Hi Wolfgang,
Yes, i know about the optimum L/d ratio but i haven't such a Wasserfass ;-)
Cooling the coil by water inside is rather a joke i assume? :-P The high
epsilon r (81) would slightly decrease the Q. But it would be a good indicator
if the water in the water butt is boiling, than i should do a TX break ;-)
Yes, here is also snow again, very nerving!! But there is also strong wind :-)
But today i will spend time winding the new coil. It makes no sense to use that
heavy 50kg coil with bad Q :-(
Maybe the water butt is an idea but... ...but it may be a little expensive,
perhaps. Hm, ok, i will think about it... ;-)
73, Stefan
________________________________
Von: [email protected] im Auftrag von Wolfgang Büscher
Gesendet: Sa 06.03.2010 11:35
An: [email protected]
Betreff: Re: AW: AW: LF: Re: 9kHz noise level
Hi Stefan, Paul, and the group;
Nice to hear about the progress, and hope to catch some signals here
(one fine day) in JO42FD near Bielefeld.
Stefan, just one suggestion:
A 2 m long 25 cm diameter tube as coil form will tolerate high voltages,
no doubt. But it's not the optimum L/D ratio for maximum coil 'Q'.
Did you consider other 'plastic objects' like plastic barrels (in
German: Die grünen oder blauen 200-Liter-Regentonnen, die man in vielen
Baumärkten findet) ?
I have one of those things here, and iirc the material is polyethylene,
which is quite a good dielectric.. better than some PVC.
You could even cool it from the inside wall with water, if necessary ;-)
Greetings from snowy Westphalia,
Wolf DL4YHF .
Stefan Schäfer schrieb:
> Very nice Paul!
> I hope i can generate a peak outcoming of the noise in the picture ;-)
> Yesterday i have got a PVC tube with 25cm diameter and 2m long. Additionally
> i have bought 0,4mm diameter enameled copper wire, abt 6km in one piece (i
> can give back the rest). So today i try to wind the big L, abt 540mH! Than,
> the internal R will be abt 350 Ohm, not less but no problem. As said, the
> limiting factor will be the voltage at the wire...
>
> 73, Stefan/DK7FC
>
> ________________________________
>
> Von: [email protected] im Auftrag von Paul Nicholson
> Gesendet: Sa 06.03.2010 08:27
> An: [email protected]
> Betreff: Re: AW: LF: Re: 9kHz noise level
>
>
>
> Stefan wrote:
> > I plan to transmit on 8,9700 kHz...
>
> > during the test i make QSY of some Hz if the RXing station
> > has a carrier/line on this QRG.
>
> Here's a live spectrum for 8970 +/- 1Hz - resolution is 5mH.
> Amplitude calibration is only within a factor of two or so.
>
> http://abelian.org/vlf/nb.shtml
>
> > do you know other members in the VLF group who live near
> > frankfurt?
>
> Ich habe die Frage gestellt.
> --
> Paul Nicholson
> --
>
>
>
>
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