Re: VLF: EbNaut on 2 frequencies

[Markus Vester <markusvester@aol.com>]

Very interesting! Noting the steep dip near 200 km, which seems to be in line with the observed lack of nighttime (as opposed to daytime) signal at DL0AO. Could you perhaps also produce a similar plot for local noon?

Best 73,
Markus (DF6NM)



-----Ursprüngliche Mitteilung-----
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Di, 17. Okt 2017 18:41
Betreff: Re: VLF: EbNaut on 2 frequencies

I ran my homebrew propagation model on the great circle from
DK7FC in direction of Todmorden.

Here's the received signal for the two frequencies,

http://abelian.org/vlf/tmp/171017c.gif

given 200mA current and antenna effective height of 20m.

Todmorden is at 881 km and the rxed flux density is

6430 Hz: 0.032fT
6510 Hz: 0.046fT

so 6510 is about 3dB stronger than 6430.

The model uses the international reference ionosphere

https://en.wikipedia.org/wiki/International_Reference_Ionosphere

and takes account of date, time and bearing. It is ray tracing
ground wave and in this case up to 18 hop sky waves. Actually
12 hops seems enough.

--
Paul Nicholson
--