No Signal on DVB Adapters

Signal loss on DVB adapters can be caused by weather conditions, physical cable problems, software configuration issues, or hardware failures. This article covers the most common causes and how to diagnose them.

Weather conditions

Weather has the strongest impact on satellite signal quality. Even a perfectly aligned antenna can lose signal completely during severe weather.

• Heavy rain or snow: signal may drop to zero during intense precipitation. This is known as rain fade and affects higher frequencies (Ku-band) more than lower ones (C-band).
• Snow on the dish: even a thin layer of snow on the dish surface causes significant signal loss. Keep the dish clear of snow accumulation.
• Strong wind: can physically move the antenna, causing misalignment. Check antenna position after storms.

Solar interference

Twice a year, in spring and autumn, the antenna, satellite, and sun align in a straight line. During these periods, the sun’s radiation overwhelms the satellite signal, causing temporary outages. Each interference event lasts about 10-15 minutes and occurs for several consecutive days. This is a natural phenomenon and cannot be avoided.

Driver issues

After a kernel update or server reboot, DVB drivers may stop working. To check if adapters are available, open the adapter settings in the Astra web interface and look at the adapter dropdown list. If the list is empty, the system does not detect any adapters.

Read more: DVB Driver Issues

failed to open frontend: Device or resource busy

Adapter is taken by another process. Maybe Astra started twice.

You may check which process uses Astra with next command:

lsof | grep adapter0

Example output:

astra 23068 ... /dev/dvb/adapter31/dvr0
astra 23068 ... /dev/dvb/adapter31/frontend0

• astra - process name
• 23068 - process PID
• /dev/dvb/adapter32/... - path to the adapter

Adapter numbers changed after reboot

When a server has different adapter models installed, their order may change after a reboot. For example, an LNB receiving from satellite 13E was on /dev/dvb/adapter0, but after reboot it became /dev/dvb/adapter8.

To check if this is the issue:

1. Temporarily disable non-working adapters in Astra
2. Try changing adapter numbers in their settings to match the new order
3. Enable adapters one by one and verify signal reception

5G interference with C-band

In some countries, part of the C-band (3.4–4.2 GHz) has been reallocated for 5G mobile networks. This can cause interference with satellite systems that still use the lower C-band frequencies (3.7–4.2 GHz).

If you experience signal degradation on C-band after 5G towers appear nearby, consider installing a 5G filter on your LNB to block terrestrial interference.

Cable and connector issues

Physical cable problems are a common cause of signal loss:

• Damaged cable: cuts, kinks, or crushed sections in the coaxial cable
• Water ingress: moisture inside the cable or connectors, often from poor weatherproofing at outdoor connections
• Short circuit: the cable shield touching the center conductor, usually at poorly made F-connectors
• Loose connectors: corroded or improperly tightened F-connectors at the LNB or receiver
• Cable too long: excessive cable length without proper amplification causes signal attenuation

To diagnose cable issues, use a satellite signal meter:

1. First, connect the meter to the cable near the server. If no signal, the problem is in the cable run
2. Then connect the meter directly at the dish. If signal is present here but not at the server end, the cable or connectors between these points are faulty