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Re: Topband: BOG antenna

To: <topband@contesting.com>
Subject: Re: Topband: BOG antenna
From: "Tom W8JI" <w8ji@w8ji.com>
Reply-to: Tom W8JI <w8ji@w8ji.com>
Date: Sat, 15 Jun 2013 13:45:05 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
It's refreshing to get input from many sources. I always believed that the static was not from a nearby tower as I have three close by. The BOG antenna did not hear the noise, but other antennas did.

A nearby tower is just one source, Bruce.

In broadcasting it is known dry, high speed blowing snow can cause dangerous voltages on an antenna. The first key word is dry, second key work is speed.

That probably doesn't mean much, because towers and well insulated antennas charge just from a modest dry breeze. If someone walks back by the creek and touches the insulated tower there, even on a clear day, there is a good chance they will get knocked pretty hard.

Think Guy K2AV has it close but I can not help but think that rain drops, and snow flakes, due to their speed, carry the charge. But as in the case of lightening the direction can be argued. Guess something on ground has a sharper point than a thunder cloud. Then there are cloud to cloud strikes. Hmmm. The sharpest cloud ? whoa !

I think the real tests are:

1.) It is very well established that the highest and most pointed antennas or structures have the most p-static by far. Usually any lower antennas, even those struck from a side angle by the same precipitation, are usually dead quiet or very low noise. If the charge was carried by particles, it would be the same or similar on all. It isn't. The difference in noise of antennas indicates it isn't normally particle charge.

2.) Even without moisture or particles, inclement weather or even dry winds bring p-static. No particles, yet the static occurs. This indicates corona to the air.

3.) P-static normally vanishes immediately following a strike, and then builds rapidly. This indicates the noise is corona to the air.

4.) Many people have bare antennas some small or modest distance above earth, and never have p-static issues. If it was precipitation or particle borne charges, nearly everyone would have identical results with bare conductors. The odd-men out would be those with quiet, bare, antennas of almost any type.

5.) The effect is very clearly height driven, and keyed to something being the tallest, sharpest (protrusion), object. This is why quads, which are "boxy", have the reputation of being "low noise". As a matter of fact, the quad was popularized by use at HCJB to eliminate corona.

There are often isolated circumstances without clear understanding that seem to point in one direction, so I tend to go with something that fits what almost always is observed. The overwhelming evidence points to charge gradient between the sky or atmosphere and earth, and not little charged particles hitting out antennas and making a tiny spark. Even the noise pitch is almost always unrelated to quantity of particles.

73 Tom
All good topband ops know how to put up a beverage at night.
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