Stefan,
I saw this Youtube video of 4 big guys trying to bring down a kite
like yours:
http://www.youtube.com/watch?v=K7q34sw4XMo
I would love to try this but I live in an area densely covered with
tall trees, and it would be quite a drive to an open area where I
could launch an antenna (children's playground is not a good place for
a HV antenna!)
73 Warren K2ORS
On Thu, Jul 26, 2012 at 4:48 PM, Stefan Schäfer
<[email protected]> wrote:
> Hello Warren,
>
> Am 26.07.2012 19:39, schrieb Warren Ziegler:
>
>> Stefan,
>> I imagine that a LF or VLF small vertical is a relatively high-Q
>> circuit, how do you manage to keep the kite vertical in resonance and
>> matched while the kite bounces around in the wind?
>>
> Most of the time the kite was quite stable, i.e. the angle and so the C did
> not change significantly. The antenna current is stable within a 10% limit.
> When the wind was poor in some situations, the kite drops to a lower angle.
> Then the falling ERP is rather affected by the lower effective height than
> by the changing current. The current (say 1A on 8970 Hz) can easyly drop to
> 400 mA when the angle changes from 80 deg to 40 deg.
> One method is to compensate this by turning the variometer from time to time
> or you can use a working point of the variometer that uses a slightly to low
> L. Then the antenna current does not reduce when the kite falls (in certain
> limits of course). This is the case because the little generator that i used
> (up to 550 W RF power in the best times) can be seen as something like a
> constant power source. So if the kite falls then slightly, the working point
> moves to the peak of the resonance curve and the rotation speed is somewhat
> lowered. It was funny to observe this effect for many hours on the field :-)
> But normally the movement of the wire does not strongly change the antenna
> current.
>
> OK?
>
>
> 73, Stefan/DK7FC
>
--
73 Warren K2ORS
WD2XGJ
WD2XSH/23
WE2XEB/2
WE2XGR/1
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