Received-SPF: none (google.com: owner-rsgb_lf_group@blacksheep.org does not designate permitted sender hosts) client-ip=195.171.43.25;
MIME-version: 1.0
Message-id: <53A978CC.8010105@verizon.net>
Date: Tue, 24 Jun 2014 09:10:36 -0400
From: "stan, W1LE" <stanw1le@verizon.net>
User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101
 Thunderbird/24.6.0
To: rsgb_lf_group@blacksheep.org
References: <53A8AE53.3060504@gmail.com>
 <8D15DB1FF8A27AE-2018-717F@webmail-d249.sysops.aol.com>
In-reply-to: <8D15DB1FF8A27AE-2018-717F@webmail-d249.sysops.aol.com>
Content-type: multipart/alternative;
 boundary="Boundary_(ID_WgPoFlT7yDR5ULKCIZu2Pw)"
Subject: Re: LF: VLF in Canada
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org

This is a multi-part message in MIME format.

--Boundary_(ID_WgPoFlT7yDR5ULKCIZu2Pw)
Content-type: text/plain; CHARSET=US-ASCII; format=flowed
Content-transfer-encoding: 7BIT

Hello Markus,

Interesting post about your coil.
If you cut the bottoms out from the buckets,
would you have better convective air flow for cooling the coils ?
Like a chimney effect.

I am starting to think about 9KHz operations. An interesting challenge.

I could not get to the arced coil .JPG. Do you have a better web address ?

Stan, W1LE    Cape Cod   FN41sr


On 24-Jun-14 6:55 AM, Markus Vester wrote:
> Joe, good to read this!
> Regarding the loading coil, I would agree with Stefan that a large 
> multiturn air coil is the best option. A laminated iron core would 
> suffer from excessive eddy current losses, and the effect of ferrites 
> is limited by saturation and hysteresis losses.
> My 1.3 henry coil consumed 2.3 km of 0.4 mm enameled wire, using 7 
> buckets with 480 turns on each:
> df6nm.bplaced.net/VLF/VLF_110304-06/coil_legospacers.jpg.
> The advantage is that due to magnetic coupling between layers, you 
> will need less wire for a given inductance. And the inductance is 
> adjustable across a wide range, using spacers. Disadvantages are the 
> high electric field between layers limiting voltage capability, and 
> less effective heat removal from the inner buckets. Stuffing the 
> buckets too tightly into one another is surely not a good idea:
> df6nm.bplaced.net/VLF/pictures/arced_coil_140601.jpg
>


--Boundary_(ID_WgPoFlT7yDR5ULKCIZu2Pw)
Content-type: text/html; charset=UTF-8
Content-transfer-encoding: 8BIT

<html>
  <head>
    <meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
  </head>
  <body text="#000000" bgcolor="#FFFFFF">
    <div class="moz-cite-prefix">Hello Markus,<br>
      <br>
      Interesting post about your coil.<br>
      If you cut the bottoms out from the buckets, <br>
      would you have better convective air flow for cooling the coils ?<br>
      Like a chimney effect.<br>
      <br>
      I am starting to think about 9KHz operations. An interesting
      challenge.<br>
      <br>
      I could not get to the arced coil .JPG. Do you have a better web
      address ?<br>
      <br>
      Stan, W1LE    Cape Cod   FN41sr<br>
      <br>
      <br>
      <br>
      On 24-Jun-14 6:55 AM, Markus Vester wrote:<br>
    </div>
    <blockquote
      cite="mid:8D15DB1FF8A27AE-2018-717F@webmail-d249.sysops.aol.com"
      type="cite">
      <div style="FONT-FAMILY: arial; COLOR: black; FONT-SIZE: 10pt">Joe,
        good to read this! </div>
      <div style="FONT-FAMILY: arial; COLOR: black; FONT-SIZE: 10pt"> </div>
      <div style="FONT-FAMILY: arial; COLOR: black; FONT-SIZE: 10pt">Regarding
        the loading coil, I would agree with Stefan that a large
        multiturn air coil is the best option. A laminated iron core
        would suffer from excessive eddy current losses, and the effect
        of ferrites is limited by saturation and hysteresis losses.</div>
      <div style="FONT-FAMILY: arial; COLOR: black; FONT-SIZE: 10pt"> </div>
      <div style="FONT-FAMILY: arial; COLOR: black; FONT-SIZE: 10pt">My
        1.3 henry coil consumed 2.3 km of 0.4 mm enameled wire, using 7
        buckets with 480 turns on each:<br>
        df6nm.bplaced.net/VLF/VLF_110304-06/coil_legospacers.jpg.<br>
        The advantage is that due to magnetic coupling between layers,
        you will need less wire for a given inductance. And the
        inductance is adjustable across a wide range, using spacers.
        Disadvantages are the high electric field between layers
        limiting voltage capability, and less effective heat removal
        from the inner buckets. Stuffing the buckets too tightly into
        one another is surely not a good idea:<br>
        df6nm.bplaced.net/VLF/pictures/arced_coil_140601.jpg</div>
      <div style="FONT-FAMILY: arial; COLOR: black; FONT-SIZE: 10pt"> </div>
      <br>
    </blockquote>
    <br>
  </body>
</html>

--Boundary_(ID_WgPoFlT7yDR5ULKCIZu2Pw)--