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6 Meter/50mhz Magnetic Loop For FT-8 And More

Discussion in 'Amateur Radio News' started by KJ4YZI, Dec 8, 2017.

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  1. W1YW

    W1YW Ham Member QRZ Page

    IOW its a capacitor subject to voltage arcing and the problems of using an 'air' dielectric. Hey, why use a substrate dielectric when you can eake out such compromised power with air alone?

    Christmas....when you guys discover 'FR4' let me know.
     
  2. AK5B

    AK5B Ham Member QRZ Page

    If and when Bob implements a vacuum variable option for his finely-crafted loop we'll certainly let you know---we wouldn't want to let down the nurturing side of our "community" now, would we?

    Give Bob a break---he deserves better for coming up with something that will particularly appeal to the QRP, digital and SOTA enthusuasts---among others. As he stated earlier, he did this primarily as a learning experiment and one that would inspire hams to tinker and DIY antennas.

    Hope he sells plenty!
     
    KD7CAC and ND6M like this.
  3. W1YW

    W1YW Ham Member QRZ Page

    Well then be prepared for alleged 'antenna gurus' in ham circles saying things like 'STL's are like the copper bracelets of medical devices'.

    But I'm game: let's say there's this new tool of making STL's from CNC's.... sincerely now: where do you go with it? What additional experimentation does it enable? What else do you learn by this? What can you do that you couldn't do before? How does this, in the US, meet the mission of Part 97?

    Unlike the abuse I have sustained, I am not inveighing such an attitude. I am asserting that you always have to ask: 'what problem am I trying to solve'?

    A major point to consider is that thick loops are preferred when --very small-- loops are used as STL's, because this cuts down the ohmic loss. I doubt very much that at this diameter, on 6M, you need a thick loop such as this. It may look nice, but what RF purpose does it serve? For example, a 20M scaled version of this would be a whopping 63-65 inches. And I will let you figure out the thickness when it scales.

    73
    Chip W1YW
     
    Last edited: Dec 12, 2017
  4. W1YW

    W1YW Ham Member QRZ Page

    Too expensive. Don't need it. See I3VHF's solution for high power.

    VE3UK should make the loop smaller so that you can put it, flat, in a backpack.
     
  5. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    No. They only interact with magnetic fields in the very near field in the same plane of polarization. The flip side of this is that they don't interact with noise sources in the near field of opposite polarization. This is the reason they are often claimed to"reject noise" or that they are "quieter".

    Tom, W8JI discussion.
    https://www.w8ji.com/magnetic_receiving_loops.htm

    https://www.w8ji.com/radiation_and_fields.htm
     
    AK5B likes this.
  6. AK5B

    AK5B Ham Member QRZ Page

    OK, I concede---those are all good rhetorical questions to pose---after mulling it over I think I was simply bowled over by the CNC loop's elegant beauty more than anything else. If I had and could use a TIG welding set up I'd probably be making the larger aluminum versions like VE3UK has been doing as well as Cirro Mazzoni. Their art in that mode amazes me.

    True, though, there is nothing really new under the sun.

    73,

    Jeff
     
    KD7CAC likes this.
  7. W1YW

    W1YW Ham Member QRZ Page

    BUT there could be....that's the point.

    It is very elegant. I suggest that VE3UK come up with a smaller one that fits flat in a backpack. Come up with a cool flat cap design as part of that... 6M FT8 SOTA is very intriguing...no one wants to carry a loop that takes up too much room or is in need of mechanical support...a FLAT embodiment, stiff, heck: that is a great idea.
     
    AK5B likes this.
  8. I8QJU

    I8QJU Ham Member QRZ Page

    video, excellent explanation.
     
  9. WO2E

    WO2E Ham Member QRZ Page

    ft8 is going crazy now is the new toy in town. i had never operated on 6 meters in over 40 years on the radio. im giving it some serious thought now. i will keep this loop in mind.
     
  10. MM6ECO

    MM6ECO Ham Member QRZ Page

    I think loops are amazing! Being licensed to 10Watts I purchased an alexloop but over time I have made a few loops myself. The capacitor is the most important item to get right!
    A good capacitor with good gaps works better than the capacitors that are tight together. At 10W this is not really a problem but higher power it`s very important...
     

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