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Date: Wed, 21 Dec 2016 14:13:49 +0100
From: DK7FC <selberdenken@posteo.de>
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Subject: Re: LF: ULF experiment: A MEchanical Based Antenna
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For a given antenna with its given antenna capacity and radiation 
resistance you will need a certain antenna current to radiate a certain 
power. To achieve this antenna current you will need to apply a high 
voltage, depending on the frequency and antenna capacity. You can 
generate this voltage in different ways.
My antenna capacity is in the order of 500 pF, which is relatively much, 
relative to average amateur antennas. At 2970 Hz, i have to apply 11 kV 
to get 100 mA and 1.2 uW ERP.

Now, generating 11 kV (and more!) on 2970 Hz is far from easy. Your 
transformer or coil or what ever arrangement has to withstand that 
voltage. Ferrites tend to saturate at such low frequencies and mains 
transformers are to lossy at this frequency, also their secondary 
winding does not hold the combination of high voltage and 100 mA (and 
more! :-) ).

73, Stefan

Am 21.12.2016 13:42, schrieb Martin Evans:
>
>
> Forgive me for asking what may be quite obvious to many - but does 
> this mean that if I spun a magnet at 8000rpm then I would generate a 
> 8kHz radio signal, identical in every way to an 8kHz signal generated 
> in a more conventional manner?
>
> If so, it sounds a lot easier than winding all that wire.....until the 
> magnet flew apart anyway!
>
> Martin  GW3UCJ  Swansea.
>
>>
>> ever heard of a "A MEchanical Based Antenna​" ?
>>
>> Me neither until today ;-)
>>
>> 73, Rik  ON7YD - OR7T
>>
>>
>

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For a given antenna with its given antenna capacity and radiation
resistance you will need a certain antenna current to radiate a certain
power. To achieve this antenna current you will need to apply a high
voltage, depending on the frequency and antenna capacity. You can
generate this voltage in different ways. <br>
My antenna capacity is in the order of 500 pF, which is relatively
much, relative to average amateur antennas. At 2970 Hz, i have to apply
11 kV to get 100 mA and 1.2 uW ERP.<br>
<br>
Now, generating 11 kV (and more!) on 2970 Hz is far from easy. Your
transformer or coil or what ever arrangement has to withstand that
voltage. Ferrites tend to saturate at such low frequencies and mains
transformers are to lossy at this frequency, also their secondary
winding does not hold the combination of high voltage and 100 mA (and
more! :-) ).<br>
<br>
73, Stefan<br>
<br>
Am 21.12.2016 13:42, schrieb Martin Evans:
<blockquote
 cite="mid:b6ace890-c740-d217-6b34-88a41a3caaef@mollies.freeserve.co.uk"
 type="cite">
  <meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
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Forgive me for asking what may be quite obvious to many - but does this
mean that if I spun a magnet at 8000rpm then I would generate a 8kHz
radio signal, identical in every way to an 8kHz signal generated in a
more conventional manner?<br>
  <br>
If so, it sounds a lot easier than winding all that wire.....until the
magnet flew apart anyway!<br>
  <br>
Martin  GW3UCJ  Swansea.<br>
  <br>
  </div>
  <blockquote cite="mid:1482320831911.81165@kuleuven.be" type="cite">
    <p><br>
    </p>
    <p>ever heard of a "<span style="font-size: 10pt;">A MEchanical
Based Antenna</span><span style="font-size: 10pt;">​</span><span
 style="font-size: 10pt;">" ?</span></p>
    <p><span style="font-size: 10pt;">Me neither until today ;-)</span></p>
    <span style="font-size: 10pt;">73, Rik  ON7YD - OR7T</span>
    <p><span style="font-size: 10pt;"><br>
    </span></p>
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