Hi all just joined and don't usually "do" forums but thought I would this time. I guess many out there have had trouble with the aerial on the roof catching on garage doors. I thought I would invest in a shorter one but not sure which to get. Has anyone any experience in purchasing a reasonably priced one which works perfectly well? There seems to be a few on sale at various outlets but with different thread sizes and what have you I'm now not sure. Would appreciate advice.