Cable box data at cable company.

I've been having pixelation and audio dropouts on the cable at my boat. I called the cable company and they read the data on my box. Cisco RMG 100 with PS LiteON Model PB=1300-012SA. They said the signal strength is ok and the power is a little low, but ok. He said 5% low. Signal that I read was -5dbmv to -11dbmv. I ask, "what do you mean my power is a little low?" He said the AC is low. I said, how can you see that, it is powered by a switching supply and regulated. I suggested that many supplies will work from 80V to

220V. It is separate power supply. I don't know what low means to the cable company, I haven't checked lately, but I expect my AC is above 117V. Do you see any way the cable company could know my AC voltage? Mikek

PS. they loaded updated software, it didn't fix the problem.

Reply to
amdx
Loading thread data ...

If it uses the typical wall wart I would say they are measuring the DC voltage on the board, not the AC line voltage.

Maybe he means the signal power received from your unit?

--

Rick
Reply to
rickman

No, it was the ac voltage, I discussed it with him. I just don't see any way he could tell. Maybe, they monitor the 12V from the PS, and he just described it wrong. Mikek

Reply to
amdx

Maybe the caps in the box are going TU. Can you open it up and check ripple on any supply(s).

I have had four boxes from verizon go bad due to caps. You can look through the vents and see the bulging tops.

Reply to
Tom Miller

Google says this is a standard-looking "pregnant snake" power supply.

120 V AC in, 12 V DC out.
formatting link

I'm almost 100% sure he is confused. The cable box probably does measure the RF signal strength, but not the line voltage. If you've ever successfully built a crystal set, you know more about RF than about

98% of the people working at the average cable TV company.

Well... the power supply *could* be measuring it and imposing some digital data on the +12 V line to the cable box, but... I've never heard of that. Doesn't mean it can't be happening, though. If it had one of those connectors with the third "data" pin inside the barrel (see recent-ish Dell laptops), then *maybe*, but that appears to be a standard 2-conductor plug.

Matt Roberds

Reply to
mroberds

Or just plain adding a conductor to the cable. The PSU on my laptop does that. I tried using an inexpensive 95 W PSU to power the laptop instead of the $130 135 W unit and a popup comes up peridically saying the PSU isn't big enough! Or course, as long as I keep dismissing the popups it keeps running just fine.

--

Rick
Reply to
rickman

Please check your typing. It's an RNG 100, not RMG. The power supply is PB-1300-02SA. It was first released in early 2013, so it's not too old.

I'm more familiar with the cable modems, but as I understand it, the target range for the set top boxes is -5 to +5dBmV. I can't find the specs, but I think they claim -10 to +10dBmV. I would call -11dBmv more than a "little low". There's the problem.

Huh? dBmV is also a measure of power. Is someone mixing measurements and units of measure? There's no way you will have low AC power. The Liteon power brick is generally a good brand. If you have a scope or DVM handy, check if there's a AC coming out of the power brick when it's terminated by the set top box. Also, if the DC power to the RNG100 were low, the red power light would flash.

The specs on the Liteon PB-1300-02SA are: INPUT: 100-240V~,50/60Hz, 1A OUTPUT: 12V 2.5A 30W Connecter size: Int. Diameter: 2.50mm, Ext. Diameter: 5.50mm Unless your line voltage drops below 100VAC, you're not going to have low output. It think support was referring to low receive power in

-dBmV.

Yep. The box is monitored and run by SNMP3. Just about everything related to i/o and performance is listed in the SNMP MIB. I couldn't find the MIB online, but recalling similar devices, the 12V DC input is monitored with a good/no-good value. There's no way they can monitor the 117VAC line voltage.

Yeah, they always do that. Give support something to do while they figure out what to do next.

Drag the box over to where the cable arrives from the pole or hole. Plug in directly with a known good cable. Measure the levels again. If they look normal, start testing your inside coax wiring, which I would guess is full of water or corrosion. Same with inspecting the connectors. If suspicious, get some SNS1P6U push on connectors (NOT crimp ring connectors) and replace them. If there's any RG-59/u in the system, rip it out replace with RG-6/u. Unscrew any splitters, dividers, or directional couplers in the system and shake them. If it sounds like there's water inside, replace with

5-1000 MHz. If you're not sure of the wiring topology, post a drawing somewhere and I'll pass judgment.
--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
 Click to see the full signature
Reply to
Jeff Liebermann

I've checked my box myself on comcast. I had to open a link.

Greg

Reply to
gregz

On Wed, 16 Sep 2015 17:37:28 -0400, rickman Gave us:

What part of "85 to 220" do you not understand?

An autoswitching SMPS has NO VARIANCE in its DC output if fed from an AC line between those two values.

I thought you claimed to know electronics. Do you not even know what the terms "Low line" and "High line" even mean?

The Dc voltage fed to this device should be the same throughout that range of AC input voltages, and not only that, the PC assembly being fed the DC the supply makes should also have a range of values throughout which it will operate with full function. Having a piece of software to make such a declaration is dumb and having an untrained idiot at the customer service desk to spout stupid shit like "your voltage is low", because it falls below some number some other retarded f*ck listed to her on her "customer response" sheet is even more stupid.

The SIGNAL of -11dBmv is a little low for a signal feed from a cable distribution tap. So if anything, the CABLE COMPANY has a Line Extender set point problem if they cannot get a stronger signal delivered to a cable tuner's input jack/port.

I would suspect the "house drop" feeding the lightning arrestor (if there even is one), and demand that the lazy cable company get one of their stupid techs on site to make sure that the feed signal is hot enough. They typically want to blame the customers side of said lightning arrestor ground block, but I would not take any of their Obamanized bullshit. The asshole they send should also START with looking at the outside hardware and the drop, BEFORE he starts on the guy's gear inside, which they ALSO like to do ass backwards.

Reply to
DecadentLinuxUserNumeroUno

On Wed, 16 Sep 2015 22:00:25 +0000 (UTC), snipped-for-privacy@att.net Gave us:

Especially the customer service "techs". And easily most of the field trouble shooters. Half of them do not even know how to cut an F fitting right. I would start with examining every cut fitting from the pole taps in.

But to answer your thought... they DO have monitor hardware in the tuners and they do get more info than just the RF data.

Knowing what it means without their supervisor supplied cheat sheet is another thing (even with it), however.

Also, it should not impact a cable tuner if it is a 12V assembly to be driven from about 10 all the way to about 16 volts.

Reply to
DecadentLinuxUserNumeroUno

Hmm, I'm not at the boat so I can't check, but I think your correct. Old eyes, standing on freezer, ducking head away from ceiling, low light, ah, or maybe I just f$#%ed up.

Cable guys number was anything above -15dbmv was ok. When the system was first installed we had some minor pixelation problems, but they resolved themselves.

My boat is docked at a non original slip, I had to run my own electric, phone, and cable from a power pedestal about 120ft away. Meaning there is a 3 way splitter instead of the original 2 way and the long cable run.

He was talking two different measurements, signal power and AC line voltage level. At this point I don't think he was correct, I told him many Switching supplies will output a regulated voltage from 80 to 220 volts. He said, He understood that but that's what his equipment told him.It looks like the numbers for this supply are 100 to 220 volts.

Again he named two different specs. We all think he was wrong at this point.

It's all one piece of coax from the dock pedestal into the cable box. I might gain a db if I replaced the 3 way splitter with two 2 way splitters, and feed my boat from the first in splitter. It is possible I have water ingress, the cable comes off the dock, dips in the water and then up through the floor of the pontoon boat floor up the the Cable box. It's RG/6, cable company supplied. One other thing, the problem happens more often in the late afternoon, but not only in the late afternoon. It's been a year since I've seen the other two taps at the pedestal used, I may just remove the 3 way and add a barrel to run mine direct, just as a test, then I'll forget to reverse this until someone complains. However, even when the signal is up to -5dbmv, the signal still pixelates, so, the solution is still up in the air.

Mikek

Reply to
amdx

I don't know what that means.

Mikek

Reply to
amdx

I'm usually right, except when I'm wrong. Google came back with the correct model numbers.

Not under all circumstances. What's happening is that your 120ft long run is creating "tilt", where the cable loss at the lower frequencies is less than the cable loss at the higher frequencies. The specs for tilt on digital is something like 3dB variation from end to end or maybe less. You're going from -11 dBmV to -5 dBmv or 6 dB variation. So, you have two problems. Too much cable loss and too much tilt.

What makes this important (or worse) is that the digital tuner supplies AGC based on the average RF signal levels for all the channels. There are various reasons for this, but the big one is that it's simple and cheap. Just rectify the entire cable band 40-1000 MHz and since the alleged variation in signal levels are minimal, it should be just fine for any channel. Well yes, but in your case, it's not going to work with 6dB variation in signal levels.

Incidentally, I found some specs on another cable box. -15 to +15dBmV maximum signal level range. So, it should work.

Think about a CATV amplifier. Slope or tilt compensation might be useful, but necessary. Offhand, (without calculating) methinks the difference in signal levels should NOT be 6dB over the frequency range as you're experiencing. It might be the CATV feed, but my sense of smell suggests something wrong with your derrangement.

3 way splitters are rare. My guess(tm) is that it's really a 4 way splitter. Do you have the un-used port terminated with 75 ohms?

I have yet to see a wall wart type power supply with line voltage monitoring. Besides, there aren't enough wires in the interconnecting cable to do it.

I can't tell you where to go from here. Basically, you have two choices. You can take careful measurements or you can sustitute parts of the system. Removing splitters is a good place to start. The signal levels will change with the temperature, mostly because the ALC circuitry in the pedestal and pole top repeaters are not perfect and do change level/gain with temperature. If you have a dozen amps between the fiber to coax transistion and your vessel, and easy is gain stable to within 0.5 dB, you can easily produce a 6dB variation. It's not really that bad, but I think you can see how it works.

If the signal falls apart at -5dBmV, then purchase a line amplifier and see if the target value of 0 dBmV offers an improvement.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
 Click to see the full signature
Reply to
Jeff Liebermann

I'm usually right, except when I'm wrong. Google came back with the correct model numbers.

Not under all circumstances. What's happening is that your 120ft long run is creating "tilt", where the cable loss at the lower frequencies is less than the cable loss at the higher frequencies. The specs for tilt on digital is something like 3dB variation from end to end or maybe less. You're going from -11 dBmV to -5 dBmv or 6 dB variation. So, you have two problems. Too much cable loss and too much tilt.

What makes this important (or worse) is that the digital tuner supplies AGC based on the average RF signal levels for all the channels. There are various reasons for this, but the big one is that it's simple and cheap. Just rectify the entire cable band 40-1000 MHz and since the alleged variation in signal levels are minimal, it should be just fine for any channel. Well yes, but in your case, it's not going to work with 6dB variation in signal levels.

Incidentally, I found some specs on another cable box. -15 to +15dBmV maximum signal level range. So, it should work.

Think about a CATV amplifier. Slope or tilt compensation might be useful, but necessary. Offhand, (without calculating) methinks the difference in signal levels should NOT be 6dB over the frequency range as you're experiencing. It might be the CATV feed, but my sense of smell suggests something wrong with your derrangement.

3 way splitters are rare. My guess(tm) is that it's really a 4 way splitter. Do you have the un-used port terminated with 75 ohms?

I have yet to see a wall wart type power supply with line voltage monitoring. Besides, there aren't enough wires in the interconnecting cable to do it.

I can't tell you where to go from here. Basically, you have two choices. You can take careful measurements or you can sustitute parts of the system. Removing splitters is a good place to start. The signal levels will change with the temperature, mostly because the ALC circuitry in the pedestal and pole top repeaters are not perfect and do change level/gain with temperature. If you have a dozen amps between the fiber to coax transistion and your vessel, and easy is gain stable to within 0.5 dB, you can easily produce a 6dB variation. It's not really that bad, but I think you can see how it works.

If the signal falls apart at -5dBmV, then purchase a line amplifier and see if the target value of 0 dBmV offers an improvement.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
 Click to see the full signature
Reply to
Carl Ijames

I need to plead some ignorance here. I broached this subject with he cable rep, by asking, "what is the highest frequency channel? Thinking I could find the worst loss channel to monitor. He said do you mean highest bandwidth channel? At that point I was ignorant, is digital cable setup the same as non digital, meaning you still have a frequency

for each channel that is modulated in some fashion.

I would still like to know the highest and lowest frequency channels to compare against each other. btw, he said ESPN is the highest bandwidth. ??

I didn't explain that well so, I probably a different problem than you suggest, this variation (from -11 dBmV to -5 dBmv) happened on a single channel, while I was monitoring the level. It happened multiple times over days.

I specifically ask for a 3 way when the tech installed my drop, hoping for less loss. I already had concerns about the long cable run and losses.

That's a little more than I could do now a days, I would need the cable box and the TV to read the signal. The marina management has tightened up since the ex dock master had a $279,000 shortfall and was lucky to get out off with out a jail term, but did lose her 28 year city pension. That was part of the story I've told about the city subsidizing my competition, months of slip rent and fuel on credit that never got paid. Also didn't make his quarterlies or his boat payment. The lack of boat payment saved us, the owner finally took it back.

I can't power an amp at the pedestal, it would need to be at the lossy end, see a problem with that?

Thanks, Mikek

Reply to
amdx

On Thu, 17 Sep 2015 08:55:08 -0700, Jeff Liebermann Gave us:

A 120 ft cable drop is not all that big as long as it is RG6 at the tap at the distribution point is set fairly hot.

Reply to
DecadentLinuxUserNumeroUno

Correct:

Maybe. It depends on how much tilt. If there was an unterminated length of coax in the system, even with the isolation provided by Wilkinson divider type splitter, there could still be a substantial dip or peak in the frequency response. With 256-QAM a 6 MHz channel can carry 38.4 MHz of video (two 1080p HDTV channels per 6 MHz RF channel). With that many points in the constellation, any in band tilt (slope), group delay, or oddities is going to cause decoding problems.

Actually, I may have made a bad assumption. From the original posting, I can't be sure that the original mention of: "Signal that I read was -5dbmv to -11dbmv." means that it varies across the frequency range, or if it changes every time he looks at the set top box built in diagnostics. I'm assuming across the frequency range, but that might be wrong.

My method is Learn By Destroying(tm). Y'er not going to learn much from me on CATV. I'm more into cable data, not video, but I know enough to dig out the details with Google.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
 Click to see the full signature
Reply to
Jeff Liebermann

try removing the 3 way splitter and see how that goes...

with the digital channels, the channel number you type into the remote is not the actual RF channel so it is hard to tell which "channel" is on the low end and which is high without a channel map.

Sometimes there is a "secret" combination of buttons you can press to get some diagnostic data and the channel map. Search for it for your converter on Google.

Mark

Reply to
makolber

CATV frequencies are neatly standardized:

formatting link
The highest frequeny is 1001.75 MHz.

All the channels at 6 MHz wide. You can cram two HDTV 1080i TV channels into one 6 MHz slot. I think (not sure) it takes more than one channel to broadcast BlueRay, which might explain why it's not done. Some channels pay extra because they use more bandwidth. ESPN is a good example because viewers got tired of not seeing the football move across the screen. SD channels are the worst, with I think 12 SD TV channels crammed into one 6 MHz wide slot.

40 to 1000 MHz. Yep, ESPN is a bandwidth hog.

Oops. I assumed it was across the RF bandwidth. If you're getting such variations in level, something is loose, falling apart, full of water, or badly corroded. It's suppose to be fairly steady and not change over a 6dB range. It can also be a failing set top box, but I doubt it. Find something that will measure the RF voltage on the incoming cable and see if it follows the same 6 dBm (or more) variations. If yes, then your CATV provider (Comcast?) is the culprit. If rock steady, then it's somewhere in your wiring, errr cabling.

RG-6/u comes in many flavors, mutations, and losses. If it was installed by Comcast, it's probably very good quality cable. I'll pick a loss chart at random: At 55 MHz, 120 ft will lose -1.88 dB At 1000 MHz, 120 ft will lose -8.18 dB So, if you're looking at this with a spectrum analyzer, you should see the slope or tilt. However, I don't think this is the root cause of your problem. It's the large variation in signal level what bothers me. That just doesn't happen in systems I play with. With a cable modem, I can usually setup the modem, nail down the cables, record the levels, SNR, etc for each channel, and come back months later and nothing much has changed.

Get some help or muscle. A push cart or hand truck, plus a long extension cord, should be sufficient.

Well, the basic problem is that the installer setup the signal levels at the pedestal. You had them add a 120 ft coax extension, which may be part of the problem. The 3 way splitter certainly doesn't help, especially if the unused coax cables or connectors are not terminated.

Some amps are powered through the coax cable. They're generally the more universal cable amps, often bi-directional, and usually containing a switchable slope compensator. I'll see if I can find one but right now, I need to run. Oh yeah, putting the amp at the TV end will work nicely for the lower channels. I'm not sure what it will do at the high end of the band. -8dB of loss is quite a bit and depending on the amp quality, might introduce some noise. I don't know but I would watch out for such problems.

Good luck.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
 Click to see the full signature
Reply to
Jeff Liebermann

Ya, channel numbers corresponding to the frequency. I suspect channel 2 is the lowest, but the last I knew, some of the middle channels were higher frequency than the upper channels. Cable system has channels in the 400s, all they way to 900, if you pay.

Yes, I might just need a new cable run, but I'll pull the cover off the pedestal tomorrow and see if anything looks bad.

It's not the physical part, it's just working on the marinas system. I can get away with a look inside the pedestal, but not having all the accoutrements sitting on the dock looking suspicious. I could just call the cable company and set an appointment and let them repair it. It might save a second call if I isolate it.

I think you have more faith that any installer setup signal levels than I do.

Reply to
amdx

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.