VP2 Upgrade Adventure

I need to think through the installation of my new VP2 (Thanks again Brian) :smiley:

I’m replacing an OS WMR928 which has the T/H and rain gauge as separate sensors, and the VP2 has all the sensors in one stack. So where I was able to put the 928’s T/H sensor in a shady place and the rain gauge in a rainy place I now have to find a location that suits all the sensors at once which may be tricky. Here’s the problem (without pictures I’m afraid)…

The front garden is out. Too public and the chief garden designer wouldn’t allow me to put it there even if I wanted to risk it! The back garden is well below the level of the house (the peak of the roof is about 35 feet above the garden), so the house casts quite a rain shadow over the garden. The prevailing wind (and rain) comes from the west and the house is due west of the garden #-o The garden also has a lot of mature trees/bushes on all sides, so the only place to put the rain gauge without run-off from vegetation would be in the middle of the lawn. With two boys (7 & 9 yo) in the house this isn’t a viable position! So I don’t think that ground mounting (well on a post in the ground) is an option.

My current rain gauge is mounted on the edge of the (flat) kitchen roof. It gets a reasonable view to the west but it’s rather too high (16ft above ground level) and therefore likely to be impacted by wind blowing rain over it. Not much I can do about that though.

So this sort of fixes where I can put the ISS. However, this means that I have to put the T/H sensor in the same place. I don’t think this is ideal though. There are lots of white painted walls which will reflect radiation in the sun and I suspect there will be a fair amount of reflected heat from the kitchen roof (it’s metallised felt) in the summer. There’s also the exhaust from the central heating system about 6 feet away (horizontally). Finally there is also a place nearby where a thin layer of water gathers on the flat roof after rain (the roofers clearly didn’t get the drainage slope quite right) and this could affect humidity readings. I’m worried that all of these may affect the T/H readings. I’ve added an optional daytime FARS to Santa’s delivery and this will help, but will it be enough to counteract the adverse conditions? Can anyone think of any other options open to me?

One other thought…the main difference between the daytime FARS and the 24 hours FARS appears to be a rechargeable battery. I don’t know why there isn’t an option to add a 24 hours FARS, but there isn’t so I couldn’t get one. However, is it possible to modify the daytime FARS to add a battery and therefore turn it into a 24 hour unit? It doesn’t sound like a huge mod and it should be possible using the standard connectors, i.e. not cutting any wires. Has anyone done this, or is there some reason why it wouldn’t work?

How about a on a tripod on that flat roof?

Is the solar panel bigger on the FARS with battery? If so I would question that capability of the standard panel to both run the fan and charge the battery.

Mounting isn’t too much of a problem. I think I can mount the ISS on a pole on the house wall or the small wall that runs tound round part of the edge of the flat roof. The heating and humidity effect of the roof environment is the real concern. Maybe I’m overreacting…if the FARS is designed to cope with the ISS exposed in full direct sunlight, then maybe any extra radiation from the walls/roof isn’t going to affect things very much?

The standard ISS appears to have one solar panel on the SIM (?) cover (I’ve not picked up all the new terminology yet!). There’s a replacement SIM cover with the FARS unit which has two solar panels on it. It’s difficult to tell from the small pictures I can find of the VP2 with 24-hour FARS, but that appears to have a single solar panel on the SIM cover and an additional solar panel alongside the radiation shield. The extra panel looks like it might be bigger than the one on the SIM cover, so maybe that’s the difference…a bigger panel is needed to charge the battery and run the fan simultaneously. If that’s true, then I would have thought it might be possible for someone to come up with an addon with a suitable solar panel plus battery that uses the same plugs/sockets as the FARS addon to turn it into a 24-hour model. I’d have thought that a suitable solar panel plus battery would only cost

Yeah, I’ve got at least two excellent spots for an additional VP2.

Unless global warming has really toasted you already I think you’ll be OK with the amount of solar radiation it’ll get, I mean these things do pretty well in Arizona :slight_smile:

I’ll cruise the Davis site a bit later, I’m not very up to speed with the VP2 options (trying to stay untempted, but now I’m thinking I might just slip one into the house painting bill :wink: )

Glad to hear that you have upgraded to the VP2, Chris! :slight_smile:

It’s pretty difficult to really say what you could do without any pictures…but the tripod idea that niko mentioned sounds like a good idea. How far is the flat roof away from the house?

–Tim

Pictures are tricky…it’s dark when I go to work and dark when I get home. Maybe I’ll manage to grab some at the weekend.

The flat roof is attached to the house. It extends about 7ft south and about the same east, so the corner is about as clear a spot as I’ve got.

Chris, you lucky BLEEP getting a VP2 :lol:

Just taking all the bits out of the box and reading the manual (yes actually reading it) to see how they all fit together!

To tell you the truth, I’m really curious to see how well the drip ring on the anemometer works out…

We’re expecting a significant amount of sleet/ice here (possibly up to 0.25" of it 8O) and it’s supposed to be breezy.

–Tim

if you live on or near hill tops/ridges, then your overnight temperatures can be alot higher than people in the same area who live in hollows/basins/flat areas …

I’m making progress…

Console setup and data logger installed.
Anemometer set up and connected to transmitter
Rain gauge set up for 0.2mm.tip (what is the 0.1mm/tip setting for on the console?)
FARS built and connected to ISS.

That’s enough for tonight. I need to get the serial to USB adapter next so that I can hook the console up to the PC and get WL installed. Then it’s outside when I can get a man with a ladder to climb up high and bring my anemometer mast down to ground level.

Sounds good. I have a new toy waiting to be set up too - a new PC is sat on the floor at the moment - I am waiting on a serial to USB converter too so I hope my lowly WMR928N works ok with that or I will have to get a serial port PCI card!!! I am away at the weekend so the new PC will have to wait until Monday to be powered up. So my weather data may disappear for a while.

One day I will get a Davis!

Is it normal for the outdoor T/H sensor to give different readings to the indoor sensors (when they’re in the same place)? I’ve got the console sat on top of the rain gauge, so the sensors are very close. The console is currently showing 19degC for outdoor and 22degC for indoor (my OS T/H sensor about 4 feet away is saying 21degC. Humidity is also different (53% outdoor and 45% indoor), but this might just be down to the temp difference. The console and ISS have been together in the same room for 24 hours, so they should have reached a stable and similar temp.

I’ll monitor it for a while longer, but is this to be expected?

is the light on, on the console?
also the rain gauge is black…try moving it away from that
also i dont think the specs on the indoor temperature as as accurate as the outdoor temperature…so differences will occur…

I just went through this with mine. I had a weather monitor II that was zapped with a serge from the computer and bought the VP2.

I did as you have done and put them in the same room for a long time. I would say that they should read the same if they are in the same room for a reasonable length of time. There is a way of adjusting that. If you look in your manual to see the procedure. The only thing that is the unknown is which temperature is the correct one so that you can adjust the right one.

I got another thermometer to put in the same place and decided which one was correct. Unless you have a hygrometer, it is a tossup about the humidity. I adjusted mine assuming that the indoor one was correct and may need to refine that based on humidity readings in my area.

This was my experience and method for doing this.

Gary

I think this may have been true before but acc to the vp2 manual on the website they are both +/- 0.5 deg C. I’m not surprised by the discrepancy Chris is seeing though, there are so many possibilities for air currents or other effects acting differently on the two sensors. If it was all wrapped in a thermal insulating blanket for a while then I would expect them to the same within the limits of the spec.

I have my VP2 set up on the roof using a TV aerial stand - the bottom of the unit is a touch over 2 metres higher then the peak of the roof.
When I set it up, I had three different weather stations all located in a close proximity with all of them showing very similar data so didn’t need to tweek anything.
Old Chinese Proverb - “Man with one watch always know time, man with two watch never know time”

Temperature radiation from the roof was my biggest concern on installing there, but I also had issues with location in the garden area - too many trees and shrubs - so up there it went. Temperatuers readings seem to closely mirror other data in the general area, so I am quite happy with the readings I get . In New Zealand of course it is unusual to have no wind at all to flow over the sensors so roof radiation is not usually an issue. Obviously, up there grass temperatures get missed.


VP2Setup.JPG

Is that a “hot tin roof” ?

[quote author=nikoshepherd