Re: LF: CT<>ZL

[MarkusVester@aol.com]

Dear LF group,

late again, but nevertheless - congratulations to Ed's group, Sam, Mike and Bob on their fantastic LF DX results!

Marek and Brian,
- on the other hand, there might be some sort of focussing gain on an antipode path. There was an interesting paper on ELF propagation (ie. 76 and 82Hz) by P. Bannister and A. Fraser-Smith, showing a formula and a couple of measured data points confirming that:
http://www-star.stanford.edu/~acfs/82Hz.pdf

Of course the situation may be very different for our "short" LF waves, which would be less likely to stay in coherence over such distances. But then again, observing the NCDXF beacon network on 14100 kHz a few years ago, I found much more consistent reception of ZL6B around the day, compared to closer ones like VK6 and KH6 which were rather erratic.

73 de Markus, DF6NM


In einer eMail vom 13.04.2004 19:45:38 Westeuropäische Normalzeit schreibt brian@esoterica.pt: 

> If a significant dark path is necessary as it would appear from the recently reported captures of DCF39 in New Zealand, I postulate that it is not possible under "normal" conditions to achieve longwave communication over the ~20,000km.  However all is not lost as previous experience with 160m showed that sporadic but very infrequent communication was possible over this path and at signal strengths that need some explaining.
>
> Perhaps someone with better understanding of this phenomenon (and better maths than mine) could calculate the diameter of the effective "cone of silence" around diametrically situated stations and suggest a strategy to exploit whatever phenomenon assisted communication on 160m.
>
> Please discuss.