LF: Re: 137 kHz groundwave

["Alan Melia" <alan.melia@btinternet.com>]

Hi Stefan it may be daytime but both of those paths will be skywave even in
daytime at your power levels. Skywave and groundwave are about the same
starength at about 700km acording to all the papers. Dont forget the
waterfals are very non-linear it only takes about 3dB change in signal
strength to go from T to O+++, also you are seeing S/N which may be higher
in 4X4 although I got a rumble overhead a few minites ago and the rain was
horizontal.

Alan G3NYK

----- Original Message ----- 
From: "Stefan Schäfer" <schaefer@iup.uni-heidelberg.de>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, May 26, 2011 1:51 PM
Subject: LF: 137 kHz groundwave


> LF,
>
> I just sent some CQ calls on 137.71 kHz and saw the signal at about the
> same strength on the G4WGT grabber in 910 km, O copy. But there is no
> trace at all on the YO/4X1RF grabber in 1426 km (in QRSS-10). The 137
> kHz groundwave seems to "stop" somewhere between these distances, maybe
> arround 1000km.
> I'm sure some of you have some better theoretical and/or practical
> experience about that?
> Another advantage of VLF,where it's "easy" to reach 2500 km and above
> anytime :-)
>
> 73, Stefan/DK7FC
>