Radio Dosimetry

The TELDOS telemetry system is used for the wireless transmission of dose and dose rate over distances of up to 500 m. This is the approximate maximum range outdoors. Obstacles like buildings will reduce range. Even within buildings range strongly depends on local conditions. Therefore the really achievable range has to be determined experimentally in each individual case.

Data are transmitted on the FM-modulated 70 cm band (433 MHz). FM modulation provides a high level of noise immunity. Data security is ensured by a checksum protocol.

Notes on the 70 cm ISM band (frequency range: 433.05 MHz - 434.79 MHz): The ISM band is a frequency range which has been allocated for wireless transmission of measurement values and remote control signals. However, this frequency range is used by other radio services and high frequency devices. Usually only devices with relatively low transmission power (lower than 25 mW, may depend on national regulations) transmit on this frequency band, and accordingly the transmission range is short. This means that, although interference is quite unlikely and depends on local conditions, it cannot always be avoided. Should any transmission interference arise from other radio services, try to use a different transmission frequency if available.

Up to 15 data transmitters can be operated with one receiver, where the data transmitters use slightly different frequencies. The transmitters are approved in accordance with the 17-TR 2100 regulations and can be operated free of charge. At the receiver's end the data can be visualised and evaluated by means of a PC, laptop or similar.

The TELDOS system is flexibly assembled from the following components:

  • The Data Transmitter 6150AD-DS is connected to the probe connector of a standard 6150AD meter, gets power through this connection, reads the data from the 6150AD's serial interface and transmits them to the Data Receiver 6150AD-DE. This turns the standard 6150AD into a »transmitting« 6150AD.

  • The Radio Dosimeter ALADOX-S transmits dose and some other data to the Data Receiver 6150AD-DE. Of course it would have been desirable to turn a standard ALADOX into a »transmitting« ALADOX with the help of some accessory. That accessory would be a compact transmitting dosimeter reader. Although technically possible, such a transmitting dosimeter reader cannot be made small enough. Therefore the ALADOX-S was created which is only slightly larger than the standard ALADOX.

  • The Data Receiver 6150AD-DE receives data from any combination of Data Transmitters 6150AD-DS (»transmitting« 6150ADs) and Radio Dosimeters ALADOX-S which must not exceed 15 units in total. The Data Receiver passes these data through a serial RS232 interface on to a PC. Through commands on that interface the PC also controls which frequency channel to receive, i.e. the PC »tunes« the receiver.

  • The PC Software TELDOS-M communicates with the Data Receiver 6150AD-DE (selects and reads the channels) and displays the measured values on the PC.

All transmitters involved (Data Transmitters 6150AD-DS and Radio Dosimeters ALADOX-S) must use different frequencies to avoid interference. Therefore the frequency of any transmitter can be set individually, which however requires to open it. Usually we do that setting for you. Should you already possess transmitters, please tell us their frequencies prior to new orders so that we can set the new transmitters to different frequencies.

The Data Receiver 6150AD-DE can only be tuned to one frequency at a time, not to several frequencies simultaneously. Thus the up to 15 transmitters cannot be received simultaneously, but one transmitter after the other according to a time slice method. For that purpose the TELDOS-M software tunes the Data Receiver through commands on the serial interface.

6150AD-DSThe Data Transmitter 6150AD-DS is connected to a standard 6150AD through a standard Probe Cable. It reads dose rate from the 6150AD's serial interface and transmits it to the Data Receiver 6150AD-DE. Power supply comes from the 6150AD so that the Data Transmitter does not need a battery of its own.

At one of its sides the Data Transmitter has two probe connectors wired in parallel. One connector is for the required connection to the 6150AD, and the other one can optionally be used to connect a probe of the 6150AD family, again with a standard probe cable. Then the probe's measurement is transmitted.

At first glance the Data Transmitter looks very much like one of our digital dosimeters. This is no coincidence because we use a modified dosimeter housing for manufacturing it.

ALADOX-SThe Radio Dosimeter ALADOX-S (»S« = »Senden« = German for »transmit«) is an ALADOX dosimeter extended by a radio-frequency transmitter allowing wireless dose transmission. Functions and operation are the same as for the standard ALADOX.

External differences become immediately apparent: The transmitter's antenna emerges from the left of the front plate. Consequently the »mSv« inscription had to move slightly upwards. The housing is larger because the transmitter needs additional space. For that purpose an additional battery compartment was attached to the bottom of the housing. The original battery compartment now accommodates the transmitter, and the additional compartment is now the battery compartment. This also increases the dosimeter's weight. Electronics and radiation detector are the same as for the standard ALADOX.

Although the part of the instrument responsible for measuring radiation does not differ from the standard ALADOX, it is nevertheless a different type, which means that the PTB type approval does not apply to the ALADOX-S. We did not aim at a PTB approval for the ALADOX-S because that considerable effort is not justified by the low quantities of this model.

The ALADOX-S differs in the following technical data from the PTB approved ALADOX:

  • Temperature range: -10°C to +55°C (that range is smaller than for the standard ALADOX because of the transmitter's smaller temperature range).
  • Battery life: approx. 100 hours with an alkaline battery (speaker off) (much shorter battery life than for the standard ALADOX because of the transmitter's additional power consumption).
  • Dimensions: height 128 mm (excluding antenna), width 60 mm, depth 23 mm.
  • Length of the antenna: ~175 mm.
  • Weight: ~195 g excluding battery, ~245 g including battery 6LR61.
  • Transmitted data: serial number of the ALADOX-S, current dose rate, dose, alarm markings (low battery, dose alarm, detector failure).

6150AD-DEThe Data Receiver 6150AD-DE connects to the RS232 interface of a PC. It receives the data from the Data Transmitters 6150AD-DS and/or the Radio Dosimeters ALADOX-S. The PC tunes the Receiver to the different frequency channels. This allows to receive up to 15 channels. The Receiver is powered by a 9 Volt battery (IEC 6LR61) which is included in the delivery. Alternatively the Receiver can be operated from the optional Mains Adapter 856.1.3. For the connection to the PC we recommend the Connecting Cable CK582 (DB-9 COMx, 1.8 m).

The PC software TELDOS-M   LS05-0001 communicates with the Data Receiver 6150AD-DE. You have to tell that software which channels you wish to use. Then the software will only scan these channels for data thereby avoiding unnecessary waiting for data on unused channels. The software selects a particular channel by issuing a command on the serial interface which tunes the Receiver to that channel, and then evaluates the data received on that channel. TELDOS-M offers these functions:

  • Display of dose rate, dose, device status in tabular form for each individual transmitter.

  • Progress of the measurement in graphic form. You can switch between dose and dose rate as well as linear and logarithmic representation.

  • Three adjustable alarm levels for both dose and dose rate.

  • Recording the measurements on hard disk.

  • Compatible with Windows® 98/2000/NT/XP/7/8/10.

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