sl3s + 21v pi + frequency sweep from 150mhz to 2150mhz

Discussion in 'DIRECTV General Discussion' started by tdbone1, Jan 21, 2019.

  1. Jan 23, 2019 #21 of 260
    slice1900

    slice1900 Well-Known Member

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    The 9 SWM channels with center frequencies starting at 974 MHz and going up by 102.06 MHz per channel are clearly visible there.

    The LNB isn't outputting anything (deliberately) below that SWM range, other than a narrow (38.4 KHz) FSK signal at 2.3 MHz. I guess that "haystack" is simply unfiltered noise.
     
  2. Jan 23, 2019 #22 of 260
    HoTat2

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    Any idea then why the SWiM LNB doesn't enter into alignment mode with no IRD detected?

    And what exactly the "alignment mode" constitutes?

    That the integrated SWiM multiswitch's agc circuit is disabled to allow the SWiM carriers to actually vary with incomming satellite signal strength as the dish is adjusted?

    And what the ASL-1 really does to this SWiM output we see on the spectrum analyzer that allows 101W signal strength to be measured between 1445-1850 MHz on one port. And 119W signal strength between 950-1310 MHz on the another port for installation meters in the pre-AIM days?

    Sent from my LM-V405 using Tapatalk
     
  3. Jan 23, 2019 #23 of 260
    P Smith

    P Smith Mr. FixAnything

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    So, you found freq map (it was printed on a box of WB68 switch ;) ).
    That's what analog LNBFs output to L-Band. You are dealing with SWiM.
    ASL-1 discussion never been based of its technical data/info, just speculations. So, you're on uncharted territory on your own.
     
  4. Jan 23, 2019 #24 of 260
    HoTat2

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    Although I've always been slightly uncomfortable with calling it solely the "L-band", since that is really only 950-2150 MHz. So technically doesn't include the LNB down-converted Ka-lo band of 250-750 MHz.

    Perhaps it's really the "UHF/L-band" to be more precise?



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  5. Jan 23, 2019 #25 of 260
    P Smith

    P Smith Mr. FixAnything

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    if you like, be it that way
    DTV messed not a first time … and we will see more from them :D
     
  6. Jan 23, 2019 #26 of 260
    slice1900

    slice1900 Well-Known Member

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    My understanding is that the ASL-1 is basically a diplexer - it has a filter on each output so a cheap meter can look at 101 & 119 separately.

    The question is, what exactly is the SWM outputting before it hits the ASL-1? Based on what we see here, it is outputting 9 SWM channels. The ASL-1's filtering would drop the "middle" channel so you'd get four from 119 and four from 101, with an SL5S. As this is an SL3S, all nine channels must be from 101.

    Theoretically, our "data gatherers" over at cutting edge might be able to determine which transponder numbers correspond to which channels in alignment mode. Not that this matters for performing the actual alignment.
     
  7. Jan 23, 2019 #27 of 260
    P Smith

    P Smith Mr. FixAnything

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    I would say you'll need to point to others - SWIM's data gatherers :D
     
  8. Jan 23, 2019 #28 of 260
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Since this is a SDR, "god knows" what it is.

    Somewhere between 10x and 100x "more dollars" gets one a "Spectrum Analyzer" with enough hardware to be of use.

    [my 2¢]
     
  9. Jan 23, 2019 #29 of 260
    P Smith

    P Smith Mr. FixAnything

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    if PSA-37D is OK, I'm in ;)
     
  10. Jan 25, 2019 #30 of 260
    tdbone1

    tdbone1 Member

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    Oh i think my sdr is of great use.
    Get an SA 10x or 100x more $ and compare that data to the data i provided
     
  11. Jan 25, 2019 #31 of 260
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    What I haven't seen is noise levels/x
    If I don't know what the bottom is, how can I know what the top is?

    What I've seen so far isn't anything more than a toy for a hobbyist.

    It's much better than an attempt out of Washington [state] a few years ago.
     
  12. Jan 26, 2019 #32 of 260
    tdbone1

    tdbone1 Member

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    Show me a photo or video that provides more info on SWiM in alignment mode then what i provided
     
  13. Jan 26, 2019 #33 of 260
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Not my job


    When I used a spectrum analyzer, I analyzed.
     
  14. Jan 26, 2019 #34 of 260
    P Smith

    P Smith Mr. FixAnything

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    seems to me it's red herring
     
  15. Jan 26, 2019 #35 of 260
    tdbone1

    tdbone1 Member

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    is there a way to get the lnb to switch modes (polarity and Ka/Ku bands) manually without using a SWiM receiver?
    i mean could i use my sound card output jack to send a 38khz/22khz signal to switch modes?
    also if i switch from the official swim 21v power inserter to like a 13v power inserter do you think the lnb would switch modes also?
    modes = polarity or Ka/Ku bands

    i should add that im not wanting to use this to watch tv.
    i want to use the dish for astronomy and would like to be able to switch polarity and Ka/Ku depending what i want to research.
    meterors the sun and well just anything i can find interesting.
    i dont have enough money to buy a real down converter so i had read articles on the sup2400 that P Smith had mentioned and i though i think i might have something like that.
    with what i have: SDR, SL3S attached to original Directv dish, 21v PI and a descent laptop.
    with it being stuck in "Alignment Mode" what can i do with it?
    im trying to figure out a way to change modes with what i have but would be willing to buy a ird device if it would help improve the projects above.
    i was thinking the ird device would be in the way but it appears its needed to switch modes.
     
    Last edited: Jan 26, 2019
  16. Jan 26, 2019 #36 of 260
    slice1900

    slice1900 Well-Known Member

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    The best way to source different polarities would be a multiswitch, which you can buy on eBay dirt cheap. Just plug the dish into whichever polarity you want to generate.

    Obviously that only works with a legacy LNB, not a SWM LNB.
     
  17. Jan 27, 2019 #37 of 260
    P Smith

    P Smith Mr. FixAnything

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    nope
    it controlling by cmds sending by FSK at 2.3 MHz
     
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  18. Jan 28, 2019 #38 of 260
    tdbone1

    tdbone1 Member

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    So is there anything i can do with it as far as radio astronomy with it in alignment mode with AGC off (to my understanding) and the Ku band?
     
  19. Jan 28, 2019 #39 of 260
    P Smith

    P Smith Mr. FixAnything

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    just get legacy (non-SWiM) LNBF combo (99/101/103) with WB68 switch and control it by 13/18V and 22KHz tone
    ebay and craigslist are your source
     
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  20. Jan 28, 2019 #40 of 260
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Who's going to mention circular polarization?
     

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