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/TTPINAFCIUBGKYWPT6ALCQ3YOZQT4D3E/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "TTPINAFCIUBGKYWPT6ALCQ3YOZQT4D3E",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/TTPINAFCIUBGKYWPT6ALCQ3YOZQT4D3E/",
    "sender": {
        "address": "ki5dq (a) yahoo.com",
        "mailman_id": "5f5322ae29214493aae6ce4aedc4de51",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/5f5322ae29214493aae6ce4aedc4de51/emails/"
    },
    "sender_name": "J. Hunt",
    "subject": "[AMSAT-BB] Re: UHF preamps",
    "date": "2022-12-27T10:26:46Z",
    "parent": null,
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": " \nHi Tom,\nBeko Elektronik, represented by Island Amplifiers has your answer(s) with a complete remote 440mhz preamp with internal T/R by-pass relay.  \n    https://islandamplifier.com/  \n\n   https://www.beko-elektronik.de\n\nAnother source is Down East Microwave \n         https://www.downeastmicrowave.com/\nBest of knowledge, neither had a 1296 (23cm) complete remote pre-amp with internal T/R by-pass relay.With my engineering background, I made a 600 watt model.  Works great on the weak signal / tropo scatter.  \n\nThanks n 73,JamesKI5DQ\n   On Monday, December 26, 2022 at 11:04:54 PM CST, Zach Metzinger via AMSAT-BB <[email protected]> wrote:  \n \n On 12/26/22 22:31, tjschuessler--- via AMSAT-BB wrote:\n\n> I do have a question for Yaesu FT847 users.  With that radio, you can\n>  power a Preamp via the built in Bia- T power inserter, And assume\n> that when this mode is turned on, it cuts the inserted DC to the\n> preamp as the tranciever goes into transmit.  Does this work fast\n> enough to protect, even RF switched preamps?  That might be a good\n> safety measure as I have traditionally used external DC to power my\n> preamps.\n\nI have a homebrew UHF LNA that initially suffered the same fate as yours\nbefore it was modified with protective PIN diodes on the output.\n\nI am powering the relays which switch from \"inline\" (during RX) to\n\"bypass\" (during TX) with the FT-847's bias-tee function. I found that\nthe relays might not be quite fast enough to avoid getting a significant\nRF pulse back into the LNA output. This was most pronounced with CW,\nwhile SSB was tolerated better -- probably because I waited a moment to\nspeak after pressing the PTT.\n\nIn a previous posting, I wrote:\n\n> http://www.n0zgo.net/lna/70cm/max2640/70cm_lna_max2640_annotated.jpg\n> \n> (The BAR64 PIN diodes were added to protect the MAR3-SM+ output gain\n> block when transmitting. Without those, the MAR3 was dead within a\n> few minutes of use at >10W TX.)\n\nYou might try putting some of those PIN diodes into your unit. It might \njust keep it from going up in smoke.\n\n--- Zach\nN0ZGO\n\n-----------------------------------------------------------\n\nSent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available\nto all interested persons worldwide without requiring membership. Opinions expressed\nare solely those of the author, and do not reflect the official views of AMSAT-NA. \nAcceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/\n\nView archives of this mailing list at\nhttps://mailman.amsat.org/hyperkitty/list/[email protected]\nTo unsubscribe send an email to amsat-bb-leave(a)amsat.org\nManage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org\n  \n\n\n",
    "attachments": [
        {
            "email": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/TTPINAFCIUBGKYWPT6ALCQ3YOZQT4D3E/",
            "counter": 2,
            "name": "attachment.html",
            "content_type": "text/html",
            "encoding": "utf-8",
            "size": 5709,
            "download": "https://mailman.amsat.org/hyperkitty/list/[email protected]/message/TTPINAFCIUBGKYWPT6ALCQ3YOZQT4D3E/attachment/2/attachment.html"
        }
    ]
}