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UHF Follow-on & Inmarsat A monitoring

  • 19-04-2003 11:41pm
    #1
    Irishdude
    Closed Accounts Posts: 7 ✭


    Hi folks,
    I'm into designing and building satellite antennas and electronics etc..
    Does anyone here monitor Inmarsat or the UHF UFO birds??


Comments

  • #2
    telecinesk
    Registered Users, Registered Users 2 Posts: 617 ✭✭✭telecinesk


    Try here: http://ourworld.compuserve.com/homepages/pjmarsh/

    Think that should do.
    I used to listen....


  • #3
    Capt'n Midnight
    Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 92,550 Mod ✭✭✭✭Capt'n Midnight


    'cos then you can do two way stuff - license free.
    www.irishwan.org

    main problem with antenna design is it rains 4 days per week on average - so waterproofing is essential.

    Page with radio links http://www.cebik.com/radio.html
    DIY Radio Astronomy http://www.radiosky.com/ - may be links to sites with DIY radio telescopes

    Look up hams - many of the antenna designs will scale easily to UHF
    note:Yagis are still trial and error with many elements so they don't scale too easily.

    Keywords
    dicone colinear "phasing coils"


  • #4
    watty
    Registered Users, Registered Users 2 Posts: 32,417 ✭✭✭✭watty


    In scaling a Yagi you have to scale EVERY dimension with frequency,
    Even the boom diameter and rod diamater, as well as the obviousl element spacing and lengths.

    Also the rod length and spacing is affected by direct or insulated mounting of elements on boom, and if directly connected, even thickness of insulating spacer.

    DX UHF needs very good feed cable.

    UHF satellite / space stuff often needs circular polarised aerail (A regular aerial will receive either hand of circular, but at 6db less).

    A pair of crossed yaggi on one boom can be wired with a coax cable delay for either RH or LH circular polarised.

    A helical aerial is only RH or LH depending on direction of spiral and is much harder to make


  • #5
    telecinesk
    Registered Users, Registered Users 2 Posts: 617 ✭✭✭telecinesk


    Nice links.
    Pity Im not in Dublin anymore, the WAN thingy looks interesting.
    3hrs from Budapest puts me slightly out of range....
    Think theres wan here but I dont like to bother the locals too much..


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