Re: LF: AW: Beaconing on 8.79 kHz in QRSS

[Roger Lapthorn <rogerlapthorn@gmail.com>]

It was NATO AGARD papers (not AGAARD) that I was referring to.

Here are some other useful references to ULF/VLF system design and practicalities:

<http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?reload=true&arnumber=1138037>
<http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0640319>
<http://www.search.com/reference/Ultra_low_frequency#Earth_Mode_Communications>

73s
Roger G3XBM

On 22 February 2010 10:03, Roger Lapthorn <rogerlapthorn@gmail.com> wrote:

At this frequency, widely spaced, grounded electrode pairs are probably the best "antenna".  There are references to how these work in the literature (for example NATO AGAARD papers from the 1960s, available on the internet I believe) and on one of the German ham sites (DK8KW) - see http://www.qru.de/#vlf .

 

Don't expect great ranges: up to 10kms is a fair aim with modern signal processing technology and reasonable (amateur levels) available power. Project Sanguine achieved worldwide coverage to submarines at 76Hz (yes Hertz!) but used enormous power and antennas stretching for 100s of kms.

 

73s

Roger G3XBM

 

2010/2/22 Stefan Schäfer <schaefer@hst.tu-darmstadt.de>

Hello Horst,

That sounds really nice. If it would be easy to find some motivated OMs in the near field (31km) ;-), that would be an interesting field to test.

Yesterday i have thought about possible antenna configurations for that range and got the idea that one could use a forrest as an antenna tower. There, you could hang up 100s meters of wire, in series and in parallel. You do not need to have that area beside your house. Nobody will see the wire and nobody will care about it.
Since summer 2007 i have a horizontal loop antenna mounted in some trees on my hill with excellent results on all HF bands and also 160m. The loop has 130m and is mounted up to 12m above ground. Perfect matching from 160m to 10m with my symmetric tuner. I even tried matching on 2200m without a problem but with bad ODX results, of course. But if one would try 2x 10*100m on VLF, the ODX would be interesting...

JO30OT is abt 160km from JN49IS and thus a little far i think ;-)

What is your RX antenna and have you already catched some commercial VLF stations in that range? Are there some?

73, Stefan

PS: One can be sure that there will never be SSB operation ;-)

________________________________

Von: owner-rsgb_lf_group@blacksheep.org im Auftrag von Horst Stöcker

Gesendet: Mo 22.02.2010 09:29

An: rsgb_lf_group@blacksheep.org

Betreff: RE: LF: AW: Beaconing on 8.79 kHz in QRSS

Hallo Stefan,

there was a notice in Funkamateur 12/05, S. 1287, that in DL the range <9kHz is free.

I could not believe that so I asked the BNetzA and after a while I got a letter which confirmed that.

So there nothing you've got to do for getting a licence. You do not need one.

There is no limitation of technical parameters like bandwith or power.

Hard to believe in german, but obviously true.

My QTH is Siegburg JO30OT

Horst
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G3XBM    GQRP 1678      ISWL G11088