Also, if the elements etc. are insulated from the boom, the arcing could be across the insulator(s).
73, Mike www.w0btu.com On Mon, Jul 9, 2018 at 4:12 PM, Mike Waters <[email protected]> wrote: > Hello David, > > You're not the first person to experience that! :-) > > The short answer is that there is likely an atmospheric voltage gradient, > causing a corona discharge (which is making the noise). A corona discharge > emanates from sharp corners or points; the voltage builds up until it can > discharge. If you can smooth or insulate those points, you can reduce or > eliminate the noise. > > It's possible that if you do that to the top antenna, the corona with then > appear on the lower one. > > You could try installing a mast with a grounded, microscopically-sharp > point at the top, extending above the top beam. One made from a thoriated > tungsten TIG welding electrode is about as good as it gets. (Forget that > brushing thing that looks like a chimney cleaner! IMO, the points of the > wires are both too close together and not sharp enough.) > > DISCLAIMER: I have not personally tried this, but I have knowledge and > experience in electron physics and corona discharge. > > Having said all the above, the noise-causing discharge instead could very > well be an arc, such as between the coax connector's inner conductor and > shield. > > 73, Mike > www.w0btu.com > > On Mon, Jul 9, 2018 at 5:19 AM, Rodman, David <[email protected]> wrote: > >> First, I want to say this topic is not necessarily topband related, so if >> anyone wishes to comment about my question, please do so privately so as to >> cut down on band width. Thank you. >> >> >> Very smart people live on this list and I want to reach out to them about >> my system as they may know something about this too. When it rains, the >> top 20m antenna hears the precipitation and the bottom does not. Is there >> a way to silence this situation? More info on request. >> >> >> Again, thank you. >> >> >> --- >> David J Rodman MD >> Assistant Clinical Professor >> Department of Ophthalmology >> SUNY/Buffalo >> >> Office 716-857-8654 >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband >> > > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
