Since this has started over two weeks ago, we haven't had any snow, any rain or wind or any other weather issues. There is no snow on the dish. There is no ice on the dish. I do have a lot of pixellation issues periodically, which may be related to what is going on, or something different entirely.
I want to post here to relay what happened to me with 530s, as there's some similarity to your issue in that, no matter what I did, the problems never ended. We ended up having five 530s, all brand new replacements. Every time we had one, something would go wrong with it in short order -- usually it was freezing, sometimes corrupt recordings, black screens, spontaneous reboots...you name it. We heard the "plug it into the wall," "move it somewhere else," "let's try a reset," "let's switch the cables around," everything. I became bosom buddies with a guy from technical escalation.
Anyway, as it turns out, the first three 530s might have had nothing specifically wrong with them. However, the installation (which had been done a few years prior before 530s existed) was faulty. But when technical escalation sent out a service person, he was the same one who did the original installation and he found nothing wrong. So problems kept happening. Technical escalation even footed the bill for a voltage regulator, in case the problem was brown outs. When we got 530 #4, I suggested a *different* service person come out. When that happened, he discovered that one of the cables running under the house was hanging by a thread with loose barrel connectors and that the dish was barely attached to the roof. Once these things were fixed, #4 worked for some time. But then it developed a completely *different* problem, which was the sound simply stopped working. Thus replacement #5. We had the same problems with that one that we originally had. Technical escalation suggested turning off the live on disk as a permanent feature. Meaning that we should only do two of three things at the same time between having the live on disk on, recording something and watching a recording. We still have that 530 two years later. We've had some problems with it here and there, but overall it's been fine.
But, had our installation been correct in the first place, we might only have needed *one* 530, not five.
I'm writing this so you'll know that it's possible a variety of circumstances, not one single circumstance, could be causing your 630 problems. And it really could be the 630s, or the installation, not your environment, nor anything at all like that. There are people on this forum who have had many, many replacement receivers. Is it unusual? Perhaps. But not unique. I'm sure you can get a good one eventually.
But what you really need is to speak to technical escalation. Beware...no matter what, those guys will probably think your 630 can be fixed, they hate sending out replacements because they're simply in LOVE with the 630, really. BUT they know everything about 630s that there is to know and, if there's a way to fix it, they'll figure it out.