Re: VLF: DF6NM on 8970.002

[Markus Vester <markusvester@aol.com>]

The carrier was on air continuously from 20:26 to 6:36 this morning.

 

Thanks very much to Lubos, as well as to all other live grabber operators. As far as I can see, traces appeared at DK7FC, G3ZJO, OK2BVG, and Paul Nicholson.

Best 73,

Markus

 

-----Ursprüngliche Mitteilung-----
Von: Lubos OK2BVG <bvgbob@hotmail.com>
An: _RSGB_LF <rsgb_lf_group@blacksheep.org>
Verschickt: Mi, 28 Mrz 2012 4:24 am
Betreff: RE: VLF: DF6NM on 8970.002

Hello Markus, VLF!

Your signal is nice visible on my grabber in QRSS6000 and traces in QRSS600. In the 6000 window is evident, that we did our VLF QSO in time, when the noise conditions were not the best. 

I have written an article about our qso in Czech. It will be publised in a ham magazine "Radioamater", common known in The Czech and Slovak republic. Some hams would be encouraged to find VLF band by the report. :-)

73!

Lubos, OK2BVG

---

To: rsgb_lf_group@blacksheep.org
From: markusvester@aol.com
Date: Tue, 27 Mar 2012 17:22:42 -0400
Subject: VLF: DF6NM on 8970.002

It's a beautiful night! At 20:25, I have started up a straight carrier on 8970.002 Hz (DHO locked). If all stays well I will leave it on until after sunrise.

 

An interesting observation on the side: In the first few minutes, I drove the amp up to 400 mA antenna current. A little corona became visible near the ends of two of the three topload wires - it wasn't very bright, not unlike 3rd magnitude stars when viewed from the ground 10 m below. But the 9 kHz sound from antenna itself could be heard quite loudly, which is a potential cause for neighbourhood trouble.

 

Then I reduced the drive to 350 mA where the corona disappeared completely. So did the noise, the antenna became absolutely quiet! All that was left was a little noise from the coil in the dustbin on the balcony, and the transformer indoors. Thus the predominant cause for a squeaking antenna must be corona. The fact that it can be heard at 9 rather than 18 kHz demonstrates that the discharge must have an asymmetric dependence on the voltage polarity.

 

At the same time, wideband electrical noise on the nearby LF grabber antenna went down by 20 dB.

 

BTW If you like you can actually read my VLF frequency from an alias line on the LF TA grabber: It is created by the 24th VLF harmonic, intermodulating with DCF 77, thus appearing on 24 x 8970.002 - 77500 = 137780.048 Hz.

 

Best regards,

Markus (DF6NM)