Hi Folks,
First of all please let me introduce myself. My name is Des (M0AYF) and
am currently a qrp H.F. operator (just a hint of qro :-) with an interest in
L.F. I have only been on the mailing list for a few days since I only
learned of its existence quite recently.
If I may I should like to ask one very important and practical question, is
it possible to make contacts effectively at 160 kHz with a proposed antenna
which would only be about 25 feet high and about 50 foot long (horizontal
wire or "T" resonated against ground) as this is about as much as I could
ever manage within the garden of my town semi. In other words are there any
operators on the list who are currently working with an antenna system with
these sort of dimensions. If so I would very much like to hear from you. I
would sooner find out now if my proposed antenna is totally impractical for
this wavelength rather than much later on after building up the other
components of an LF station.
I have been reading the RSGB book "The LF Experimenters Source Book" (page
2.23) which describes a ferrite loaded 73 kHz antenna loading coil. I
propose to try something similar for 160 kHz which brings me on to the main
subject of this posting. The ferrite I intend to try will be salvaged from
some old PC switch mode power supply's of which I have many. Too many in
fact (according to the xyl :-( who insists I dispose of as many as possible.
I have around 70 of these units free for collection, all are failures and
have been condemned as "beyond economical repair" (mostly switching
transistor failures) but failed early in their working life so most of them
are very clean and dust free. The units strip down very easily and many of
the components (not yet failed) are re-usable, these include 12V brushless
motor fans with finger guard (good for cooling P.A. or PSU), the all
important ferrite cored transformer, 2 x 330 microfarad 200 v capacitors.
Fast recovery power rectifiers (low voltage) and various EMC filter
components including some yellow/white toroidal cores (about 1 inch dia)
which I have used up to 7 MHz as baluns. The cases also make good housings
for ham projects ;-) The bottom line is that due to pressure from the xyl I
have to get rid of these very, very soon, I could simply arrange for these
to go for scrap but hoped that they may find better use with some of you
chaps. If anyone living in the region of Gainsborough in Lincolnshire is
interested in the above then please drop me a line. Only one catch, you must
collect them yourself. Hi Hi :-)
Sorry for the bandwidth, I promise I will not make a habit of it. Best
wishes and 73's to all "lowfers".
Des.
Des Kostryca (M0AYF) G.Q.R.P. no. 9788
I.A.R.U. loc. IO93OJ W.A.B. SK89
Member of the N.B.T.V.A.
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