[Lf] [Fwd: [Lowfer] Really big coils- VA3LK]

[Andre' Kesteloot]

Larry Kayser wrote:

> Paul es group.....
>
> >I wonder if anyone has tried building a really big coil out of CATV line.
> >I can easily be formed into 3 or 4 foot dia circles and even more. With the
> >right lenght to
> >dia. ratio yield a very hi Q coil.  The cable diameter .5" to 1.125" and is
> >relatively light.
> >
> >Might be OK for base loading.  Any ideas on this crazy scheme.
>
> I have tried using some black jacket aluminum shield coax here at the 4 ft
> diameter and I was not able to in the few hours I had to work on it make the
> coil perform.  I unrolled the coax and used it as a radial were it made a
> measureable contribution.  IF I have the sense right very high performance
> coils, Hi Q included are when the coil approaches square, diameter by
> length.  The Q seems to improve quickly when one goes to an odd number of
> vertical winding posts and creates what I think is called the basket weave.
> My next series of loading coils here will be LITZ wire on a basket weave in
> a square format with a small variometer at the top for screwdriver motor
> tuning under PC control.
>
> >Also has anyone heard VA3LK on 137.710.   I am very dissapointed that I
> >cannot hear/see him using
> >Spectran 4.0 and a 200 foot long wire.  I heard that there was a good
> signal
> >in Western PA and also that someone
> >1100 miles away recently copied him  I gotta be doing something wrong.
> >137.710 correct with 800 Hz  CW note?
> >Also no sign of his friend 14 Hz down.
>
> There are a number of issues for this, not sure of all of them but a 200 ft
> long wire is from my experience here a lousy LF receiving antenna.  My best
> results last winter were with a 1000, 2000, and 4000 ft Beverages laying on
> the ground, terminated in about 500 ohms and using copper pipes bashed into
> the ground - which is really horizontal under the soil and above the rock
> hi.  I have an email from a chap in Maine who copies the test signal on his
> speaker most of the time, his antenna is very significant, ie big.  From my
> meager experience it is essential to go through a very hard learning curve
> with this LF receiving bit, hearing weak signals is a complete layer of
> significant effort under the general listening on LF.
>
> I offer this hint.  I have a large coil and capacitor that is series
> connected on any broadband antenna to resonate on 137 kHz.  This assembly
> makes and amazing difference for weak signal reception.
>
> The last point was that I have learned that the use of the DSP programs Gram
> etc. need to be diddled a lot to get the last few dB out of them.  When I
> was looking for WA2XTF (AMRAD beacons in the Washington area) I spent months
> seeing a faint line that I came to know was them, the second signal 5 Hz
> away was similarly there but not readable (and it never has been readable
> here).  One after noon I looked up and there on the screen was the complete
> call sign.  The point of this comment is that I was near the threshold for a
> long time before I managed to pull them out of the mud.  My total of heard
> reports for the test transmissions from here on 137.710 is now over 20, I
> know this as I am making up the SWL/QSL cards for those who have been kind
> enough to send in reports.  I know that if you are not able to hear the NPG
> rtty on 135.95 at times that you will not hear me.  If you need the full
> data on NPG let me know I will get my log book and send you a summary of
> information on that signal.
>
> The VA3LK test signal on 137.710 continues at this time transmitting EVEN
> hours UTC with .4 wpm CW.  If you are having trouble identifying the signal
> I can send you a .jpg of what others are seeing so you can have a sense of
> finding the signal in the noise.
>
> 73
>
> Larry
> VA3LK
>
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