[wxqc] Grounding of anenometer mast

[Gerry Creager N5JXS]

Dennis,

I've a couple of thoughts.

1.  I'd strongly recommend grounding the mast as you're presenting a 
nice target for stray lightning.

2.  Almost certainly, the TV antenna is mechanically bonded to the mast. 
  Very few of the antennas are isolated and antennas design tends to 
require a ground-poise to make the antenna work.  A floating antenna 
without a ground reference is a poor performer.

3.  Using the shield of the coax as the sole lightning ground return is 
a bad idea from a lightning protection standpoint as it's not a real 
low-impedence return for that much energy and your TV or more exotic 
home entertainment hardware will almost certainly suffer some damage. 
If you're in a real lightning prone area, I'd be looking at 
gas-discharge tube lightning arresters (Poly-Phaser is sort of the index 
brand) to protect expensive hardware.  It's what I use in ham radio and 
wireless installations.  They also make a version for ethernet that 
could be used to pass the data from the wired VP hardware.

Lightning is an interesting issue to have to deal with.  Having lost a 
fair bit of ham gear some years back to a poorly prepared mast, I'm a 
bit more sensitive to how to prepare now.

gerry

Dennis Maier wrote:
> As soon as it's safe to climb up on my second story garage roof I intend to
> extend the height of my anemometer from about 7' to maybe 15' or more above
> the roof.
> 
> At the present time the Davis Vantage Pro anemometer is connected to their
> Wireless Anemometer Transmitter mounted on the mast just above the tripod.
> Also mounted on the same mast a couple feet below the anemometer is a large
> TV antenna used to pickup On-Air HDTV. The TV antenna coax is routed into
> the garage through the roof eaves vent down to the ground floor and into a
> metal patch panel enclosure and grounding block then into the house. The
> enclosure and a coax grounding block are grounded with #4 copper wire
> through the wall outside to a ground rod. I did it this way to preserve the
> appearance (no unsightly wires) of the newly vinyl sided house and garage.
> At this time the mast is not grounded.
> 
> Was this, routing the wires inside the building before the ground block, an
> unsafe decision from a lightning standpoint?
> 
> Because of occasional missed data packets from the Wireless Anemometer
> Transmitter when I extend the mast I will probably hardwire the anemometer
> to the Davis ISS and do away with the Wireless Transmitter. So that will be
> additional wires running from the mast to inside the home.
> 
> I live on the waters edge of Saginaw Bay off Lake Huron in the Thumb of
> Michigan. A few years ago lightning struck the electrical wires entering my
> home at the utility pole, so I know it likes my area.
> 
> What are forum members thoughts about grounding the mast? I worry that
> grounding the mast will just attract more lightning strikes.
> 
> 
> Dennis Maier
> CW4869
> 
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-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University	
Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.862.3983
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