In article ,
Alex Coleman wrote:
I have got a thermometer with a remore temperature sensor that sends
radio signals to update the base unit's display. The base unit also
has its own temperature sensor to let it display the indoors
temperature as well as the sensor's temperature.

The sender unit's antenna is a coil of wire which is about 1/4-inch
diameter and a couple of inches long. See these pics:

If the sender unit has a FCC ID number on it, you can go to
http://www.fcc.gov and put that into a search form webpage and
get the frequency that it operates on.

TWO QUESTIONS: What is the best orientation for each of these units
so their antennas are postioned optimally? For simplicity I am
assuming no obstructions.

TWO MORE QUESTIONS: which component in the sender is the temperature
sensor? The sender's case seems sealed with no air vent!

Similarly, which component in the base unit is the sensor for the
indoors temperature? You can see the air vents in the base unit in
one picture linked above but which component is the temp sensor?

They're low enough power that they don't generate much internal
heat. So the sensor is just another part on the circuit board. On a
cost basis , probably a thermistor, (a temperature sensitive resistor),
that would just be an epoxy coated (or glass) blob with a couple of
leads on it. They could also use a diode, or a temperature sensor IC
(that looks like a transistor).

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)