29 January, 2021
You have poor reception, you miss phone calls and even your WhatsApp messages can no longer be sent. The situation is actually the same as when you did not have a GSM repeater yet. It seems that your GSM repeater has stopped working at all. The most common cause is interference.
- What is interference?
- How does interference occur?
- How do you recognize interference?
- How do I resolve interference?
1. What is interference?
Interference is the interaction or opposition of several waves at the same time and place. It occurs because each antenna both sends and receives signals. The indoor antenna sends and receives a signal and the outdoor antenna receives the signal transmitted by the indoor antenna or vice versa. The problem that then arises is that the signal ends up in a loop. You can compare this to singing from a microphone.
2. How does interference occur?
Interference therefore occurs because the indoor and outdoor antenna pick up each other's signal. This happens because they are close to each other or because there is too little mass between them. Windows and other thinner materials also ensure that the indoor and outdoor antenna can easily pick up each other's signal.
3. How do I recognize interference?
Interference becomes obvious quite quickly if you have poor reception, but it is also visible on the GSM repeater. The GSM repeater then indicates a red light in the event of an alarm or flashes green. If you see this, you should move quickly to the solution as interference is causing interference on the carrier's network and we would like to avoid that.
4. How do I resolve interference?
Solving interference can sometimes be tricky. Often the cause of the problem cannot be directly identified, which means that several steps have to be taken.
Step 1 - Place the antennas as far away from windows or other openings as possible
The first step is to move the antennas away from windows or other openings. This is because signal can easily penetrate through glass, which can easily cause interference. Very often the culprits are the skylights or doorways. With wall antennas you can place the back of the wall antenna to the window, but it is best to move it.
Step 2 - Create more distance or mass between indoor and outdoor antenna
The second thing you can do to resolve interference is to move the indoor and outdoor antenna farther apart. Place the indoor antenna in another room or behind a thick cabinet. By placing more obstacles between the indoor and outdoor antenna, more mass is created between the antennas, which blocks the signal.
Step 3 - Make sure the indoor and outdoor antenna do not face each other
The third solution is quite simple. Make sure that the indoor antenna and the outdoor antenna do not get into each other's signal waves, i.e. make sure that they do not point over each other. For example, your indoor antenna is facing north and your outdoor antenna is facing south, but the outdoor antenna is facing north. Then the outdoor antenna points over the indoor antenna and again the chance of interference is high. In this case, you can relocate the indoor antenna or direct the outdoor antenna to another cell tower.
Step 4 - Receive less signal with the outdoor antenna
Are you unable to resolve the interference with the above steps? Make sure that the outdoor antenna receives less signal. If the outdoor antenna receives less signal, the antennas will also transmit less signal, reducing the chance of interference.
You will receive less signal by not pointing the outdoor antenna directly at a transmission tower, so turning your outdoor antenna. You can also choose to aim at a cell tower that is further away. You can also lay your antenna flat on your roof or wrap the outdoor antenna with aluminum foil. If you are still receiving too much signal, you can place attenuators between the GSM repeater and the outdoor antenna.
Step 5 - Muting the signal with dip switches
Do you have an older GSM repeater? Then you also have dip switches on your device. Allows you to mute the signal. Check at which frequencies the alarm light is red or flashing green and start muting 1 dBm at both the UL and the DL. Add 1 dBm each time until the lights are solid green.
This is not possible with the newer devices, because they have the Smart function. The smart function automatically mutes signal to ensure there is no interference, but can only attenuate up to a certain number of dBm. Because of this it may be necessary to go through steps 1 to 4.
Did the above tips not help you resolve the interference and do you still have a red light or a green blinking light? Please contact us as soon as possible and we can help you solve this.
