SARAD GmbH
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User Manual RTM1688-2 06-02-2019.docx
antenna cable into the enclosure. It is not possible to operate the antenna inside the
enclosure. The metal walls will attenuate the GSM signal dramatically.
The modem is supplied by the external power socket and will work only if an external
voltage is present. The power cable has to be connected to the power socked of the modem
beside the antenna connector.
Please note that the modem consumes a multiple of power compared with the instrument
even if it sleeps. The direct connection of the modem to the battery should be realised only
if the continuous recharging is provided. Discharging the battery below 11 V may damage
the battery and should be prevented by an additional voltage level switch.
Connection of the Soil Gas Probe
Connect the soil gas probe only if the measurement has been stopped before or if the power
supply has been interrupted (both, battery and external DC). Check the correct fit of the
plug. The cable must be no longer than 10 Meter. Keep it as short as possible depending on
the installation conditions.
Please read also the hints for installation and operation of the soil gas probe given in the
application note AN-007.
Specifications differing from the Standard Version
Sampling
large area diffusion membrane
Response time (fast/slow) dependent on the used membrane
60 / 180 Minutes (125µm Silicon rubber)
Sensitivity (fast/slow)
0.8 / 1.8 cts/(min*kBq/m³)
Battery life time
approximately 2000 hours (without modem)
Dimensions / Weight
Electronics enclosure 230mm x 280mm x 111mm / 4kg
Soil gas probe
76.1mm dia. x 125mm (without socket); 650g
For further specification read the separate data sheet.
Statistical Error (for non-mathematicians)
The radioactive decay is a statistical process. That means, even if the Radon concentration is
constant over the time, the number of decays N counted within several intervals of the same
period will be different. N will vary around the mean value of all considered intervals.
Considering an infinite number of intervals would lead to an average which one indicates the
“true” result of N. For a single interval, the value of N will be either below or above the
“true” value. This observed deviation is covered by the term “Statistical Error”.
Therefore, each serious measurement contains beside the calculated Radon value the error
band for a stated confidence interval. The commonly used confidence intervals are 1, 2 or 3
Sigma (
) which refer to a likelihood of 68.3%, 95.45% and 99.73%.
