> Date: Mon, 10 Mar 2014 22:07:43 +0000
> From: [email protected]
> To: [email protected]
> Subject: Re: LF: Daytime 29.499 kHz
>
> A better signal last night from WH2XBA/1 and I was able to go
> back to using 10 minute averages to improve time resolution
>
> http://abelian.org/vlf/tmp/29499_140310a.gif
>
> 120 deg phase change as usual but taking till 04:00 to complete.
> S/N here was good between 04:00 and 08:00 thanks to background
> subsiding.
>
> Now four days comparison with NAA
>
> http://abelian.org/vlf/tmp/29499_140310b.gif
>
> The first 3 nights were opera but last night was carrier until
> 04:00 and carrier would be sqrt(2) times stronger than opera.
>
> Yes it is possible for winter day maximum to exceed that
> of summer on certain paths. There is no simple rule to say
> which path.
>
> For example DHO at 23.4kHz to Todmorden (646 km)
>
> http://abelian.org/vlf/tmp/dho_2013a.png
> http://abelian.org/vlf/tmp/dho_2012a.png
>
> Propagation is complicated at short range because there are
> many modes (or combinations of rays with different number
> of hops if you visualise things that way) contributing to the
> total signal. When calculating signals by ray tracing it is
> usually necessary to include paths with up to 12 or 15 hops
> at least, in order to get a model that resembles a real diurnal.
>
> --
> Paul Nicholson
> --
>