starhouse,
Although this may be unrelated to your issue, signal strength can be affected by both the weather in your area and the weather at the gateway. Cloudy conditions, even without rain, can definitely affect the signal. The thicker and more dense the cloud cover, the more it can be affected, again, even without rain hitting the ground.
Again, I'm not saying that this is necessarily what is happening in your situation, as I see it's been an ongoing problem.
I suggest it's time for Hughes to replace all of the hardware that has ever been connected to the old coax.
There are some very weird things that happen with this service. Things that defy logic and understanding. Although I suffered with different problems than you for more than two years (with multiple hardware replacements and continual intervention by our advocates here and the "experts" they work with) absolutely no progress was made until the coax was replaced. This cured the second of my extremely odd persistent error conditions.
Still, the original low speed problem that plagued my Gen4 system since Day 1 rolled on even though "engineering" continued analyzing while claiming it didn't exist and/or couldn't be fixed because of a variety of reasons.
Another year+ beyond the coax replacement and another year+ of continual effort by Amanda, Liz and myself, it's finally fixed. What eventually fixed it was re-replacement of the modem/power supply and radio AFTER the coax and original ground block were replaced. These were the third copies of modem/PSU/ODU installed for me but now my peak speeds ranging down below 100 kbps are done. It's still not perfect because of the overloaded beam but just about anything is better than a 200-400 kbps average on any Sunday
No matter how good Hughes thinks (or wants us to believe) their network expertise and remote and/or on-site diagnostics are, my case history shows this to be the polar opposite of true. There are too many moving parts and the system is far too complex to be properly analyzed for every individual situation.
Amanda and Liz will work themselves to a nub trying to resolve our problems for us but the truth is, when they are given bad information by their network systems or those who run those systems, there are no solutions. I have so much respect for the Official Reps who help us in this forum but I feel so very badly for them because I know how much pure malarky is dished out to them to supposedly help them in their efforts to help us.
As for clouds/weather doing this to you, I don't believe this could be a factor unless you live right on the ragged edge of coverage for your beam. A thick deck of stratus clouds will drop my signal a few points. Massive cumulonimbus obscuring the view between my site and the satellite will drop my signal more than a few points but we're talking a drop from a severe clear peak of up to 140 down to 80-120. It's only heavy precip that takes me out of the game and depending on severity, SQF can go to nothing.
I hope you can get this solved. It's very unfortunate but the effort required for getting our Hughes service to function properly can approach the level of a part-time job.