got the dish to that spot, but did not get anything...to be expected since I'm using 11.7 - 12.2GHz gear.

    Really happy with the HH120 and USALS overall, though. Seemed to be a marked improvement when I was just a teen 20 years ago mucking around with our family's old C-band dish and actuator.
     

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