I've been suffering local qrm on 2m for a while, I think it's something like plasma tv or an accumulation of other domestic gear, it makes noises wandering about the band burbling and sounding like someone blowing a rasberry ! (and sounding like a buzz in fm mode).
As the driven elements on the ZL specials are 'floating' I wondered whether they were picking up noise so decided to try out putting an earth strap to the boom from the mid point of the back side of the loop. Being balanced I reckoned that it shouldn't affect the rf operation so have just done it on one so far, and there are signs that there is less noise. I can now make up 3 more and put them on the other driven elements in the 7 over 7 pair. There's no noticeable change in swr, still under 1.2 and can still hear PE7CIS beacon @ 631km !.
As the driven elements on the ZL specials are 'floating' I wondered whether they were picking up noise so decided to try out putting an earth strap to the boom from the mid point of the back side of the loop. Being balanced I reckoned that it shouldn't affect the rf operation so have just done it on one so far, and there are signs that there is less noise. I can now make up 3 more and put them on the other driven elements in the 7 over 7 pair. There's no noticeable change in swr, still under 1.2 and can still hear PE7CIS beacon @ 631km !.