Email Detail

HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/RWNG7D6DQJJJFSKOEQLT46OS3SEB4BTN/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "000c01c7b158$6d4cda20$0301a8c0@Shop",
    "message_id_hash": "RWNG7D6DQJJJFSKOEQLT46OS3SEB4BTN",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/PFUGZ676R3TJDCZDCVW676TCFQKJQ2C2/",
    "sender": {
        "address": "juan-rivera (a) sbcglobal.net",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Juan Rivera",
    "subject": "[eagle] Re: 70 cm Receiver IF Spurs - Problem Solved",
    "date": "2007-06-18T03:26:13Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/NTVWS5O3UGOSFMWXCYKYSRLLDLTSI3T3/",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/7WXYXW6LEGLRLF2VYPJAOOY3IZT7XXWC/"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hello Lyle, Jim, and folks,\n\nThe uglier this gets the more interesting I find it!  I hope no one is\ngetting disheartened.  After all, this is why we all got involved in the\nfirst place, isn't it?  If it was easy it would be boring.\n\nI just cooked up an idea for a noisy power source that could be used during\npayload development and test.  I stuck my write up and a block diagram at\nthe end of my current log.  \n\nHere's the link:\nhttp://www.juanr.com/pages/hobbies/ham_radio/Eagle/Spur_Suppression.htm\n\nWhat do you think?\n\nShielding the CAN-Do inductor obviously won't solve all these problems but\nit might buy back 2 inches of space and that's worth the effort.\n\nLyle,\n\nMy suspicion is that the two VCOs on this receiver are also the most\nsusceptible to radiated EMI from CAN-Do.  I can't say for sure but it looks\nthat way to me.  Both are in metal cans soldered to ground.  The closest one\nwas about 2 inches away from the CAN-Do inductor.  I've more than doubled\nthat distance to 4-1/4 inches to get away from it.  That's a lot of EMI!\n\n73,\n\nJuan\nWA6HTP\n\n\n-----Original Message-----\nFrom: Lyle Johnson [mailto:[email protected]] \nSent: Sunday, June 17, 2007 7:44 PM\nTo: [email protected]\nCc: Chuck Green; David Smith; Dave Black (Work); Dave Black (Home);\[email protected]; Samsonoff@Mac. Com; Juan.Rivera (Work)\nSubject: Re: [eagle] Re: 70 cm Receiver IF Spurs - Problem Solved\n\nHello Juan!\n\nI have been watching all of this pretty much in the background for a \nvariety of reasons. IN addition to the CAN-Do! noise that you've noted, \nwe are also faced with a few power system unknowns that are likely to \ndwarf the CAN-Do! conducted noise:\n\n1) The spacecraft power will probably be coming from a distributed set \nof sources  that will be switching themselves on and off bus, with \nhysteresis in their switching logic.\n\n2) The various power sources may not be synchronized in terms of their \nswitching frequencies.\n\n3) As a result, well have both switching regulator noise from the \nregulators themselves, as well as varying source impedance as the \nvarious power sources attach and remove themselves from the power bus \n(due to spacecraft spin, varying power demand from transmitters, ...).\n\n4) The power system is not designed, so it is very hard to characterize it.\n\n From all of this, I think that all modules need to have excellent \non-board regulation and assume dirty power in terms of both switching \nnoise and source impedance.  I don't have numbers for this, but perhaps \na source impedance of 0.05 to 1 ohm is not unrealistic.  Similarly, \nswitching noise amplitudes on the order of 1 volt are likely.\n\nIf we can shield the CAN-Do! inductor to reduce its radiation, we \nshould. This will be a retrofit, of course.  The dynamic magnetic \nenvironment is not known at this time, and I think we've been assuming \nthat most radiated energy would be from the antennas, along with \n\"leakage\" from the power supply switching system.\n\n***\n\nIn a previous life, I had to deal with systems that included radios with \nVCOs that were susceptible to external fields. In the end, we had to the \nVCOs had to be shielded to make them essentially immune to such fields.\n\nSince we don;t yet know what the power system will be like in terms of \nconducted or radiated energy, we have to assume a pretty dismal picture \nfor both of these components and try to design our modules to be \ninsensitive to them to the extent practical.\n\nLou, any ideas on the power system and how it might look/behave/targets \nfor noise, load regulation, etc?  Any measurements available on the \ncap/cell charge/discharge distributed power system modules?\n\n73,\n\nLyle KK7P\n\n\n\n\n",
    "attachments": []
}