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Rider on the Storm
not Sweden

1 edit
reply to nunya

Re: CATV issue- box freezing and reboots.

said by nunya:

You mentioned the channel is in the 741 MHz range, which is probably the higher end of Charters spectrum usage (in the olden days, 741 MHz was channel 115).

I asked about the frequencies, as every time I checked the diagnostics screen after an issue, the frequencies changed! I thought that was a symptom, but tech said that is normal, it's called digital switching cable (I think..) where the cable box locks onto a different frequency if someone else is using that frequency. Sprout, where I saw these freezes happen yesterday, reported to be on 741, 570, 591, and 753 MHz... all within the same day! But apparently that is normal given the infrastructure. And the freezes happened on both 5XXMHz and 7XXMHz.

How long is the drop to your house? You did mention it's RG11. Is it over 300 feet? RG11 is great when RG6 just wont cut it, but it does have it's limitations as well. It's not really that significant a step above RG6 (contrary to what many people, even CATV techs, believe).

Pole to house is about 110'. I have 2" underground conduit running to the house and I specifically had it at least 12" away from house electrical conduit. I think it's almost 2' away underground actually. RG11 is used here for underground installs, even in conduit apparently.

EDIT: And the drop has already been replaced once in the past... this happened both before the drop change and now after. So coax drop is not the problem.

What I'm driving at: even if you have a nice acceptable signal at the tap, send it down 350' of RG11 and the upper frequencies are going to slide off. You'll have around a 10db loss @ 741 MHz over 300' or RG11. If the originating signal is nice enough, you can add an amplifier first thing and boost it back up.
But if the originating signal (and this could even be in the CATV distribution plant) is crap that's just been cranked up - you see the problem.

I see what you are saying. I recorded power levels as reported by the boxes over the day... here's what I got:

579MHz 3dBmV
591MHz 3dBmV
753MHz 7dBmV

I didn't record the 741 MHz power level.. but I would think it's around where the 753MHz level is. Tech checked power signals at the house immediately before the grounding block yesterday (in a variety of MHz ranges, including 700+), and they tested at appropriate levels, and checked for errors and got none (at least at the moment it was checked). He did say it was a short run for RG11, but didn't see anything that would be causing a problem.

I would ask the technician *specifically* what the signal levels are at the ground block. Especially in the 700-800 MHz range.
Another "habit" that I am guilty of, as are many cable installers, is keeping the modem off the amp. E.G., splitting the signal to the modem first, and then sending everything through the drop amp. This is because many amplifiers do not play well with modems (yes, I know they *should*).

Yeah, my modem and MTA are split immediately before the amp, and they've been flawless as far as I can tell. Tech and I went round and round with theories, but he said he thinks we both were overthinking this one. He said if something is fouled up in the head end... and given that all three boxes locked up simultaneously... a big "tell" if you will), then chasing down house wiring isn't going to help... but it may be needle in a haystack time at the head end.