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Radio Australia Special Event or would you like to try a 20db HF antanna?

Discussion in 'Contests, DXpeditions, QSO Parties, Special Events' started by VK3ZYZ, Feb 11, 2020.

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  1. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    RadioAustraliaSpecialEvent.png


    This is an upcoming one off chance to try a ham radio transceiver on the antennas at Radio Australia, Shepparton, before it is completely demolished.
    Have you ever wondered how a 20db HF curtain array would work?

    Watch http://www.sadarc.org/index.php/radio-australia-special-event/ for updates. Registrations for a space will open soon.
     
    UR5GAW, YF8RQN, N0TZU and 1 other person like this.
  2. WW2PT

    WW2PT Ham Member QRZ Page

    I grew up listening to RA in the wee hours on 31m. It’s so sad that they were shut down. It feels like part of my childhood has been erased. :(
     
    N0TZU likes this.
  3. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    Yes, I feel it is a stupid decision. And the equipment is being scrapped so it cannot be started up again. Very sad indeed.
    I am a bit biased as it was my work place for almost 20 years. But I have not talked with anyone who thinks it is a good decision.
     
    K5SLO and WW2PT like this.
  4. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    Attached Files:

    Last edited: Feb 14, 2020
  5. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    The registration is now active :)
    Note the address change......
    http://ra.sadarc.org/
    Please feel free to register a place if you want to participate in this historic event.
    And pass the info around so all can know about it. If you are not able to attend in person, maybe you would like to take part in the "other end" of the contacts.
    And the times mentioned are Australian Eastern Daylight Saving Time.
     
    K0UO likes this.
  6. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

  7. SM0AOM

    SM0AOM Ham Member QRZ Page

    The crew-members that eventually will man the station are in for an experience.

    Some 10 years ago, a group of radio amateurs managed to "borrow" the Hörby transmitting site for Radio Sweden International shortly before the transmitting equipment was sold as spare parts and the antennas were demolished.

    There were a total of 5 curtain and log-periodic antennas available with gain figures in the 14 to 23 dBi ranges.

    As the site had belonged to my previous employer, I was invited to the event.

    For a week-end, multi-operator multi-transmitter operations on the 7,14,18 and 21 MHz band, using 1 kW transmitters were made with very good results.

    Some pictures:
    [​IMG]
    Antenna farm with 600 kW Allgon Log-periodic in the foreground

    [​IMG]
    TCI curtain antenna


    [​IMG]
    The 600 kW Telefunken antenna matrix

    [​IMG]
    Connection of the 1 kW feed-line by alligator clips

    [​IMG]
    Overview of the antenna direction selection from the control room

    [​IMG]
    Group photo of the participants


    73/
    Karl-Arne
    SM0AOM
     
    UR5GAW, N0TZU, K0UO and 1 other person like this.
  8. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    YF8RQN and K0UO like this.
  9. VK3OT

    VK3OT XML Subscriber QRZ Page

    Glad to be part of a special event and I am bringing my MORSE Key for 40m USA, I watched the ABC wrap up of RA and could see there will be no coming back, 400 houses will fit in that block worth billion$, sadly.
     
    K0UO likes this.
  10. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    That would be fun to work with my European Distributed Fed Curtain which also has about 18 to 20 DB

    KOU Rhombic Antenna Farm is located at the Kansas QTH with over Two miles of Wire in the Air & On the Air, “The RF Gotta-Go-Somewhere"!

    73
    K0UO/V31KW
     
    VK3YNV likes this.
  11. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    UPDATE:
    The 50 to 300 Ohm BALUNs have been installed and tested ready for the event.
    All the antennas that we are planing to make available for use have been disconnected from the switch and wired to a BALUN.

    BALUN_1 copy.jpg

    BALUN_2 copy.jpg

    These BALUNs work pretty well.

    Here is the test setup....
    There are 2 x 50:300 ohm BALUNs in series to give 50:50 ohms. The Codan 8525A is the test source.
    upload_2020-3-2_16-28-58.png


    Starting temp plus a few mins, = 27.4C

    upload_2020-3-2_16-30-59.png
    VSWR is pretty good!


    upload_2020-3-2_16-33-19.png
    Around 70W in, and 65W out. This is via the 2 BALUNs in series.
    32.2C after 20 mins carrier.
    (Note the "IRWIN" brand tune button operator :)
    It was easier than holding a finger on the button!


    Construction info is here...
    https://ra.sadarc.org/#!/baluns
    An addition not shown in the construction article is the Earth connection that each BALUN now has to make sure all the antennas are safely tied down for static protection.
    My legs are sore from being on the ladder for long periods of time!
     
    UR5GAW likes this.
  12. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    Just a bit over 2 days to go!
    This is all starting at ....
    00:00:00 Saturday March 14, 2020 in Australia/Victoria
    13:00:00 Friday March 13, 2020 in GMT

    There will be streaming audio of the contacts available (if everything works ok) so folks will be able to listen in on line.
    Just keep checking the web site for updates.
    https://ra.sadarc.org/#!/

    http://www.sadarc.org/ has a few historical photos.
     
  13. WN1MB

    WN1MB Ham Member QRZ Page

    Roger those wee hours!

    I remember sitting in the basement shack tuning in my prized Collins R-392 for Radio Australia for the first time. And just above the noise floor I could hear "Waltzing Matilda." It was a very, very special time, place, and event. Save Alzheimer's or other dementia, it's a memory I'll long cherish.
     
    K5VZD and WW2PT like this.
  14. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    It is just after 8PM on Friday night here and I'm home for a quick bite then back to RA.
    At this time some test transmissions are being made to make sure the antenna switching and power supplies etc. are all working.
    Keep a listen out on all HF bands as it is up to the individuals where and what mode they use.
    Just under 4 hours to go al I hope it all works!
     
  15. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    It is now just after 2AM Sat 14th here.
    And I have had my first overseas contact, Mike, WA3O on 7.162 (I think it was) and it turns out my transceiver was only outputting 25W or there abouts.
    Then a contact with Bob, KE0AHKM and another with Perry, KG7YC on 7.670.
    Thanks fellows!

    Details of my set are here... http://www.sadarc.org/Projects/Hawk 102-12.pdf
    It was purchased from a junk store for $30 and an Arduino driving an Si5351 "vfo" was added.
    It is pretty amazing what a 17db gain antenna can do!
    I am off to bed. It has been a huge day.
     

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