BT Range (re-post from Totally Off Topic)

Reposting to Beginners, originally in Totally Off Topic.

I have a dozen tags around my house. My iPhone sees some of them most of the time, and some are really hard to connect to.

First of all, I find some of the tag use examples on a little optimistic. I put one tag in my car, to see when it is warm enough. The garage, a wooden shed 50 m from the house, was not reachable from a window with line of sight to the garage. I put another tag on the porch, 5 m from the kitchen window. It connects, occasionally. I wonder if cold weather makes a difference for the tag on the porch. Now it is -5…+5 degrees, and the tag has the standard battery. A third tag, in my wine cellar in the basement, also connects only occasionally, but that I can understand, with reinforced concrete structures.

Any ideas, does cold weather affect the battery and then the output power? Or is there a good transmit orientation for the tag, e.g., perpendicular to its face?

Cold weather affects the battery, but there’s an internal DC/DC voltage regulator which keeps the voltage going to radio stable in all conditions.

Radio is strongest “upwards”, the effect is a few decibels if I recall correctly. Sometimes it’s enough to make a difference. The effect of surface tag is installed on has a bigger effect, I think a RuuviTag on metal had -10 dB output power compared to RuuviTag on wood or glass.

Thanks. The tag is attached to a 2x4 board. So, on wood, not on metal. And there should not even be any metal, just some wood and an old-fashioned non-metallic window, between my phone and the tag. The stability of radio independent of the battery voltage, makes sense.

About directions, is upwards the same as perpendicular to the face of the tag?

Yes, on the side with components on PCB/Gore-sticker on enclosure. Not to the side with test points. Like in images below, strongest direction is facing you.

This is the way I have attached the tag, facing the house. Maybe I need to try with another tag, to see if the unit now on the porch is somehow defective.