I am not sure if this belongs here or in the Distribution forum but since this is the only forum that has any references to the equipment I have I figured I would try here first.

I have a protek 3201 but don't really know the first thing about it. I snagged it at a surplus shop thinking I could use it for WiFi tuning but I figured out later that it won't work for that (out of the signal range)

Fast forward a couple years and now I am running Rg6 in my house. I have figured out that I can use the 3201 to check my signal strengths and figure out how much amp I need effectively split my incoming signal.

Only problem is that I don't really know the first thing about what I am trying to do. I have the manual so making it work shouldn't be a problem, I just need to know the basics ie I want to do a signal sweep and I am looking for this kind of measurement.

I'd like to avoid dealing with having the cable company come out if can. If I can learn something in the process that would be pretty cool too.

Just do a reading of channel ~117 at the groundblock and do the math from there.

Just do a reading of channel ~117 at the groundblock and do the math from there.

As the unit will not lock on to Digital 256Qams, its not going to do him much good. It wasnt designed for CATV work in the digital age.

I'm just trying to figure out if I need to get a drop amp to be able to support all my rg6 runs.

I'm not necessarily trying to tune anything for specific channels. Looking more for things like "you want to do a sweep scan and make sure that you stay with in x and y and start at this frequency and end at this one".

I may be misunderstanding how this all works and maybe I need a crash course in rf signalling. Of course any information helps.

Looks pretty neat to me.

http://sigma.octopart.com/165939/datasheet/HC-Protek-3201.pdf

I think 256 QAM is normally sent numerically about 6dB below the NTSC value, when making the apples and oranges comparison between NTSC peak and 256QAM RMS.

Your meter has a narrowband (12.5 KHz) and wideband (180 KHz) mode. You'd add about 15dB to what you'd observe as the "plateau" of the digital, "boxcar" waveform at 180 MHz bandwidth, or about 27 or 28 dB to the narrowband waveform. One problem of using the narrowband resolution is that the waveform might be below the range of the meter.

You probably have analog signals going up to channel seventy-something. You can look at the highest analog channel and compare that height to the next digital channel, and figure that level is 6dB lower than the adjacent analog, and use that as your reference when looking at the high end of the spectrum, which might be weaker due to cable tilt.

As the unit will not lock on to Digital 256Qams, its not going to do him much good. It wasnt designed for CATV work in the digital age.
Not an issue at all. 256QAM is run ~6dB below the nearest analog channel. Just look at the highest analog channel on the system (most systems have a carrier at the high end of their bandwidth -- typically ~117 or 135 ) and you're set. If you need to know the QAM level, subtract 6.

Would the PLL work on 256-QAM? I thought the reason for the pilot signal on ATSC was to provide something for the PLL to lock on to.

Hmm, on second thought, answering my own question, tuners for QAM/ATSC/NTSC use the same PLL, so it must work.

Would the PLL work on 256-QAM? I thought the reason for the pilot signal on ATSC was to provide something for the PLL to lock on to.

Hmm, on second thought, answering my own question, tuners for QAM/ATSC/NTSC use the same PLL, so it must work.
The pilots in cable TV systems (analog) provide signals for the AGCs to lock onto in order to adjust the gain of the amps. That is why there are analog carriers at each end of the bandwidth (even systems that are all digital).

Not an issue at all. 256QAM is run ~6dB below the nearest analog channel. Just look at the highest analog channel on the system (most systems have a carrier at the high end of their bandwidth -- typically ~117 or 135 ) and you're set. If you need to know the QAM level, subtract 6.

Not the point. If he cannot lock on and read the S/N on the 256QAM, which is just as important as the signal strength, its not going to do him any good.

Okay so since I barely understood most of what was said I can recognize when I am in a little over my head.

I have decided to take advantage of the cable companies SPP which costs a paltry .99 a month. I will hook my wiring up using the splitters I have on hand and then call them when I have problems. This way someone with the proper equipment and training can figure it all out for me. I may see if I can buddy up with the cable guy and talk him into showing me a few things about my analyzer.


I appreciate the responses I am just not really understanding it all.

Not the point. If he cannot lock on and read the S/N on the 256QAM, which is just as important as the signal strength, its not going to do him any good.
His original post was concerning signal strength, nothing else. It's a pretty safe bet, though, that his system is in compliance with DOCSIS.

His original post was concerning signal strength, nothing else. It's a pretty safe bet, though, that his system is in compliance with DOCSIS.

His first post also said:

Only problem is that I don't really know the first thing about what I am trying to do.

I'd like to avoid dealing with having the cable company come out if can. If I can learn something in the process that would be pretty cool too.

Thus by his own admission he did not know he needed to be concerned with S/N, which he WILL need to be able to check especially if he doesnt want to deal with the cable company.

His first post also said:



Thus by his own admission he did not know he needed to be concerned with S/N, which he WILL need to be able to check especially if he doesnt want to deal with the cable company.
Whatever.

It sounds like before someone replaces or adds a splitter to add an outlet or an amplifier to add several, they need to check to see what their SNR is. That is nothing short amazing!.

I read of people here and in other forums that do just that all the time and never have I heard of an issue. I just changed the input level to my cable modem three times (changed out the D.C. twice)(yes, it actually reads the level of its QAM input signal as well as the SNR) What d'ya know--SNR never changed, even though the input level did. Could it be that there is little we can do inside our homes that will change SNR? SNR is determined more by equipment (headend and outside plant) as well as the outside plant itself, not by how many outlets someone has in their home. When a 4-way splitter is inserted, everything goes down by the same ~7dB -- not just the signal level leaving the noise where it was. When both change by the same value, SNR stays the same.

DOCSIS says no less than 35dB SNR, and you can bet that most cable companies that have services that are reliant upon a clean system that meets/exceeds those specifications want to maintain those services by maintaining those specifications.

prozach

Do you have a cable modem?

Whatever.

It sounds like before someone replaces or adds a splitter to add an outlet or an amplifier to add several, they need to check to see what their SNR is. That is nothing short amazing!.

I read of people here and in other forums that do just that all the time and never have I heard of an issue. I just changed the input level to my cable modem three times (changed out the D.C. twice)(yes, it actually reads the level of its QAM input signal as well as the SNR) What d'ya know--SNR never changed, even though the input level did. Could it be that there is little we can do inside our homes that will change SNR? SNR is determined more by equipment (headend and outside plant) as well as the outside plant itself, not by how many outlets someone has in their home. When a 4-way splitter is inserted, everything goes down by the same ~7dB -- not just the signal level leaving the noise where it was. When both change by the same value, SNR stays the same.

DOCSIS says no less than 35dB SNR, and you can bet that most cable companies that have services that are reliant upon a clean system that meets/exceeds those specifications want to maintain those services by maintaining those specifications.

Do you deny that SNR is probably more important than signal with digital channels?

I guess there are 2 ways to do things

1) Just do it and pray.

2) Do it right.

Glad you haven't seen SNR changes in your house. As for me, I've had cable techs replacing all kinds of things over the past several years when the SNR falls to a point where it causes errors.

As for 35db SNR, I have probably seen about 50 people's houses and level, checking on the STBs of friends all over the Country. I would say that I've seen certain channels below 35db SNR on virtually every system in America, regardless of the spec. Most cable companies don't get concerned until it hit 32db.

As for 35db SNR, I have probably seen about 50 people's houses and level, checking on the STBs of friends all over the Country. I would say that I've seen certain channels below 35db SNR on virtually every system in America, regardless of the spec. Most cable companies don't get concerned until it hit 32db.

Interesting comment. I can play any HD channel with my dvr from the cableco but my clear QAM capture card does not accept the channel if s/n drops below 30. My highest s/n is 31.

Interesting comment. I can play any HD channel with my dvr from the cableco but my clear QAM capture card does not accept the channel if s/n drops below 30. My highest s/n is 31.


and last I checked, 31 < 35 :D

Seriously though, you should be getting higher than 31 on some channels. In most cases the numbers should average 32 - 37 and for brief moments, possibly 38. Another reason why one needs SNR in a meter.

I am not a betting person by nature, but I believe I might just want to take this bet:

DOCSIS says no less than 35dB SNR, and you can bet that most cable companies that have services that are reliant upon a clean system that meets/exceeds those specifications want to maintain those services by maintaining those specifications.

A signal meter is probably overkill for prozak's needs. Signal loss can be estimated by cable length and number of splits.

Ordinarily, one begins with a two way splitter with one leg going to a cable modem and the other to the TVs. Simply hook up the TVs and see if they work. If they do, but if you want to see if you have any signal strength margin, then put an extra splitter or two on the furthest TV and see if that signal drop causes problems. if not, then you are good to go. If it does cause problems, then 10 dB of gain should give you a more than adequate signal strength cushion.

If you are using cable boxes with return signals, then you will need to use a preamp that has a return path in it.

A signal meter is probably overkill for prozak's needs.


A signal meter is probably overkill for virtually any end user. Signal Strength as well as a host of other usable information such as S/N Ratio, errors etc can be found in virtually every STB Diagnostic Screen. Unfortunately, that wasn't the question prozach posed.

Do you deny that SNR is probably more important than signal with digital channels?

I guess there are 2 ways to do things

1) Just do it and pray.

2) Do it right.

Glad you haven't seen SNR changes in your house. As for me, I've had cable techs replacing all kinds of things over the past several years when the SNR falls to a point where it causes errors.

As for 35db SNR, I have probably seen about 50 people's houses and level, checking on the STBs of friends all over the Country. I would say that I've seen certain channels below 35db SNR on virtually every system in America, regardless of the spec. Most cable companies don't get concerned until it hit 32db.
SNR is important, of course. But, I would not agree that it is more important than signal level. SNR is, is its acronym indicates, a ratio of signal to noise. Inserting a 2-way splitter drops the level of the signal by 3.5dB. It also drops the level of the noise by the same 3.5dB. The ratio stays pretty much the same. Might be a slight difference (maybe 0.05dB or so), but the ratio stays pretty much the same regardless of the actual levels.

Adding an amplifier will lower the ratio, as it not only increases the levels of both the signal and the noise, but it also adds a little noise of its own. Merely adding, subtracting, or changing out passive devices in a home, though, will not change the ratio of signal to noise. The only exception to that would be if the device being pulled out was a poorly shielded device. Then, the SNR could improve. The SNR at the groundblock is pretty much going to be the SNR at all outlets.

So, you're suggesting that if someone wants to add an outlet in a bedroom, they need to buy a >$1k analyzer just to see if it can be done. That should fit into your "do it right" category.

Can't say anything about numbers at other systems. I've read posts, too, that indicate an SNR of <35dB. The deal with specs is that if everything meets the minimum specifications, everything is all but guaranteed to work properly. That doesn't mean that that's a magical number that everything starts/stops working at. When numbers are below minimum specifications, it may work, it may not.

So, you're suggesting that if someone wants to add an outlet in a bedroom, they need to buy a >$1k analyzer just to see if it can be done...

Why waste a thousand dollars when you can pay Ed or me a couple hundred to do it for you?

A signal meter is probably overkill for prozak's needs.A signal meter is probably overkill for virtually any end user. Signal Strength as well as a host of other usable information such as S/N Ratio, errors etc can be found in virtually every STB Diagnostic Screen. Unfortunately, that wasn't the question prozach posed.
Wasn't that what I wrote back in post #11?

The OP wrote "I have figured out that I can use the 3201 to check my signal strengths and figure out how much amp I need effectively split my incoming signal." Then you turned into a debate about SNR and not only scared him away from doing something he could have done in a relatively short amount of time, but he now is going to increase his monthly cable bill just so he could have something done that an awful lot of people successfully do every day.

Guaranteed that the installer/tech that goes to add his outlet won't check SNR.

Wasn't that what I wrote back in post #11?

The OP wrote "I have figured out that I can use the 3201 to check my signal strengths and figure out how much amp I need effectively split my incoming signal." Then you turned into a debate about SNR and not only scared him away from doing something he could have done in a relatively short amount of time, but he now is going to increase his monthly cable bill just so he could have something done that an awful lot of people successfully do every day.

Guaranteed that the installer/tech that goes to add his outlet won't check SNR.


And as I showed you once again in post #12, the OP showed that he didn't know what he was doing.

Only problem is that I don't really know the first thing about what I am trying to do.

I'd like to avoid dealing with having the cable company come out if can. If I can learn something in the process that would be pretty cool too.


Guaranteed that the installer/tech that goes to add his outlet won't check SNR.

Another bet I should put money on. Every Installer I have ever seen has checked SNR of a channel in the 650-750Mhz range for that specific reason.

Put money on it.

Have a nice day, BeachComber.

*wades through the urine*

I ain't skeered! I just have ADD. And I have been very busy. (http://picasaweb.google.com/zachula/KitchenWrapUpAndHomeTheatreStage1#)


I do have a cable modem but its not your average bear. I have a comcast business account for my internet so that I get more bandwidth and a TOS that allows me to run my website and mailserver without violating my terms. Its also in front of my firewall so I am not sure how hard it would be to access its internal stats or if it even has the same functions as the consumer models.

I could always just drag my cablebox around and go into the setup menu on each outlet and check that way.

As much as I would like to DIY, I don't think its in the cards as the learning curve on my scanner really necessitates the need for some hands on personalized training which I wouldn't expect anyone to give me for free and I can't afford professional training from both a financial and chronological sense. Also being that I have a scanner which is EOL'd by the manufacturer and its not exactly something that has enough market penetration that I would find howto's on the interwebs, I would just as soon seek an alternative means to my end that is both economical and functional.

It seemed fate was feeling the same way. I was scanning over my cable bill since they sent out a new rate sheet with my bill this month and I noticed that for .99 a month I can get a service plan which covers my inside wiring. I hopped online and basically laid out verbatim my situation and my plan to one of the comcast reps. I specifically asked if I had to carry the coverage for a minimum period and they told me that once added to the account it can be removed at any time. They were also very adamant that this covers all splitters, drop amps, etc that will be required. So I pay .99 a month for as long as it takes for me to finish my wiring "closet", after which I will hook it all up with whatever splitters I have on hand. When it doesn't work right, I will make the call and hope that I get one of the good techs. I will see if I can't buddy buddy up with them to ensure that it gets handled properly.


So while I appreciate the input and I definitely learned a great deal, ultimately I am going be having the cable company check my inside wiring since its only going to cost me at most 6 bucks(6 mos @.99).

i have decided to take advantage of the cable companies spp which costs a paltry .99 a month. "SPP"?? :confused:

What one of the eariler posters stated, measure the highest analog channel (say 72) near the ground block, use 4db loss per 2 way splitter, add 1-2 db per run for cable loss. I usually try to maintain a anlog signal level of +5dbmV at the set for CATV. No need to go higher.

How many sets (outlets) are you looking to have?
How about OTA? Anything with a outdoor antenna?

I don't trust the C/N ratio readings with these less expensive SLM's anyway.

Bruce,
Part of the problem is I don't know how to operate the measuring equipment. I can push buttons and make things happen but its all greek to me. I picked it up on a whim thinking I could look it up and figure out what I was doing but alas the information just isn't readily available. This could mean several things. Either its so old as to be obsolete and basically useless for this application, is so specialized that you have to have the company come train you on it, or requires a background in Rf and signal engineering.

I suspect its mostly the last one.
I'm not an Rf engineer, and don't want to be one. I prefer SQL and trend analysis.

I don't do OTA as I have digital cable.

As to the design of the network there are 8 drops. Only 5 of them will be in immediate use, one of which will be for my cable modem.

the SPP is a plan which covers the wiring in your home, all splitters and drop amps, plus the technician call out which they normally charge 20 bucks for. I already called the cable company and told them what I plan to do and they didn't have a problem with it and were more than happy to sign me up so I figure there's no ethical issue either. I even asked them if I had to keep the plan for a certain time and they informed me that I didn't.

Basically the problem is this. I am on a tight schedule. I have to get some things buttoned up before thanksgiving because everyone is coming to my house. There is(was) a certain amount of time allotted for this project. Initially it seemed that since I have the stuff I should try and diy since that appeared to be the cheaper and faster alternative. The research took time which meant it was no longer the faster method. When you start adding drop amps to the mix it also ceases to be the cheaper method. Add to it the learning curve involved and well the choice is obvious. Its not that I am giving up or don't care to learn....I'll deal with the signal analyzer another time when I have more of it.

Either its so old as to be obsolete and basically useless for this application, is so specialized that you have to have the company come train you on it, or requires a background in Rf and signal engineering.It's not old, obsolete or useless. It wouldn't be my choice, but it is useful. You don't need anyone coming out to train you. It isn't a $50k Spectrum Analyzer or a Network Analyzer. I'm not an Rf engineer, and don't want to be one. You don't have to be. Not even close. It's not all that complicated. It might look so at the start, but if you tackle one function at a time, it should be easy to master. Most of the problems are the poorly written manuals that are supplied, not the equipment itself. They all have 'quirks', no different than consumer electronics.
You mention SQL and trend analysis. That makes you much smarter than me, which tells me, you shouldn't have a problem here.

Eight outlets will require a distrubution amp. Only one after the ground block (as long as the input signal isn't too high). This is where that meter comes in.

If you don't have the owners manual, here it is in .pdf form;
http://www.protektest.com/ProdManual/Man_3201.pdf

This appears to be more of a general Field Strength Meter than a CATV SLM (Signal Level Meter). More useful for general OTA spectrum scanning, not necessarly TV, but for any RF signals. Unfortunately, it only goes up to 2GHz, so the 2.5GHz WiFi band is out of the question.

Since this isn't a decicated CATV and/or MATV meter, you will have to enter the actual frequency of the TV channel you want to measure. I don't see any pre-defined 'channels'.

Here are channel tables for CATV and OTA;
http://www.n2prise.org/catvfrq1.htm
http://www.n2prise.org/broadchs.htm

From the same source, this might be of help;
http://www.n2prise.org/matvbil1.htm

Not the point. If he cannot lock on and read the S/N on the 256QAM, which is just as important as the signal strength, its not going to do him any good.

You can't usefully measure SNR with a meter when most of the noise is generated within the receiver. Doing so just tells you the quality of the meter's own amp. Signal strength is the figure you need.

Interesting about that analog carrier at the end of the bandwidth... I wondered why my cable company had some weirdo local weather channel way out there, when all the other analogs weere lower down.

Not here.

There may not be programming on that channel, but there is probably a channel there. AGCs need it.

72 is the highest analog channel. Confirmed on a SA.

79 here. The cable systems in this area used to each have one analog channel between 110 and 120 but no longer do. I think they did that just so techs who didn't yet had QAM meters could evaluate signal strength up to the top of the band.

Someone from Comcast said the automatic gain control in the line extender amps used a channel in the low 60s.

You can't usefully measure SNR with a meter when most of the noise is generated within the receiver. Doing so just tells you the quality of the meter's own amp.

Incorrect. It is a useful measurement and anyone that knows digital is aware of this.

Incorrect. It is a useful measurement and anyone that knows digital is aware of this.

Heh. Did you even understand what I posted or did you just go straight for the insult?