Legal repeaters explained
StellaDoradus 1002 series compliant repeaters
All electronic equipment sold in Europe must clearly bear the “CE” mark. This means the equipment passes all European laws that apply to that type of equipment.
For repeaters, the “Radio Equipment Directive” applies. Below are the 8 main test modules a repeater must pass in order to meet European regulations.
Of course it is very easy to just label the equipment with the CE mark, even if it does not actually pass the relevant tests.
It is very difficult for the European regulators to police all false CE mark claims, especially if the equipment is sold on Amazon or through other websites. Most of these repeaters are of Chinese origin sold through Amazon or professional looking websites and shipped out of Hong Kong. These sellers make a big effort to make their web sites look as if they are European companies and falsely mark their repeaters with the CE mark.
Important tests a repeater must pass in order to be legal and allowed on the market.
- Operating band unwanted emissions
- Spurious emissions
- Maximum output power
- Input intermodulation
- Out of band gain
- Adjacent Channel rejection ratio
- Output intermodulation
- Network protection features
Only Stelladoradus repeaters pass all of these tests and are therefore the only legal broadband repeaters available in Europe.
Why is it important to have a compliant repeater?
The reason is “Interference”.
The European regulations are there to ensure the repeaters do not cause interference on the mobile phone networks. Interference causes other mobile phone users to experience increased level of dropped calls, and sometimes a complete inability to use the mobile phone network.
Every year European regulators confiscate many thousands of illegal repeaters. The operators base stations detect the illegal interference, the operator then contacts the Communications regulator, the the regulator must then find the source of the interference which is often very costly. When found, the repeater will be confiscated.
Reasons for the Chinese repeaters not passing the European Radio Equipment Directive:
- In order to keep costs down, the chinese repeater manufacturers leave out very important repeater control circuits.
- They have no automatic gain control (AGC). This means that the output power of the repeater keeps increasing regardless of the input signal level. This causes many of the failure modes seen above.
- In order to keep cost down, the Chinese repeater manufacturers leave out expensive filters. This causes the failure of “out of band gain”. There are many new M2M (machine to machine)bands operating just outside the mobile phone bands. These are interfered with by these bad repeaters.
- They have no “oscillation” control. This causes very serious high power interference. It is caused by the indoor and outdoor antenna being installed too close together. It is a similar effect to the one you hear when a microphone is placed too close to a speaker and you get very nasty feedback sounds. The repeater should automatically fix this.
- “Uplink switch off”. The amplifiers on the uplink in the repeater should automatically switch off when the repeater is not in use. All repeaters create very low level uplink unwanted emissions. For a single repeater this is not a problem, but if many repeaters are installed in the same area, the combination of all this noise can create problems. The solution is to switch off the uplink amplifiers when your phone is not being used, which is actually most of the time.
- If a repeater is installed close to a base station, it should automatically reduce its gain in order to ensure the base station never detects its presence. The repeater has to have the ability to measure how close it is to any base station and to the gain adjustment. The user should never need to know this is happening or be able to interfere with the automatic adjustment. It should all be automatic.
- All the above network requirements require the repeater to be controlled be a sophisticated micro-processor running advanced software. None of the Chinese repeaters have any control or microprocessors. They are just simple amplifiers, with no intelligent filtering or processing or control.