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Questions about this weekend's ISS slow-scan TV event

Discussion in 'Satellite and Space Communications' started by AF7IN, Feb 8, 2019.

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  1. K3RLD

    K3RLD Ham Member QRZ Page

    The event got off to a rocky start, but ended very well. I missed our 1800z pass, but my satnogs station got an image. Good times!

    Remember to donate to ARISS if you enjoyed the event!
     
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  2. AF7IN

    AF7IN Ham Member QRZ Page

    Beautiful!!!!

    I'm going to have to live vicariously through you for that last pass. Got set up at the park & invited friends and family. Thought i had a laptop ready to roll for real-time display but something went wrong so we missed the first image though the audio was nice & strong. So I hastily switch to my recorder during the pause between images and what do I do? Plug into the headphone jack instead of the mic.

    But never fear. There's an AO-92 pass coming over in 8 minutes. At least I'll have something to show them!

    Low on the horizon I start hearing voices - all but my own. "Gee, wonder why I can't be heard????" Check this, check that, blah blah blah. Then I hear someone say during the course of a qsl "you're my first L-band contact". Yeah... that might have something to do with why I couldn't TX. LOL.

    [​IMG]
     
    Last edited: Feb 10, 2019
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  3. WD9EWK

    WD9EWK Ham Member QRZ Page

    Did you hear me on that AO-92 pass? I heard that exchange you mentioned.

    73!
     
  4. AF7IN

    AF7IN Ham Member QRZ Page

    Absolutely! Loud & Clear. It was your call-sign riding a 70cm wave right past the satellite and into the eternity of space :D
     
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  5. WD9EWK

    WD9EWK Ham Member QRZ Page

    You can see what I was using yesterday for my AO-92 L/V setup, from a post in another thread on this forum. Two radios, one for the uplink (Alinco DJ-G7T) connected to a 10-element Yagi, and the other (Kenwood TH-D74) connected to my Elk log periodic to hear (and record) the downlink.

    73!
     
  6. KD0KZE

    KD0KZE Ham Member QRZ Page

    Here are three of my better captures. Rig setup is a Kenwood TM-V71A + RC-D710, Comet GP-3 vertical, tip of the antenna is about 20' off the ground. I have a special audio cable from my rig running directly into the PC headphone+mic port, decoding real-time on Linux w/QSSTV. Never an optimal setup with a fixed vertical omni. But hey, we've had -50's wind chill recently (Polar Vortex) and keep getting dumped on with snow. And this lets me RX unattended too.

    I got 11 images total, though missed the first pass. A couple images were partial, the others had varying degrees of static.

    I wasn't in the shack when most of my images were captured, and unfortunately I didn't take note (nor can I find in the QSSTV docs) completely how the image filenames are generated. It looks pretty clear it is like this:

    {MODE}_YYYYMMDD_HHMMSS.png

    However, I don't know if the time is UTC or local (CST, -6 in my case).

    First was named PD120_20190209_234841.png
    Second is PD120_20190210_180058.png
    Third is PD120_20190210_180817.png

    PD120_20190209_234841.png

    PD120_20190210_180058.png

    PD120_20190210_180817.png

    73, KD0KZE / Paul
     
    Last edited: Feb 12, 2019
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  7. AF7IN

    AF7IN Ham Member QRZ Page

    That is cool as h*((, Patrick!

    I'm a big fan of making fun stuff with PVC ;)
     
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  8. N4UFO

    N4UFO Ham Member QRZ Page

    OFF TOPIC WARNING!

    Really... then how about this? Used it to work into three other continents on satellites. :cool:

    sat antenna.JPG
     

    Attached Files:

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  9. AF7IN

    AF7IN Ham Member QRZ Page

    Nice, Kevin. :cool:

    Where did you find that Y? I've never seen a fitting like that before. And what are the fittings where your coax enters the antenna assembly?

    9913?
     
  10. N4UFO

    N4UFO Ham Member QRZ Page

    First off... a disclaimer. I cannot recommend putting the 2m antenna behind the UHF like I did... had some problems with 2m third harmonic coming back down the UHF line. But the actual plans for the 2m were from the 'IOio' design and the uhf is a WA5VJB cheap yagi.

    I used that 'double wye' fitting (found at Home Depot) because I planned on adding a small piece of pipe to each side to house some preamps. However, while the PC boards did fit down inside the pipe, the preamp kits I bought were very cheap and not only didn't help, they actually made matters worse. (plus, water managed to get in there anyway) Coming off each side of the double wye is a short piece of pipe, to a fitting, and then, as best I remember, those are non-threaded PVC plugs with SO-239 chassis mount jacks shoved tightly into the fitting. And no, it was some cheap RG-213 I picked up in a trade... not the best to be using for VHF/UHF but the price was right.

    Here's another pic I found with a longer piece of pipe and the preamp inline... Oh, and that stuff around all the junctions is white duct tape, believe it or not.

    sat antenna old.JPG

    But rather than focusing on the double wye, the key centerpiece to all that PVC artwork was the 22.5 degree elbow I used to get the tilt. You know, I must have spent an hour and a half with a clip board and pen in the PVC aisle at my local HD figuring all that out... all design attempts started with that elbow. :)

    This was mostly just a 'trial run' on the cheap to see what I could do and to learn more about sat ops, antenna characteristics, etc. I think it was worth every bit of the $40 in PVC and copper wire, as I had fun, learned a lot and found out that I did want to step up to a full AZ-EL system... Playing with all this, I learned about coax losses, preamp quality, harmonic interference and much more.

    Bottom line... maybe not the best design to copy. o_O

    But the idea of experimenting and gaining more understanding about sat antennas before plunking down a lot of money... good plan. I ended up investing in good preamps, a used AZ-EL rotator and then went cheap on some of the other stuff. At the time, a lot of guys were still thinking you needed big long yagis with switchable circular polarity to work sats... to me, modest antennas were fine and even single polarity was do-able with patience. So instead of $500 on antennas, I got away with about $100 and a pair of used yagis. - Your mileage may vary, and always consult your satellite professional on what is right for you... ;):D

    73, Kevin
     
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