Loading ...
Sorry, an error occurred while loading the content.
 

RE: [softrock40] Re: QRP DX with Softrocks - Loop antenna

Expand Messages
  • Steve Ireland
    Hi Brad With such a high-Q devices, I guess that it is a realistic possibility. Where a mag loop can fail is when the Q of the system is too low, owing to
    Message 1 of 12 , Jun 28, 2007

      Hi Brad

       

      With such a high-Q devices, I guess that it is a realistic possibility.  Where a mag loop can fail is when the Q of the system is too low, owing to problems with surrounding objects, the coupling loop, too small a diameter conductor, etc – ironically, if Jean Claude is getting this kind of problems, it probably that means the Q of his loop is REALLY high and it is very efficient!

       

      Vy 73

       

      Steve, VK6VZ

       


      From: softrock40@yahoogroups.com [mailto: softrock40@yahoogroups.com ] On Behalf Of Brad Thompson
      Sent: Wednesday, 27 June 2007 9:46 PM
      To: softrock40@yahoogroups.com
      Cc: 'jabauzit'
      Subject: RE: [softrock40] Re: QRP DX with Softrocks - Loop antenna

       

      At 08:41 PM 6/26/2007, Steve Ireland wrote:

      >G’day Jean-Claude
      >
      >I am guessing that PJ2 is pretty humid and the
      >level of this humidity will change greatly
      >between night and day – and at other times.
      >As magnetic loops are such high-Q devices, it
      >only takes minute changes in moisture levels
      >surrounding the antenna to put it off-tune/require re-tuning.
      >Vy 73
      >Steve, VK6VZ

      Hello, Steve and Jean-Claude- -

      I wonder whether, along with changes in ambient
      humidity, day-to-night thermal contraction of the
      loop tubing might exert an equally large effect
      on the loop's Q?

      73--

      Brad AA1IP
      FN33um
      >
      >
      >
      >
      >----------
      >From: softrock40@yahoogro ups.com
      >[mailto:softrock40@yahoogro ups.com]
      On Behalf Of jabauzit
      >Sent: Wednesday, 27 June 2007 8:18 AM
      >To: softrock40@yahoogro ups.com
      >Subject: [softrock40] Re: QRP DX with Softrocks - Loop
      antenna
      >
      >
      >
      >--- In
      ><mailto:softrock40 %40yahoogroups. com>
      href="mailto:softrock40%40yahoogroups.com">softrock40@yahoogro ups.com,
      >"Roderick Wall" <rwallmail@. ..> wrote:
      > >
      > > Hi Jean,
      > >
      > > Can you please give us some details on your magnetic loop antenna,
      >and is it a home made?
      > >
      >
      >Hi Roderick,
      >
      >You can see pictures of it at:
      ><http://www.geocitie s.com/jabauzit/ Magnetic_ Loop.html>
      href="http://www.geocities.com/jabauzit/Magnetic_Loop.html">http://www.geocitie s.com/jabauzit/ Magnetic_ Loop.html
      >
      >It is homemade with soft copper pipe - used for gas lines - the
      >diameter is a little small - around 10 mm. I use a dual stator
      >variable capacitor plus other capacitors in parallel/series to tune
      >just the 40m band. The power is limited to around 10W due to the close
      >spacing of the capacitor plates. I tried different types of coupling
      >as I experience a very strange phenomenon: the SWR changes between the
      >day and the night. The problem is not solved and as I just moved house
      >I did not try again.
      >
      >73 de Jean-Claude PJ2BVU

    Your message has been successfully submitted and would be delivered to recipients shortly.