Re: LF: Re: MiniWhip antenna, fiber optic

[Dimitrios Tsifakis <dtsifakis@gmail.com>]

HI Stefan,

Owen, VK1OD, has done a similar experiment and has placed a video on
youtube. Have a look at his updated web page:

http://vk1od.net/antenna/PA0RDT-MiniWhip/index.htm

73, Dimitris

2013/7/8 Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>:
> another image of the TX:
> https://dl.dropboxusercontent.com/u/19882028/LF/DK7FC_fiber%20optic%20active%20dipole_TX2.jpg
>
> Am 08.07.2013 01:59, schrieb Stefan Schäfer:
>
> Hi all,
>
> OK, although it can't work (do you remember?!) i built an active antenna
> with battery supply and fiber optic output. The active part is a BF862. The
> circuit is quite simple:
> https://dl.dropboxusercontent.com/u/19882028/LF/DK7FC_fiber%20optic%20active%20dipole%20schematic.jpg
> It is a first idea for the schematic. Maybe i will change it later so that
> the gate is shifted to 9V/2. Just for first experiments. In various tests
> with the BF862 i found that it was necessary to add a ferrite bead directly
> in front of the gate to prevent VHF oscillations of the JFET.
>
> The TX is already working:
> https://dl.dropboxusercontent.com/u/19882028/LF/DK7FC_fiber%20optic%20active%20dipole_TX.jpg
> Yes yes yes, it is not truely symmetric and the capacity at source must be a
> bit larger than that of the leg connected to gate. Anyway it will be useful
> for some basic and interesting experiments.
>
> RX is ready tomorrow.
>
> 73, Stefan/DK7FC