Hi Dimitris,
Interesting. BTW, it's a long time ago that we read from you. You have
been VK1SV some years ago, right?
I remember your websites and experiments with some long wires laying on
the ground. I wish to have such a wide area for experimenting like you
have :-) Recently i searched for one of your websies where you described
an experiment using 2x 100m of wire, if i remember correctly. But the
page was not found. Can you tell me the link, if it is still existing?
Well, i see no advantage in a RX antenna when using such rods. Maybe you
can build a RX loop antenna a bit more compact but then it will be very
heavy and the air gap (changing with temperature and mechanical forces)
may affect the phasy stability.
For a TX antenna i see no advantage either. An AL value of 1 uH can be
reached with most high mu ferrite toroids...
However, maybe you could build a H field RX antenna for frequencies
below 1 kHz, something like http://www.vlf.it/romero3/ics101.html or
http://www.vlf.it/matteobruna/ULF_Induction-Coil.htm
73, Stefan
Am 12.01.2019 04:48, schrieb Dimitrios Tsifakis:
Hi LF group,
I have managed to acquire a few very large ferrite rods (36 cm x 10 cm
x 2 cm). The material is unknown but I managed to form a square
'toroid' with four of them (they are heavy so gravity was enough to
keep everything in place for a measurement) and I measured about 15 uH
for 4 turns at 0.1 MHz, which if I have done the calculations
correctly implies a relative permeability of about 1000.
The R of the impedance of the square loop was low (<0.2 ohm) at 0.1
MHz and it increased fast with frequency (170 ohm at 5 MHz!).
The question is, what LF/VLF experiment would you do if you had half a
dozen of these rods?
73, Dimitris VK2COW
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