FWIW
This is where a lot of the confusion about "charge dissipators" (porcupines,
for example) for lighting reduction comes from.
On Wed, 17 Dec 2025 22:28:04 -0800, Michael Tope <W4EF@dellroy.com> wrote:
This is an excellent explanation, Jim. I was hoping you would chime in
and help clarify the confusion. I've read the arguments about why
grounding Yagi elements won't help with rain static, but I always found
the explanations wanting. Yours is a very clear explanation of the
distinction between that phenomenon and the kind of static buildup that
Jack W6FB was describing.
If it isn't already in there, this would be something useful to include
in the ARRL Handbook or ARRL Antenna Book.
73, Mike W4EF.......................
On 12/17/2025 9:44 AM, Jim Lux wrote:
>
> Enlarging on this a bit - They are all examples of charging by particles
> hitting or coming near something. Whether it's wind blown dust, snow, or
> ice, or raindrops, etc. And whether the charge got on the particles by
> induction, tribocharging, or other sources.
>
> There's two notorious effects - one is that "the antenna gets a charge" -
> which a static dissipation choke/resistor/whatever will fix. Same for open
> telegraph or telephone lines. one of the spectacular forms of this is the
> "glowing tips" of helicopters in dust storms, but it also occurs on airplane
> props, etc. And, of course, charge accumulating on the airplane body. In
> planes, you discharge it with sharp points to force corona to form and bleed
> off the charge gradually.
>
> The other effect is where *something other than the antenna* gets charged,
> and periodically it breaks down with a spark or corona brush, discharging it.
> Basically a relaxation oscillator. That's the one that makes the buzz or
> whine. Since the spark is wideband, you're hearing it in your receiver as a
> sort of discrete noise source. Obviously, nothing you do to your antenna
> will do anything about that.
>
> There is an interesting case reported (I'll have to look for it) where there
> were two structures that would get charged, and the charge interacted, so
> that caused a changing frequency of discharges (since the relative voltage on
> the two objects affected the charging rate in the relaxation oscillator,
> which changed the rep rate of discharges). You can create something like
> this artificially with a Van deGraaff generator and some suitable spheres (to
> hold charge) and spark gaps. Or, with a machine that unspools plastic
> sheeting from one roll to another (to make precut lengths) - That one was
> quite impressive, because the charging current was impressive (milliamps).
>
> I'm not sure how you'd fix this kind - unless you have control over the
> structure AND there's a way to dissipate the static in a "non-periodic" way
> (i.e. have lots of sharp points, to turn it into a steady hiss of corona -
> e.g. christmas tinsel on the sheet rolling machines).
>
> Interestingly enough St. Elmo's fire isn't actually corona from the objects.
> It's a bit more complex - what happens is that the object is wet, and the
> field builds up creating electrostatic forces that tend to "spray" particles
> off the tip. Those particles are charged, often with sufficient charge that
> the surface field is > 3MV/m breakdown of air, so it's the particles that are
> glowing, not the object. The other thing is that charged water droplets start
> to evaporate, so the radius gets smaller, but the charge remains the same, so
> the surface field rises, leading to corona at the particle surface. Salt
> water works better than fresh. You can set up a demonstration if you have
> something like a 50kV DC supply - put a tray of water with a cork or piece of
> wooden dowel standing up in the tray that's wet. Put a flat electrode above
> the cork (at least an inch or so, you don't want regular breakdown), and
> connect the power supply between tray and electrode. Styrofoam cups work
> well as supports for the upper tray (which needs a rolled edge so you don't
> just get corona off the edge of the tray- I use foam covered by aluminum foil
> tape for this kind of thing) In a dark room, you'll see St. Elmo's fire
> surrounding the top of of the cork - it's pretty impressive and it "looks
> different" than regular old corona. Corona tends to have a sort of branched
> fuzzyness that is little leaders coming off discrete points, while St. Elmo's
> is more of a glowing cloud. Hard to describe, and I've not been able to get
> a good picture of it, but once you see it you'll know they're different.
>
> BTW, there is a theory that dust devils on Mars glow from corona discharge
> from the charged dust particles. There is a famous paper by Renno that
> reports glowing sand blowing off the tops of dunes at White Sands National
> Park. I think there was recently some sound recordings that seem to confirm
> this, but it's not imageable with the current sensors.
>
>
>
>
> On Tue, 16 Dec 2025 22:18:12 -0500, wrote:
>
> I did not think that a static drain would help precipitation static but I was
> curious what experiences others have had. It would be nice if it really was
> that simple. Below is what w8JI wrote on the subject:
>
> "Despite having grounded antennas and the same rain or precipitation striking
> physically identical antennas, the highest antennas are always noisy and the
> lowest antennas are always the quietest. This occurs on a variety of antennas
> and in a variety of systems. Antennas with grounded elements and antennas
> with insulated elements all behave in similar ways. Antennas near the top of
> towers, especially those without taller towers nearby, all have severe
> p-static in storms. Lower antennas show very little noise under the same
> conditions, even though they are being struck by the same particles.
>
> The cause of noise most commonly called p-static or precipitation static is
> obviously not from charged particles striking the antenna. While some of this
> might occur under some conditions, the overwhelming cause appears to be
> corona discharge from protruding points into space around the antennas or
> antenna structures. On dark nights with closing storms, I can look at my
> upper 40-meter Yagi with binoculars and see a
> fainthttp://en.wikipedia.org/wiki/St._Elmo's_fire from the element tips. This
> is similar to what I saw on the VHF antenna that noised-up during foul
> weather. Sailors have seen it on salt-water soaked wooden masts, and we are
> plagued by it also. We just have not paid enough attention to the evidence
> and have missed the real root cause. We consider it particles striking the
> antenna was nearly all cases appear to be the simple phenomena known as St.
> Elmo's fire.
>
> We can't cure precipitation static, but it can be reduced through the
> following steps:
> • Having something else much taller than the receiving antenna close to the
> receiving antenna or lowering antenna height.
> • Avoiding sharp points on or near the antenna. Sharp points increase voltage
> gradient and increase corona.
> • Avoiding protruding elements. Protruding elements increase corona.
>
> As a general rule the following makes little difference:
> • Grounded elements
> • DC shunt elements on feed lines
> • Improving ground systems or grounding"
>
>
> John KK9A
>
>
> From:ve6wz@shaw.ca
> Sent: Tuesday, December 16, 2025 8:58 PM
> To:john@kk9a.com; Jack Brindle
> Cc:towertalk@contesting.com
> Subject: Re: [TowerTalk] Static Drain Resistor in Arrestor
>
> Jack,
> "P-Static" (precipitation static) is a different phenomena that "wind static".
> A grounded antenna will NOT prevent P-Static. W8JI is correct.
>
> Wind static can build incredible voltages (I've seen it) and will discharge
> to ground. Grounding the element through a choke or high value resistor will
> eliminate this. All my antennas must have this.
>
> Precipitation static is a different thing. This is that screeching, buzzing,
> even whistling sound that will crescendo and sputter out, only to start again.
> Its the noise that when happening will shut you down from operating.
> It happens when a storm is approaching or in effect. I hear it all the time
> during rainstorms and even snowstorms.
> Grounding the elements on your Yagi or verticals make NO difference at all to
> this type of static.
>
> I really don't think precipitation static is well understood regarding how it
> develops and the exact mechanism that triggers it, but a google search might
> give you some background.
>
> Either way, a static drain choke or resistor will NOT eliminate this type of
> noise when it happens.
>
> Steve ve6wz
> ________________________________________
> From: TowerTalk on behalf of Jack Brindle via TowerTalk
> Sent: Tuesday, December 16, 2025 4:06 PM
> To:mailto:john@kk9a.com
> Cc:mailto:towertalk@contesting.com
> Subject: Re: [TowerTalk] Static Drain Resistor in Arrestor
>
> Yes, it definitely helps with rain static. If W8JI actually stated that
> grounding the elements doesn’t help, he was wrong.
> It is important to bring both sides to ground, and together, usually through
> a large value resistor or RF Choke that will handle the power. Tieing both
> sides of a dipole through this to ground provides a path to bleed off the
> static charge, thus eliminating rain static (and snow static, etc). As Wes
> stated, adding a fairly large resistor across the dipole insulator really
> helps. Then timing that to ground through the arrestor finished the job.
>
> 73,
> Jack, W6FB
>
>
>> On Dec 16, 2025, at 5:48 PM,mailto:john@kk9a.com wrote:
>>
>> Does the Morgan coaxal arrestor help with precipitation static or just the
>> arc noise? Rain static can be brutal when contesting. I thought mine might
>> be related to using OWA designs with insulated elements but W8JI has stated
>> that grounded elements make little difference.
>>
>> John KK9A
>>
>> Ron WV4P wrote;
>>
>> My fullsize 4el 40 with cool dry air wil arc several inches from coax tip
>> to ground from static. With the Morgan M303 inline... Nothing. This was
>> also very apparent on the SDR (Flex) screen from what looked like lightning
>> static crashes to.. Nothing. In that respect, they did exactly what they
>> claimed.
>>
>> Ron, WV4P
>>
>>
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