[TowerTalk] Precipitation static

[David Robbins]

Well... the corona itself won't damage the receiver.  but... the center conductor of the coax connected to the antenna at the top of the tower will be at the same voltage as the antenna relative to the ground at the base of the tower or at the shack.  Important note, measuring a voltage always requires 2 points, a reference and a measurement point, in many cases the reference is implied, with lightning or other ground related measurements you must specify the reference point or the value is meaningless.  That said, since the voltage from the shack to the top of the tower can be very high, if there is nothing to equalize the center conductor and shield/ground voltage (assuming of course that the shield is connected to the radio chassis which is also connected somehow to ground), yes you could damage a receiver.   However, most kinds of filters, lightning arresters, static bleed resistor or coil, tuner, or anything else that has a path to ground at the shack end 'should' equalize this and help protect the receiver.

An antenna may provide more points for streamers to be initiated to complete the path to the downward leader, though if the leader coming down from the cloud is that close its probably going to hit the tower one way or another.  with the antenna at the top of the tower it is more likely the antenna will be hit than stuff below it on the tower... but it is possible to hit the side of a tower or building.

Also an aside about 'past performance not being an indicator of future performance'....  analyzing lightning strokes if full of all sorts of statistics, I do that as part of my job.  not getting struck for years, or getting struck and not getting damage, is no indication that you are safe over any future period.  Lightning stroke density and current is extremely variable, so much so that we recommend using at least 10 years worth of averaged data for making any type of predictions... and determining the probability of hitting any particular wire on a power line is still a subject of much debate.



Apr 22, 2015 09:17:55 AM, rstealey at hotmail.com wrote:

Good explanation to add to what Tom wrote. Thanks.
The question still remains, however, Can this corona popping damage the receiver?
And you provoke and even more serious question now, Is the tower/antenna more likely to be hit by lightning because of the aluminum yagi with the corona.

As an aside, there is a wouff hong perched on the tip of the mast, in an attempt to ward off lightning as well as QRM. It has worked well for 17 years, at least the lightning part.
(Just kidding)

And I'm sorry, hotmail won't let me delete the attached text.

Rick. K2XT