Hi Brian,adam5 wrote:Hey Ray,
Just took a look at the pictures of your temp/sensor placement. I guess I didn't realize just how close it is to that dark fencing. I would speculate that a day of good sunshine on that fence might just add a few degrees to your temps. If it were me, I would seriously consider getting your sensor farther out into the yard...if that is even an option for you. Some folks simply do not like the idea of sinking a post in a more open part of their yard.
I thought long and hard before choosing that spot. I chose it because that point is furthest from the house and gets the most sun. If I brought it closer to the house it would be close to the stone patio and although it would be well away from any fencing the patio would have a worse effect I think. Another compromise might be to move it towards me on that right hand border so it's away from the corner but that right-hand fence gets the sun all afternoon whereas the taller one doesn't get any in the afternoon (on my side) when the highest temperatures occur.
That was my main concern. That the air immediately around the ISS would be warmed by the enclosed space so using a fan would make no difference at all. Unfortunately I have a small garden which is 80% lawn surrounded on 3 sides by fencing. But if I move it towards the camera position along that right-hand border I think that would make it more open and even though that fence gets the sun all afternoon it's not as high and any warmed air might not extend to the sensor. How far from a fence do you think it needs to be?As far as the daytime fan is concerned, given your current setup...a tough call. On one hand a fan will certainly keep the sensor aspirated and remove any build up of "heat" inside the shield, particularly on calm wind days. On the other hand a fan will pull in more air from around the sensor which could potentially be warmer due to that fence
It's proving extremely difficult Brian as you can see. I will take some photos over the weekend and they may give you a better idea of my garden layout. I also placed it there as it has line of sight to the console aerial but the anemometer transmitter on the front of the house sends a signal through a brick wall and an internal one without problem so I can probably move it elsewhere without compromising the signal. I just don't want it in the lawn because it would be liable to being knocked as well as being a pain to mow around.In the end all you can do is strike the best balance between your space limitations, sensor exposure, and minimizing sources of artificial heating. Not always an easy task as you can see.
-Brian
I have a Oregon Scientific thermometer sensor which I can place in various parts of the garden and come the spring I will use that to determine which places might be better. It's all about compromises in urban areas as you say.