I've had this Davis VP2 station up for about a year, but haven't been able to post these pics until now.
I wanted to get the anemometer up near 33 feet, so I used the basic design for a tilt-over mast found at these sites: Tilt-Over Mast
and WV7U Tilt-Over Antenna
… The main differences are that my mast support bracket needed to be non-permanent as I was planning to move to a new house at some point in the future and I added guy wire support to reduce high wind wobbling.
Here's the hole for the bracket foundation. It's 2' x 2' x 2' with some rebar.
This is the template used to hold four 18-inch j-bolts in the exact location while the cement was setting so the j-bolts would mate up with the bracket base plate holes.
The mast consists of square steel tubing. Lower section is 20' and upper section is 10', with a one-foot overlap. A round tube is welded at the top to accommodate the anemometer u-bolt mount, placing the instrument approx. 30ft high.
The bracket itself is two pieces of "L" beam steel, seven feet high, welded to 1/4" plate steel. The base plate sits on top of four large nuts screwed onto the j-bolts, allowing the mast to be leveled. Once leveled, nuts on the top side of the base plate secure the bracket in place (see diagram in post #6 below).
The mast pivots on a stainless steel bolt near the bottom. For ease of wind vain alignment, the bracket was installed so that the mast points due north when down.
Copper lightening rod welded to the mast. Of course a direct hit would take out the anemometer electronics and the ISS located 30 feet away, so a rod probably serves little, if any purpose. One thing I have noticed, it draws birds away from the anemometer as they prefer instead to sit on the higher lightening rod perch. For protection, anemometer cable runs inside mast.
Walking the mast up. I don't have the steel specs in front of me, but I tried to get the thinest I could to keep the weight down, but at 30 feet, the mast is just barely manageable by one person - it's pretty darn heavy (with two people helping, it's no problem). If needed, I could use a come-along winch to lower (it's harder to safely lower than to raise). ... (I posted a lighter, safer design a few posts down.)
Top bolt to lock the mast in place.
Project finished. Station is located at 7400ft. Mast is held solidly in place with the help of three guy wires at the 21-foot level. The top will wobble only slightly above 40mph.
4"x4" ISS post located 30ft from the mast for optimal sighting purposes. Top of post is cut at an angle to eliminate rain splash into the bucket. Radiation shield is 5ft above ground level. Bird spikes
protecting rain bucket is made from old metal fencing, held in place with a large hose clamp. The shelter behind the ISS houses an electrical connection for the rain bucket heater
and a daytime fan-aspirated radiation shield (DFARS) converted to 24hr/ac power (coming soon).
The cable connected to the Davis anemometer is 40ft long, so I needed an extension cable to get it to the ISS. I made one from outdoor-rated CAT5 twisted-pair and just as an experiment, instead of soldering the wires together, I left the RJ-11 connector intact and used an inline coupler to connect the two runs together.
The junction is sheltered inside an outdoor extension cord box. So far, there have been no problems with this connection, through one winter and summer. Exposed cable leading from the mast to the ISS is protected by plastic split-flex tubing (that was recently damaged
, possibly by a rat or squirrel).