Author Topic: Newbie questions  (Read 1538 times)

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Offline jhoke

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Newbie questions
« on: July 20, 2014, 12:20:54 PM »
So, I've bit the bullet after about a year or so going back and forth - Ryan from Scaled Instruments helped me a LOT with my decision.

My Davis 6152, logger and Anemometer Transmitter Kit looks like it will arrive tomorrow to feed my geekish needs but I have some questions about siting the anemometer. Reading through the forums, I seem to be in a similar tradeoff that other's have found themselves in, and looking for suggestions

Location is in the Pocono Mountains in a fairly wooded area

Looking at mounting the anemometer separate from the rest of the unit. The ISS/Temp/Rain/etc will be mounted on a 4x4 that I will be putting about 6' off the ground on my back lawn near the septic mound/leach field - abt 20-30' from the house and 20' from the tree line behind it, and 30-40' from trees on one side ... 100' from the tree line on the other... best place I can put it so that its out of the way enough to prevent wifeagro for it being in the middle of the yard

for the anemometer - my choices are
1) Chimney Mount:
I have a wood burning fireplace, it is only used in the winter once or twice a week (not for home heating, but for hanging out by the fire). The chimney is on one side of the house and the ground is on the other - so I assume if I go with an antenna mount, put the wind sensor abt 10' above the chimney (~45' off ground) and away from most trees, that I will need to ground the pole/unit and talk to a local electrician to find out if I need to connect to the ground on the other side of the house or just bury the copper rod 8' down

2) I have an eave over an attic window that overlooks the garage roof. I could mount a crossbar and put the wind sensor 10' above the roof that way - which is near the house electrical ground

3) mount it on a tripod in the rear of the home, near where I am placing the rest of the unit - this would not be able to go above the tree line (and could bring negative wife acceptance factor  :shock:

The home faces just south of due east - so the chimney and eaves mounts will have sun nearly all day (noon is right over the roof the majority of the year).


The chimney mount will be the least 'impact' to the home (ground wire dependent) while the eaves mount will be the easiest to reach for maintenance (climb out window onto roof).

Bing shows a fairly good image of the house - more trees have been taken down since Sandy, but otherwise good view.
http://binged.it/1wMRTUZ
 
You can see the chimney on the left, and the main roof's peak/eave on the right

I have a tendency to overthink things - so I'm hoping that someone can provide their opinion and why either of the two spots are better (or a toss up)

Thanks in advance! been finding a LOT of great info here :)

Offline miraculon

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Re: Newbie questions
« Reply #1 on: July 20, 2014, 12:52:44 PM »
Quote
1) Chimney Mount:
I have a wood burning fireplace, it is only used in the winter once or twice a week (not for home heating, but for hanging out by the fire). The chimney is on one side of the house and the ground is on the other - so I assume if I go with an antenna mount, put the wind sensor abt 10' above the chimney (~45' off ground) and away from most trees, that I will need to ground the pole/unit and talk to a local electrician to find out if I need to connect to the ground on the other side of the house or just bury the copper rod 8' down

2) I have an eave over an attic window that overlooks the garage roof. I could mount a crossbar and put the wind sensor 10' above the roof that way - which is near the house electrical ground

3) mount it on a tripod in the rear of the home, near where I am placing the rest of the unit - this would not be able to go above the tree line (and could bring negative wife acceptance factor  :shock:

#1 sounds OK, but I would be concerned about corrosive gasses affecting the anemometer and its transmitter over the long haul. You will want to locate the transmitter where you can access the door to change the battery eventually. Where were you planning on installing the transmitter? Same mast as the anemometer wind set, down lower?

I know that a lot of people here on the WxForum have used chimney mounts, maybe someone will chime in with their experiences pro or con. Maybe it will be OK.

#2.
Quote
which is near the house electrical ground
Were you considering grounding the mast to your house ground? You might want to reconsider this. The last thing you want is to attract a lightning strike and route it into your house ground wiring.

#3, the trees will affect the wind speed so this might be a distant 3rd choice. Plus, the Wife Acceptance Factor is important.

Greg H.




Blitzortung Stations #706 and #1682
CoCoRaHS: MI-PI-1
CWOP: CW4114 and KE8DAF-13
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Offline jhoke

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Re: Newbie questions
« Reply #2 on: July 20, 2014, 01:07:58 PM »

#1 sounds OK, but I would be concerned about corrosive gasses affecting the anemometer and its transmitter over the long haul. You will want to locate the transmitter where you can access the door to change the battery eventually. Where were you planning on installing the transmitter? Same mast as the anemometer wind set, down lower?

I know that a lot of people here on the WxForum have used chimney mounts, maybe someone will chime in with their experiences pro or con. Maybe it will be OK.

Re Chimney mount - hopefully others chime in... this is the most optimal spot from a siting perspective, but I am worried about the gasses from the chimney ... another option is to mount from the chimney on a 5' offset... need to think about that...

Re Transmitter: Exactly - was going to place the transmitter about 10' off the ground for the chimney mount, or right next to the window for the eaves mount

Were you considering grounding the mast to your house ground? You might want to reconsider this. The last thing you want is to attract a lightning strike and route it into your house ground wiring.


I've seen conflicting information on this - and I am not an electrician (i just play one around the house) so was going to get the final call from an electrician I trust. As this is completely wireless (to the house at least) I think that sinking a grounding rod into the soil should be sufficient - but will check with the pro and get it done right (and code)


Thx again!

Offline dalecoy

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Re: Newbie questions
« Reply #3 on: July 20, 2014, 01:42:39 PM »
Just for a moment, forget about grounding.

The anemometer kit will measure the wind where it's located.  Well above the chimney would be OK.  Or consider a tripod mount above the center of the roof?

Now, about lightning... don't get overly concerned.  You can't "attract" lightning - and it's just as likely to hit one of those trees, or the chimney, or the roof of your house, as it is your anemometer.  Arguably, connecting a ground wire to the anemometer mast might (slightly) increase the chances of it being hit.  Feel free to consult your electrician, of course, and follow that advice - at least you'll feel better about it.

Offline ValentineWeather

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Re: Newbie questions
« Reply #4 on: July 20, 2014, 03:26:15 PM »
I would probably go with tripod mount on roof peak for easiest access. If wireless I wouldn't ground it at all, I'm no electrician but understand this is for satellite, radio or antenna feeds entering the house. The grounding helps prevent static charge build up or divert static build up from nearby lightning strike helping prevent charge from damaging electronics in home. Any direct hit that little ground rod won't do much to prevent damage. 
Randy

Offline jhoke

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Re: Newbie questions
« Reply #5 on: July 21, 2014, 06:02:17 PM »
Thanks all

I will be going with the chimney mount  (roof mount was shot down due to low WAF) in the mean time, while I know it won't be perfectly accurate, for testing and getting data from the unit to test some programming I'll just mount the anemometer to the pole I am placing for the ISS... 10' over ground is better than nothing

testing comms now... all in working order

now to see what I can do with inbound data and a bit of ruby magic

Offline nincehelser

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Re: Newbie questions
« Reply #6 on: July 21, 2014, 06:29:10 PM »
Any direct hit that little ground rod won't do much to prevent damage.

I beg to differ.  A "little ground rod" is incredibly effective at diverting lightning safely. 

I've had the house struck without and with proper grounding.  I can assure you that a "little ground rod" works wonders in preventing your structure from bursting into flames.

Offline Josiah

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Re: Newbie questions
« Reply #7 on: July 21, 2014, 07:07:47 PM »
Any direct hit that little ground rod won't do much to prevent damage.

I beg to differ.  A "little ground rod" is incredibly effective at diverting lightning safely. 

I've had the house struck without and with proper grounding.  I can assure you that a "little ground rod" works wonders in preventing your structure from bursting into flames.

Whatever Lightning hits is toast, plain and simple.
Since Lightning is a result of Static electricity buildup, the Idea behind any grounded Lightning protection system is to prevent static from building up in the air by dissipating it to ground.

I'm Speaking from personal experience, we used to get a lot of ground strikes (in the middle of fields no less) every time a thunderstorm rolled through. We've had significant portions of our electric fences and several trees blown apart by lightning. We've even had it hit are transformer putting us without power for a couple of days. That was until we started putting up grounded 33' Vertical antennas (we're Amateur Radio operators). That was about 4 years ago and since then we have had plenty of thunderstorms roll through but have not seen a single ground strike. Come to think of it we really haven't seen much Cloud-to-Cloud strikes either.

So IMHO its not necessarily just a matter of how good of a ground you've got, but more a matter of how well the Static can be dissipated out of the air.

Offline jhoke

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Re: Newbie questions
« Reply #8 on: July 21, 2014, 08:41:10 PM »
Well, for grounding, i'll follow whatever codes my municipality forces upon me ...

As for the station - its all set up collecting data waiting for tomorrow after work to be mounted... i figured I'd collect some throw away data tonight...

The ISS is sitting on top of a white cooler on my deck - crap for accuracy - but fine for testing the communications, getting the weather link usb setup done, and testing out some MAC software .... then mount it all on a 10' 4x4 tomorrow until i get an antenna rig to put on the chimney ... after my ankle is out of this stupid soft cast... ladder + bad ankle = bad things waiting to happen :)


Offline nincehelser

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Re: Newbie questions
« Reply #9 on: July 21, 2014, 08:50:35 PM »

Whatever Lightning hits is toast, plain and simple.
Since Lightning is a result of Static electricity buildup, the Idea behind any grounded Lightning protection system is to prevent static from building up in the air by dissipating it to ground.


Sorry, but no, that's not the idea.  The idea is to divert the inevitable lightning strike current to ground so that the damage is minimal if non-existent.

Quote

I'm Speaking from personal experience, we used to get a lot of ground strikes (in the middle of fields no less) every time a thunderstorm rolled through. We've had significant portions of our electric fences and several trees blown apart by lightning.

I'm an electrical engineering who has dealt with lightning and lightning protection issues, both on a personal and professional basis.

But yes, I can believe you about electrical fences and tress.  That's because they themselves don't provide a very good path to ground.

Quote
So IMHO its not necessarily just a matter of how good of a ground you've got, but more a matter of how well the Static can be dissipated out of the air.

Sorry. When lightning strikes, a proper grounding path diverts the current with minimal, and often zero, damage.  Trying to dissipate charges to avoid lightening is a fool's game.  You just can't do it.   Mother Nature will always win.  She's too big and powerful.

Power = current squared times resistance.  You can't do much about the lightning's current, but you can make the resistance as close to zero as you can.  If you make the resistance close to zero, the power dissipated also heads towards zero.

If you do not provide a good path to ground, then the lighting will follow an alternative, more resistive path (and probably an inconvenient one).  Plug more resistance into the power equation and you'll understand why things start exploding and bursting into flame.
« Last Edit: July 21, 2014, 08:56:32 PM by nincehelser »

Offline jhoke

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Re: Newbie questions
« Reply #10 on: July 22, 2014, 05:35:14 PM »
well -- i'm up and running with a few short term compromises :)

Put up a temporary 10' 4x4 with the ISS at 5.5' above ground, and the wind sensor at the very top... far from perfect on that note, but i'm not getting up on a ladder to the chimney for a month or two...

Weatherlink USB to my Mac - working... WeatherCat up and running ... sending data to Wunderground and my website ... still using basic/simple auto generated html... sooner or later I will push data to my website's mysql DB and have some fun with ruby and/or php

http://hoke.org/weathercat/
http://www.wunderground.com/personal-weather-station/dashboard?ID=KPAALBRI11

Thank you to all who helped me in this thread with info :)

 

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