VLF: New coil for 8270 Hz

[DK7FC <selberdenken@posteo.de>]

Hi VLF,

Today was (is) a good day. For the first time i tested the new VLF coil 
on the antenna. The coil is built for 8270 Hz. The DC resistance is just 
230 Ohm! It is intended to run 700 mA. A 3 layer coil, each layer has 30 
turns, overlapping the last layer with 20 turns. So far it has 70 
layers. And the diameter is 0.25 m. So thats super compact and robust. 
About 50 hours of winding though!
In a first test i measured 230 mA RF current and the power supply showed 
0.94 A and 24.5 V. So that's just 23W including PA losses. Not bad at all.
However the resonance frequency is 8.607 kHz, and that's why the coil is 
back in the shack now, waiting for another 3 layers. But soon i will be 
there...
https://dl.dropboxusercontent.com/u/19882028/VLF/20161228_151854.jpg

73, Stefan