Topic: Need some advice installing first guyed mast pole.

[gman19]

So, after 11 months in our new house I am ready to move my anemometer up to the roof.
I am mounting to the rear of the roof (not at the peak) so I am using a slope mount type tripod.  I am using this mast:

https://www.antennasdirect.com/store/Heavy-Duty-Telescopic-Mast.html

to extend the VP2 anemometer to the 33' level.  The transmitter will be mounted down lower close to roof level.

I have the cable, turnbuckles and all the screw eyes, etc. and will be doing this next week hopefully.  The last section of mast will extend about 4.5' above the guy ring.  I think I have a pretty good game plan, but are there any pitfalls that anyone with some experience in this area might can weigh in with?

My main concern is how "tight" the turnbuckles should be.  In my mind I am thinking they should be minimally "snug" such as to prevent excess sway, and not such that the mast simply cannot move at all.

Once my station is finalized, I can update my profile pic, that was at our old house, and I've simply been too busy until now to get back onto here and get back into Wx again.  It feels good to be back!

Thanks all!

[C5250]

Note that 33'/10 meters is above flat ground with no obstructions within 500' The full spec can be found here.

You do want the guy wire to be tight as loose strength if they are too tight. I would call it snug, remove any sag, yet if you push down on a guy the mast will move. And, yes, the mast will around a bit in higher winds, if no more than 6" dia @ 20' above the highest solid mount, its nothing to worry about.

In reality, the wind loading of an anemometer is so low that the mast itself is most of the wind load.

Oh, and don't forget to properly ground that mast.

[gman19]

Thanks C5250,
That's what I wanted to confirm.  I cannot meet the 500' no obstruction spec, at least to the north as there be some hardwoods galore.  Other directions are pretty much obstruction free.  I do plan on having my electrician advise me on how best to ground this thing too and meet best safety and codes.

I'll be sure and post photos once completed

Thanks again!

[C5250]

I cannot meet the 500' no obstruction spec, at least to the north as there be some hardwoods galore.

Same problem here. I guess we all can't live at an airport or on a farm. So we try the best we can.

I do plan on having my electrician advise me on how best to ground this thing too and meet best safety and codes.

If in the US, current NEC requires at least a #10 (#6 is better) ground wire to an 8' fully buried ground rod. That should also be connected to the structures primary electrical ground with at least a #10 (#6 is better) ground wire. Try to avoid sharp bends in the ground wire.

[gman19]

Yeah, I'm here in the U.S. (North Carolina).  I've read on some forums it is debatable whether it is proper to have 2 ground probes at one residence.  I don't see a problem with it, but the jist was that a strike could "jump" from one ground to the other.   I was discussing this topic at work with some other engineers and, as you indicated, we came up with grounding the mast to its own rod, then bonding that to the main house ground with a beefy #6 conductor.

The electricians are always nearby (new construction going on), so I will consult next chance I get and see what they suggest.

[ValentineWeather]

How would the mast be mounted?

I found this on lightning protection.  "No protection is needed for a television antenna or flagpole whose mast enters the earth. Both are automatically grounded, and lightning will simply travel down their length into the soil. But an antenna or other pole that does not contact the earth has to be linked to it by means of grounding equipment."

[LFWX]

Here are a few photos of how I attached my guy wires to the roof (my mast also has a few antennas, so this may be overkill for you)...
https://www.flickr.com/photos/30112397@N06/2869723088/in/album-72157607366155684/
https://www.flickr.com/photos/30112397@N06/2868894931/in/album-72157607366155684/

...my first method did not work so well during a wind storm (one attachment point pulled loose, fortunately when it hit the roof the antenna boom hit the roof square and nothing, except the bulked mast, was damaged)
https://www.flickr.com/photos/30112397@N06/2879381224/in/album-72157607366155684/

...original and current hardware
https://www.flickr.com/photos/30112397@N06/2879378866/in/album-72157607366155684/


Current antenna arrangement (antenna is lower and guys wires spread out further)
https://www.flickr.com/photos/30112397@N06/2879380174/in/album-72157607366155684/


The anemometer wasn't the only casualty (the tree missed the house and only broke a few boards on the fence), look closely at the roof to see how the antenna saved everything.
https://www.flickr.com/photos/30112397@N06/2865781132/in/photostream/

[kcidwx]

I seem to have the opposite opinion of most when it comes to installing anemometers. My thought process is how can I make this  installation withstand 60+ mph winds. Because that's when I'll really want the wind data. A couple years ago we had such an event happen were I was getting winds over 60 mph for 30-40 seconds. Trees were down everywhere, shingles ripped off houses but there was my anemometer still standing tall. I got some great wind data. I think I was the only one walking around with a smile on my face even though I had a huge mess to clean up. I even got a knock on the door from an insurance agent walking the neighborhood surveying the damage asking if I had any good wind data from the storm. 

Being you are in North Carolina with the risk of tropical storms you may want to give some thought to really anchoring it down just in case.

[C5250]

Yeah, I'm here in the U.S. (North Carolina).  I've read on some forums it is debatable whether it is proper to have 2 ground probes at one residence.  I don't see a problem with it, but the jist was that a strike could "jump" from one ground to the other.   I was discussing this topic at work with some other engineers and, as you indicated, we came up with grounding the mast to its own rod, then bonding that to the main house ground with a beefy #6 conductor.

The electricians are always nearby (new construction going on), so I will consult next chance I get and see what they suggest.

Likely pretty much the same thing with addition of exothermic welding of the ground wire to the rod(s). Which reminds me that any buried connectors must be rated for burial.

As for what you have read about 2 ground probes, I can think of two situations that might relate. The first would be independent unconnected grounds, never a good idea as the two will always have a different ground potential and therefor anything connected between the two will have a voltage difference and current will flow between them.

The second is more recent and related to the current NEC requirement for two grounds (usually rods) in certain cases. Years ago when virtually every building had its water supplied through a buried metal pipe, the water supply pipe made an excellent ground. Concerns that that may be inadvertently disconnected led to the requirement of a secondary ground (usually a rod). More recently, the growing use of plastic water supply pipe made the use of that useless as a ground and hence the current requirement for two grounds.
 

[gman19]

Thanks all for the replies...
Valentine, the mast will be roof mounted, 100%, so I'll have to ground the mast.

Great idea LFWX using the 4x4's between the rafters...I might have to resort to this too if I can't find sufficient anchor points directly into my rafters.  I'm hoping to be able to hit rafters with all anchor points, we'll see.
My wind loading will be minimal with the Davis being the only sensor up there....for now anyway.

I'm going to pick up some ground wire tomorrow. 

I barely got started on this project this afternoon, and as my luck goes, thunderstorms moved in right as I drilled my first pilot hole...the project will continue in the morning.  At least the roof will be cooler! 

I'll also do more inquiry with some local electricians regarding grounding...