Best one yet.....
I have totally enclosed the dongle in a perforated aluminum screen and grounded it to the main RF ground, the antenna and mast have been grounded to the main RF ground, the signals look to be almost error free. Oh I have also used a clip on ferrite bead to the USB cable, this has cut down on stray noise from that.
But I'm out in the boonies, this could be a blessing for my location.
For those in an RF cluttered location then some sort of directional antenna may be needed, some type of antenna that can track the satellites with a good back shield may be the best for this type of area.