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Re: LF: DK7FC's 8th VLF kite experiment

To: [email protected]
Subject: Re: LF: DK7FC's 8th VLF kite experiment
From: wolf_dl4yhf <[email protected]>
Date: Sun, 24 Oct 2010 14:44:30 +0200
In-reply-to: <[email protected]>
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Hi Stefan,

You wrote:
>
> I have been 5 dB stronger than the Alpha stn on 11904 Hz at your location ;-)
>
No, not really stronger than the Alpha's. Because the resonant loop antenna has favourized 'your' frequency, and attenuated the HF stuff. The antenna itself is a slotted aluminum tube bent to a ring (=grounded shield), tube filled with 0.6 mm enamelled copper wire salvaged from TV's degaussing coils. Inductance about 45 mH, resonated with 4.7 nF + 1 nF + the FET's gate capacity. The loop is tapped with an 2SK369 "audio" JFET, phantom-fed through the coax. I didn't measure the antenna's FET-loaded Q yet.

Anyway, despite that, the SNR comparison is impressive !

73,
   Wolf  DL4YHF

(p.s. also nice reception of SAQ here, just a bit of QRN)

Am 24.10.2010 13:56, schrieb Stefan Schäfer:
Hello Wolf,

I have been 5 dB stronger than the Alpha stn on 11904 Hz at your location ;-) Have you thought that this will be possible? ;-)

73, Stefan

Am 23.10.2010 18:27, schrieb wolf_dl4yhf:
Stefan's 8970 Hz signal SNR was over 20 dB with 200 uHz effective receiver bandwidth, observed at DF0WD (rural area) with a small, resonant, active loop antenna hanging in a tree.

Screenshot here:

http://www.qsl.net/dl4yhf/grabber/2010_10_23_dk7fc_at_df0wd_200uHz_FFT.jpg


73,
  Wolf DL4YHF.





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