"GM-11F" is the identification on mysterious radiofaxes apparently coming from the Ukraine, perhaps the Russian Navy in Sevastopol, on 5103 and 7090 kHz USB. These have been seen in Germany for at least a year. Content is the usual marine weather information. One transmission occurs daily at 1430 UTC.
7090 kHz is in the 40 meter amateur band, but other Russian military stations also operate there. This includes one of those single-letter beacon clusters (ENIGMA designator MX). "D" (Sevastopol, 7038.7) and "C" (Moscow, 7039.0) are especially loud pretty much 24/7 in central Europe.