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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/T4VYQLLCRWMFASZIQ72EGRWGVFTCUJRY/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "T4VYQLLCRWMFASZIQ72EGRWGVFTCUJRY",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/T4VYQLLCRWMFASZIQ72EGRWGVFTCUJRY/",
    "sender": {
        "address": "bob (a) evoria.net",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Bob Stewart",
    "subject": "[amsat-bb] Re: Polarity Switcher Relay - repost",
    "date": "2007-09-05T19:48:28Z",
    "parent": null,
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "--- Bruce Robertson <[email protected]> wrote:\n\n> In your previous letter, you describe the antennas as \"turnstile on 2m and\n> a turnstiled moxon on 70cm\"; are these fixed, like the moxon Cebik\n> recommends, or are they rotating beams?\n\nActually, the 70cm is just like Cebik published in QST.  But, for some\nreason, I don't get as good performance on the 2m version, so I switched\nthat to a regular turnstile 3/8 wavelength above a layer of Reynold's\nWrap.  I've also managed to work a number of 2M SSB stations on\nthat antenna.  I don't have any rotators; they're just pointed straight up.\n\n> As you probably know, depending on the roofing material, you are suffering\n> a not inconsiderable loss on 70cm from the signal passing through the roof.\n> Last time I looked into it, I figured on about 2dB for my shingled wood roof.\n\nI didn't know how to figure this, but I figured it would be 1 or 2 db.  Winter\nsnow is going to be unworkable, of course, so the plan is to move them \noutside.\n\nOne of the biggest negative impacts I've had is when I added the 70cM brick.\nIt has about a 6db loss on receive and it took me awhile to figure that out.\n\n> If you are certain you don't want to try mode B, you could even get a\n> receive-only 70cm preamp, \n\nActually, I have made a handful of mode B contacts on both AO-7 and VO-52.\nI've just gotten kinda sidetracked with this 70cm polarization thing and I\nfigured anything I did that improved reception (other than using a preamp\nof course) would improve my mode B uplink.  I've listened to a few contacts\non AO-7 mode A recently, but for some reason, neither of my 2M antennas\nhas enough oomph to get me an SSB signal that I can hear - even with the\n80 watt brick turned on.  I'll get that worked out, eventually.  I really want\nto have some mode A QSOs using my KWM-2A on downlink.\n\n\n>On 70cm CW you can also try\n> LO-19, which has a booming signal. I find it easier to use these to assess\n> the effectiveness of an antenna than to use the FM birds.)\n\nI'll give that a try.  One of the problems I have is that I don't have anything\nto use as a baseline.  I recently found a very strong digital repeater on\n433.7xx and I used the signal from that every 20 seconds to discover the\namount of loss in my 70cm brick on receive.  Normally, for alignments, I use\nthe IF bleedthrough from my VX-5R in WFM mode.\n\n> Yep. I just worry that you're not getting enough out of the antennas you've\n> already built. Quite honestly, I'd rather spend an evening doodling on the\n> birds with my indoor 1/4w whip and a preamp on 70cm than with my outdoor\n> beam and no preamp!\n\nI'll squeeze everything out of the antenna I can and then I'll add preamps.\nBut, I really want to build them myself if I can get over the engineering/\nparts list issues.\n\n> However you proceed, *please* keep reporting your results to the list. I\n> think the best thing we can do as a group is support each other in\n> antenna-building and -experimentation. If you can demonstrate a reliable\n> station with attic antennas, I think you'll be breaking some ground for all\n> of us.\n\nWill do.  I've made a lot of contacts on the FM birds with my setup.  Of\ncourse that's just a callsign and a grid-square.  But, the thing about doing\nthis is that I've had to optimize everything, including squeezing the last bit\nof S/N out of this old FT-726R that I could tune for.  For that, I resorted to\nthe IF bleedthrough mentioned above and tuned for lowest noise.  But, I have\nto admit that the difference from that to max signal might have been only\nwishful thinking.  ;)\n\nBob - AE6RV\n",
    "attachments": []
}