Diagnose this wacky cable problem

Factual Questions
1

A few weeks ago, my cable modem started having difficulties getting connected, so I called the cable company. The guy came out and the cable inside the house looked fine. However, the signal was bad, as evidenced by the modem not working and the lower numbered channels being “snowy” on the TV.

 He went outside to test the connection and as soon as he unscrewed the connector and replaced it, the snow went away on the channels and the cable modem started working a treat.     Well, "corrosion on the connector" was the diagnosis, I said, "huh, well I could have done that" and all was well.    For a couple of hours until everything went snowy again.    So for a week or so, every time it failed,  I'd go outside, unscrew the connector, rescrew it, and everything would work fine for a while.   Then I got tired of doing this, called the cable company again, and they came out and replaced the whole connector assembly.   New connectors on both ends, new fitting, new ground.     Since then, the modem has worked fine, but the lower channels have still been snowy.    So last night, in the spirit of experimentation, I went out, and did the unscrew the connector/rescrew the connector trick again.    And sure enough, the reception cleared right up, at least long enough for me to leer at Jennifer Garner's various aliases.

 Given that the connectors are brand new, it's not likely that this is a problem with corrosion or bad connections.    But what could it be?    My theory, which tends towards the baroque and is based on no scientific theory whatsoever is that there's some wacky capacitance thing going on in the cable that gets released when I unscrew the connector.

 One additional bit of information is that the pole across the street where the cable comes from did get whacked with lightning last spring (killing my old cable modem in the process).

Any ideas?

2

I had a problem last year in which my cable modem service would come and go. Mostly go.

The inside connectors, modem, computer, etc, were fine.

A trip up the pole reveals numerous poorly installed traps and splitters on the line that branched into my house. The repair guy fixed that mess and it’s been smooth sailing ever since.

Have the repair guy check this out on his next trip.

3

I wonder if this could be related to grounding. As in, there’s a buildup of static electricity on something, and then when you go fiddle with it, you discharge the static, making the problem go away for a while. I’m really not sure how much effect static electricity could have on cable reception. Next time you have the problem, just go out and touch the connector they replaced, without fiddling with it too much. If the problem goes away, you might need to check what the ground on the connector is actually attached to and make sure that it really is grounded.