Digital satellite receivers such as those manufactured by Humax are used by satellite providers to tune in TV signals from an orbiting satellite and convert them into a format that can be watched as TV programming. Satellite receivers, like any other cable equipment, are not immune from certain intermittent technical issues like no signal or poor signal quality when changing channels. These issues occur for different reasons, so determining the cause can go a long way in deciding the most effective means of troubleshooting and resolving the issues.
Loose Physical Connections
There will be at least one, perhaps several, connections that connect to your Humax receiver from the satellite dish mounted outside your home. If any of these connections are loose, damaged or dirty, you will experience intermittent signal problems when trying to change channels. Coaxial cables connected to the "LNB In" and "RF In" connections on the receiver should be hand-tight, and the copper needle running through the middle of the cable should be straight, sharp, not dusty or dirty, and should be sticking out past the end of the coaxial connector by about 1/8 inch. After verifying all physical connections, attempt to change channels again in order to check for any improvements.
Poor Weather Conditions
Satellite TV service differs from "terrestrial" cable service in that it requires a clear, uninterrupted signal from the satellite in orbit to the satellite dish mounted outside of your home. Any precipitation, cloud cover, dust, fog or even celestial phenomena like sun spots and solar flares can affect satellite service to the point that you will see intermittent or no picture when changing channels. Check outside for any inclement weather that may be causing the signal problems.
Service Outage or Degradation
Just like other forms of satellite service, channel outages or service degradations can affect your service as you try and change channels. If you have any other Humax receivers in the home that are connected to the same satellite service, check the same channels on those receivers. If you experience the same poor or intermittent signal when changing channels, report the issue to your satellite provider as you may be part of a service outage.
Receiver Lost Communication with the Satellite
Satellite receivers will occasionally need to be reprogrammed so they can properly communicate with the orbiting satellite. This is a normal maintenance operation for a satellite receiver and is not necessarily an indication of a bad receiver. Contact your satellite provider for help repositioning the Humax receiver so it effectively communicates with the orbiting satellite.