I am seeing transmissions from the same station on different frequencies at the same time .. see example below

1146 -29 2.0 7.040035 0 F4GNS JN07 37
1146 -14 1.9 7.040085 0 F4GNS JN07 37
1146 -29 1.9 7.040134 0 F4GNS JN07 37
1146 -27 1.8 7.040184 0 F4GNS JN07 37

Is it the transmission which is creating the other signals at 50 hz gaps .. or is it my receiver/computer that is doing it ?

Doesn't happen with every received signal ..

Edit ..

I guess it's my kit .. nobody else seems to be reporting the like .. .. my interface uses a USB sound card that I paid 0.75 UKpound (including shipping) from Hong Kong .. maybe I'll lash out and get one a bit more expensive.

But then again, at the moment I am only getting it with F4GNS .. all others are OK