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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/ILICWS2KA7P6FBKJSATUONL2TJLSJZRV/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "CAJCSnOZtYepuU0NMBLv--PuQ096emH5Fet4fbc__bR6aYp=iAQ@mail.gmail.com",
    "message_id_hash": "ILICWS2KA7P6FBKJSATUONL2TJLSJZRV",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/2Z7A5WEGVPR2PSWGKAPKRAKLPEGGCPFF/",
    "sender": {
        "address": "scott23192 (a) gmail.com",
        "mailman_id": "120e10e05ba14969a11da0a96d21e355",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/120e10e05ba14969a11da0a96d21e355/emails/"
    },
    "sender_name": "Scott",
    "subject": "Re: [amsat-bb] ISS Packet Frequency?",
    "date": "2017-04-25T01:00:12Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/DJPCI7P3MNKJRTUYUYD4QN2S4VUD46PD/",
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Thanks for the feedback, Graham!\n\nI wasn't concerned with demod or decoding packets on this particular night;\nbut rather to run a wide-band capture with no doppler correction to allow\nthe transmitted signal to paint the doppler curve on my display to identify\nthe center crossing at closest approach.  That does a number of things for\nme like identify the transmitted frequency (at least as received by my\nhardware), verify my TLE's, and to get a visualization of how much doppler\nshift is occurring between AOS & LOS.\n\nIt does interest me quite a bit to try to characterize differences between\nthose who are seeing better performance -vs- those who are not, so you're\nright on to mention hardware.  We can't generalize, but I see \"some\"\nevidence since the freq change that the group having better luck might be\nthose with equipment like the FT-817 and the folks using the excellent\nKenwood HT's.  But it goes without saying that with such a large sample\ngroup, a VERY large number of people could step forward with minimal\nequipment reporting good success as well.  From my own testing I can\nobserve that I decode way more packets with an SDRPLay than with a cheap\nmobile rig or generic RTL-SDR.  I know that sounds obvious (that superior\nhardware gives superior results) but that's not my point... rather that it\njust \"feels\" like that wasn't so much the case with the previous 2-meter\nsetup.\n\nI could easily be wrong but when it seems like some experimentation might\nprovide some useful info to improve everyone's enjoyment of the resource, I\nhave a hard time leaving it alone!\n\n\n============================\n\nOn Mon, Apr 24, 2017 at 8:33 PM, Graham <[email protected]> wrote:\n\n> Scott,\n>\n> I had a look at the two noted images. The first thing that I noticed was\n> that the mode was set in both cases to wide band FM not narrow band FM. If\n> you are trying to copy ISS packet using WBFM that might be the source of\n> your problem. It could be that the new radio on the ISS has a somewhat\n> lower deviation than the old radio.  The second image (Spectravue) does\n> indicate that your receive might be a bit high in frequency.\n>\n> If you are not using your SDR to try and copy the ISS then perhaps you\n> should state what equipment you are in fact using; I may have missed it\n> from an earlier post.\n> I have been having good luck copying the ISS using my FT-817. Sometimes I\n> use a dual band VHF/UHF collinear vertical and sometimes a small yagi, the\n> yagi works better but the vertical still works OK too. I don't adjust for\n> doppler, I just set the FT-817 to 145.825. Doppler on 145.825 for a typical\n> pass is about +/- 3.5 kHz at least according to GPredict.\n>\n> cheers, Graham ve3gtc\n>\n> ===========================================\n>\n>\n> On 2017-04-24 22:20, Scott wrote:\n>\n>> Hi everybody.\n>>\n>> This is essentially a request for what I believe the scientific folks call\n>> \"peer review\"...\n>>\n>> I continue to try to understand why none of my equipment has been\n>> receiving\n>> the ISS digipeater very well since the switch back to 2 meters, despite\n>> the\n>> fact that the same hardware does well on terrestrial packet and in the\n>> case\n>> of 145.825 in particular, I have even received packets from PSAT since\n>> re-configuring for VHF reception on my Raspberry Pi / RTL-SDR iGate.  So,\n>> my point is that it isn't that NOTHING is working on 2-meter packet or\n>> 145.825 here.  And as I've mentioned in the past, I hear from others with\n>> similar stories so we're not sharing hardware or location.\n>>\n>> This evening there was a favorable pass here and I see on ariss.net that\n>> several stations were digipeated while the ISS was over the U.S.  Great\n>> news!\n>>\n>> I monitored that pass in receive-only mode with the same type of TXCO\n>> version-3 RTL-SDR that I use for my iGate.  The results were very strange\n>> and I hope incorrect.  I certainly would appreciate it if someone might\n>> repeat my test when time permits.\n>>\n>> Here is an image showing my SDR tuned to the local NOAA Weather Radio on\n>> 162.475.  By all appearances, my frequency display is accurate in the VHF\n>> band.\n>>\n>> https://www.dropbox.com/s/w1dll06xwinteap/NOAA-Wx-Radio-on-freq.png?raw=1\n>>\n>>\n>> ... without changing any settings other than frequency, the following\n>> image\n>> shows a Spectra-Vue plot of my reception of the packet transmissions from\n>> the ISS on this evening's pass:\n>>\n>> https://www.dropbox.com/s/s46o3pi87yk9t2h/spec-view.png?raw=1\n>>\n>>\n>> ... I took a ballpark stab at the center point of closest approach and\n>> unless I did something awfully wrong, it's roughly 5 KHz above the\n>> expected\n>> 145.825 frequency.  If by any chance this is accurate, it explains why\n>> I've\n>> been seeing poor reception here.\n>>\n>> (On the other hand, if my observations are completely wrong and flawed,\n>> this makes just over 1000 times that I've looked foolish!)\n>>\n>> Anyway, if anyone is setup to make similar observations, I would imagine\n>> that we would all like to know if there is a frequency issue up there.  If\n>> not, then of course I'm sorry to tie up the mailing list!\n>>\n>> 73!\n>>\n>> -Scott,  K4KDR\n>> Montpelier, VA  USA\n>\n>\n",
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