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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/B42J7V53UNKCX2CRM3JMDV7VT5S32HAN/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "B42J7V53UNKCX2CRM3JMDV7VT5S32HAN",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/ODX4VHJ3ET6VHGXQZ5P3DW6JMDL27PKF/",
    "sender": {
        "address": "greencl (a) mindspring.com",
        "mailman_id": "5421c5ff9a12494f8f7bd304db4ac696",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/5421c5ff9a12494f8f7bd304db4ac696/emails/"
    },
    "sender_name": "Chuck Green",
    "subject": "[eagle] Re: Preliminary CAN-Do EMI Findings and Suggestions to Mitigate in the 70 cm Receiver",
    "date": "2007-06-15T14:53:06Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/ODX4VHJ3ET6VHGXQZ5P3DW6JMDL27PKF/",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/HFVYGT4BHR4NPUYO4U5CNP3KJHA5T6A4/"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Juan,\n\nI have a couple of suggestions.\n\nBased on previous messages I presume you will not want to use the \nswitched power from the CAN-Do! regardless of the noise issue. I also \nsee that the switch transistor in the CAN-Do! is in the same area of the \nPCB as the CAN-Do! power supply.\n\n1) Put a jumper between pins 2 and 3 of the switch transistor (TO-220). \nThis will bypass the switch and any noise it is picking up from the \npower supply. This will keep the 2 amp fuse in your power source and the \ncurrent measurement circuit.\n\n2) You might also eliminate the 2 amp fuse from your power source by \nplacing a jumper from pins 1,9 of the DA15P to pin 2 of the switch \ntransistor after removing the transistor (or just cutting it's leads). \nThis will preserve the current measurement of the power going to your \nmodule.\n\n3) You might also bypass everything by putting a jumper from pins 1,9 of \nthe DA15P to any unused user pins on that same connector (pins \n2,3,5,10,11,12) then picking up the power from the corresponding user \npins on the 40 pin connector. If you do this, you should provide a \ncurrent measurement circuit on your module and attach it's output to one \nof the analog input pins of the 40 pin connector.\n\nThe above may eliminate or reduce the noise in your power source while \naccomplishing other power source objectives.\n\nChuck\n\nJuan Rivera wrote:\n>\n> All,\n>\n> I’ve completed a preliminary evaluation of the CAN-Do RFI problem. \n> Please see my log for details by clicking here \n> <http://www.juanr.com/pages/hobbies/ham_radio/Eagle/CAN-Do_Noise_Troubleshooting.htm>.\n>\n> Preliminary Findings...\n>\n> 1. The spurs seen in the receiver IF enter the receiver in two ways\n>\n> o As radiation from the CAN-Do inductor\n>\n> o Via CAN-Do module switched +14 VDC power on pins 39 and 40\n>\n> 2. I/O line filtering appears to be unnecessary\n>\n> 3. The switched power from the CAN-Do module pins 39 and 40 must be \n> filtered\n>\n> 4. The CAN-Do module will either have to be kept physically separated \n> from any sensitive components, redesigned, shielded or a combination \n> of the three.\n>\n> 5. Moving the Can-Do module 2-1/4\" forward of its normal location on \n> the receiver PCB lowers the EMI level below the noise floor.\n>\n> Suggestions...\n>\n> · Create a full size PCB for the next generation receiver and shift \n> the RF components to the back of the board (away from the CAN-Do module.)\n>\n> · Add DC input filtering to the receiver\n>\n> 73,\n>\n> Juan\n>\n> WA6HTP\n>\n> ------------------------------------------------------------------------\n>\n> _______________________________________________\n> Via the Eagle mailing list courtesy of AMSAT-NA\n> [email protected]\n> http://amsat.org/mailman/listinfo/eagle\n>   \n",
    "attachments": []
}