[wxqc] Grounding of anenometer mast

[Keith Miller]

> -----Original Message-----
> From: wxqc-bounces at lists.gladstonefamily.net
> [mailto:wxqc-bounces at lists.gladstonefamily.net]On Behalf Of
> Ken.A.Brown at noaa.gov
> Sent: Tuesday, March 14, 2006 7:25 PM
> To: Discussion of weather data quality issues
> Subject: Re: [wxqc] Grounding of anenometer mast
> 
> 
> When we connect them with coax we use a 300 ohm to 75
> ohm balun transformer.  I just checked a couple of baluns
> and there is no DC path between the 300 ohm section and
> the 75 ohm section.

Until the first lighting strike. :) You can be sure the
insulation resistance in a balun is minimal.

Interesting thing I noticed. Many years ago I installed a
21' antenna atop a 20' mast, which was well grounded and I
had gas discharge suppresors to another ground where the
coax entered the house.

Lighting and blown equipment was never a problem all the
years that was up.

A few years ago that was taken down and since then I've had
at least 2 or 3 instances where a close lighting strike had
me jumping because of a "snap" noise from the AL window
frames. Had some issues with a couple electronics bits
after one of them too.

Grounding a mast is highly recommended, it's not so much
because that'll help redirect a lighting strike, nothing
will save your equipment from a direct strike. Or worse a
fire that might start from one. But because grounding drains
the static buildup that will attract a direct strike.

In addition to grounding the mast, any cables from the mast,
in order to meet NEC, entering the building should also have
a ground method at the point where they enter the building.
The NEC requires that that be at the entry point.

If that's lacking, your insurance may not cover a loss. Just
something else to think about.


Keith
--
CW5250