Topband: Rain noise

[Mike Waters]

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 <mikewate at gmail.com> 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 <rodman at buffalo.edu> 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
>>
>
>