I often have signal loss and when I do have one the strenght seems low between 18 and 30 on both SD Satellite 119 Transponder 16 and dish system 500 and HD Satellite 61.5 Transponder 17 and dish system 500 using the VIP reciver, If the problem was on one or the other I might think a obstructed view however being on both I wonder if the dish system 500 might be the problem? I have checked the outside connections.
Sorry to hear about your signal strength issues Mich, those are fairly low signals and can definitely potentially cause issues with the service. If you are absolutely sure something is blocking the line of site to the south western sky you can try clearing up the dish's view. Another good step to try is just walking along the cable path and making sure all cables and tightened down and not loose.
Assuming neither of those things help and signal remains low, you should call our technical support team at 1-800-333-3474. They can work with you over the phone to do some basic troubleshooting, and if no progress is made, help you take the next steps on getting a technician to look at the system.