N8UR Temperature Readings

I'm monitoring the temperature both outside our house, and in my basement workshop/lab, using a TempTrax E4 four-sensor thermometer system that outputs via ethernet (I previously used a TempTrax 2000, which is similar but has two sensors and talks RS-232). It has a stated accuracy of 0.5° F over normal outdoor temperatures, and a resolution of 0.1°. The temperature is logged every five minutes, and graphed every fifteen minutes here for your viewing pleasure. Details of the measurement setup continue below the pictures.

Measurement Technique

The data logging and graphing is done on a Linux computer system using a combination of homewritten software (available as "temptrax.tgz" from my download site) and a graphics package called Grace.

I've located the outdoor sensor in a radiation shield on the north side of our house, as isolated as I can reasonably make it from house thermal effects, dead air, and direct sunlight. By the way, I'm located in Dayton, Ohio, so you're seeing the temperature at about N39° 42', W84° 10'.

My main interest in measuring the basement temperature is to identify any sensitivity of my frequency standards and other gear to environmental changes, so I want a measurement that resembles what the heavy, rack-mounted, metal boxes see. The undamped sensor will swing several degrees up and down with every cycle of the furnace. The gear is massive enough that it doesn't react to those transient temperature swings.

The basement sensor has been a work in process as I'm trying to get enough thermal damping to prevent transient air currents from impacting the results. I'm currently using a sensor mounted in a copper tube which is pained white. The assembly is tie-wrapped to the frame of an equipment rack.