Short range device
A Short Range Device (SRD) ( German about " device short- range " is) a special radio for voice or data transmission for everyone-radio applications , which has only a small range due to its very low output power. It therefore has a high level of electromagnetic compatibility and will not interfere with other HF devices.
The old name in Germany was also Low Power Device (LPD) ( German for "device with low power" ). The radio equipment used must undoubtedly comply with the relevant national legal provisions, which in turn partly refer to international standards. The distributor documents compliance with these provisions by affixing the CE mark . On request, he must be able to present a declaration of conformity for this.
SRDs are available in the following frequency ranges:
|149.0250-149.1125 MHz||Freenet is a product name of the Motorola company and refers to a radio application for everyone that was set up in 1996 at the insistence of the Motorola company in a section of the freed-up frequencies of the former mobile B network . This application is only permitted in Germany.|
|169.400-169.475 MHz||500 mW|
|169.4000-169.8125 MHz||10 mW, three sub-bands with different. conditions|
|433.05-434.79 MHz||Radio applications in this area were formerly called low power devices or LPD . Its voice transmission variants are now also part of the SRD as 433/434 MHz radio, but use is only permitted in Germany, Austria and the Netherlands in Europe. In Germany, the Federal Network Agency (BNetzA) no longer recommended that new two-way radios be placed on the market. There are still handheld radios in the 433/434 MHz range that do not require registration and are free of charge for short-range radio , so-called everyone’s radio .
Depending on the ambient conditions, the devices the size of a cigarette packet can achieve ranges of 0.5 to 2 km. The first LPD devices came on the market in 1995; have meanwhile been overtaken by the PMR devices available since 1999 , which transmit in the 446 MHz range and with similar purchase prices and dimensions can bridge up to 5 km with more transmission power. Since LPD devices cannot initially be distinguished from PMR devices, it is best to pay attention to the approval mark; While PMR devices only have the CE mark with a four-digit identification number, the LPD devices also have the CEPT LPD-D mark .
LPD devices broadcast on a common area ( ISM ) that is also used by various other devices and services, e.g. B. Medical devices, cordless thermometers, cordless headphones and mobile speed measuring devices (u. P80) from government agencies. This shared use can further reduce the effective range of the LPD devices, as no protection is guaranteed against disruptive influences. At the same time, the frequency range of this ISM band is primarily assigned to the amateur radio service as an amateur band .
On November 24, 2010, the Federal Network Agency published a new general allocation for so-called Short Range Devices (SRD). The new general allocation is limited to December 31, 2020. The shortened time limit for the 70 cm area until the end of 2013 contained in the old allocation - which suggested that this area "expires" - is no longer included in the new general allocation.
In the meantime, this general assignment has been canceled and replaced by a new general assignment by Order 43/2012, which takes into account the implementation decision of the EU Commission on the harmonization of frequency use by devices with a short range of December 8, 2011. The 70 cm area can now be used with the previous parameters and without any other usage restrictions until December 31, 2022.
|446.0-446.2 MHz||Analog and digital PMR radio with 8 or 16 channels in a frequency grid of 12.5 kHz or 6.25 kHz (digital) and 500 mW ERP transmission power. 446.0 to 446.1 MHz (8 channels / analog) are provided with a channel width of (12.5 kHz). Above (446.1 to 446.2 MHz) are 8 (at 12.5 kHz) or 16 (at 6.25 kHz) channels for the digital mode. The analog frequencies are currently released until December 31, 2022, the digital frequencies until December 31, 2016.
Analog frequencies in a 12.5 kHz grid, narrowband FM (NFM)Digital frequencies in the 12.5 kHz grid, TDMA , digital modulation in the DMR Tier I standard
|863-870 MHz||In order to reduce mutual interference, such as occur in the 433 MHz band, from the outset, the relatively new 860 MHz band has been divided into several sub-bands. A special use with special parameters is provided for each sub-band. The temporal usage indicated in the table (relative frequency occupancy duration or duty cycle in%) is defined as pro rata active transmission operation within a period of one hour at any point in time .
In addition to the general allocation for SRD, the BNetzA also defined allocations for "non-public radio applications for alerting purposes" in this frequency range.
|some frequency ranges above 2 GHz (2.45 GHz)|
- Wireless thermometer
- Wireless alarm systems
- "Internet of Things", e.g. B. Sigfox
- Interface description SRD (PDF) Federal Network Agency
- SRD frequencies (PDF) Federal Network Agency
- General assignments Federal Network Agency
- General allocation on mikrocontroller.net
- General assignments Federal Network Agency; Short Range Devices (SRD)
- bundesnetzagentur.de ( Memento of the original dated February 2, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF)
- bundesnetzagentur.de, 'Vfg 30/2014' ( Memento of the original from August 3, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF)
- bundesnetzagentur.de (PDF)
- Sigfox. Retrieved September 9, 2016 .