Re: Re: VLF: 8270.002

["Markus Vester" <markusvester@aol.com>]

Thanks Jim!

 

My antenna's effective height measured at LF is about 9 m. It will be slightly less at VLF due to increased shielding by trees, my guess is ~ 8 m, giving 77 microohms radiation resistance. Thus 0.3 amps would radiate 7 µW (EMRP) or 13 µW ERP.

 

Operating hours are a bit limited by politeness to the neighbours who have to bear the acoustical emission from the loading coil. The 8.3 kHz tone is not really loud but quite penetrant. Here are a couple of pics of the present setup, with the coil enclosed by two rubber bins and placed outside the window:

http://dl.dropboxusercontent.com/u/26404526/vlf_coil_at_window.jpg

http://dl.dropboxusercontent.com/u/26404526/vlf_coil_and_antenna.jpg

 

Good luck with your forthcoming experiments!

 

Best 73,

Markus (DF6NM)

 

From: hvanesce

Sent: Friday, February 07, 2014 11:08 PM

To: rsgb_lf_group@blacksheep.org

Subject: RE: Re: VLF: 8270.002

Markus,

 

Great signal, congratulations.

 

Was your ERP ~ 5uW?

 

I had hoped to be operational (RX and TX) with the new stable oscillator last weekend but work and other nuisances interfered. I hope to complete that work this weekend, and try your TX stabilization technique next week; all of your work in this area much appreciated.

 

73, Jim AA5BW

 

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Markus Vester
Sent: Friday, February 7, 2014 12:33 PM
To: rsgb_lf_group@blacksheep.org
Subject: Re: Re: VLF: 8270.002

 

Uwe, yes - the left channel picks up the electric field near the antenna, using a 20 cm piece of open wire (level about - 30dB at L1). Both generators are active: the test signal generator feeds the phase reference to R5, and the digimode terminal delivers the output to the PA through L5.

 

Lubos, I was positively surprised to see about 20 dB SNR on your excellent Apollon temple receiver.

 

Peter, I think the signal did leave a 10 dB dash in your 238 µHz window. Not sure about that 47 uHz pixel, but the two-hour transmission would really be  too short for that bandwidth.

 

No trace yet on Stefan's new window, but this may well be due to the midday propagation minimum which we have often experienced on 8970 before.  

 

Thank you all for the grabbers and comments!

 

Best 73,

Markus (DF6NM)

 

From: uwe-jannsen@kabelmail.de

Sent: Friday, February 07, 2014 2:06 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: Re: VLF: 8270.002

 

Hi Markus,

so you feed the left channel with your eradiated signs via a piece of wire ?

what abt the signal generator and the digimode modulator, is one of them switched off?

ga

Uwe

 

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Von: rsgb_lf_group@blacksheep.org
Gesendet: 07.02.2014 12:37
An: rsgb_lf_group@blacksheep.org
Kopie: paul@abelian.netcom.co.uk
Betreff: Re: VLF: 8270.002

---

 

oops - that should be 8270.002! Old habits persist ;-) 73, Markus

 

From: Markus Vester

Sent: Friday, February 07, 2014 12:30 PM

To: rsgb_lf_group@blacksheep.org

Cc: Paul

Subject: VLF: 8970.002

 

I'm currently running a short test on 8970.002 Hz from 10 to 12 UT, using SpecLab phase-locked to 1-pps. The antenna is swinging in the wind so the current is a bit variable (0.25 to 0.3 A), but the feedback scheme should keep the radiated phase steady. So far a good peak has become visible at OK2BVG.

 

Best 73,

Markus