If you folks do cable televison installations, how do you check if the connection was made correctly? I wish I didn't have to do cable/ telephone installs but because of the money I know why my company does them. We have to carry around a customers television when necessary to test the signal. Is there a special tool that can do this? And if so, what do you use?
--Ron
We use the Leader TV Signal Level Meter Mod#LF 941 it's about the lowest priced one out there to do the job right, I think we paid $790.00 for it and we pay $160 a year for calbration, Input 75 ohm 110db uv max, 50dbmv max.
Assuming you have an incoming signal already on line from the cable company -small portable color tv set(mine is from Sam's Club $145.00. ).
I thought he was asking for the proper equipment to use, the cable connection is used for more then TV reception, the TV may work fine, then when other services are connected, it fails, what we usually find is the shield is not making good contact, or the cable has kinks in it, the TV will still give a good picture, but other services may not work.
[This message has been edited by LK (edited 11-13-2005).]
LK, I did a search for the product you listed. Is this what you have:
http://www.testequipmentdepot.com/leader/lf941d.htm ? It just seems what with all cable tv wires are used for these days (internet, tv, phone lines, etc), that a tool for measuring cable signals would be something good to have. I didn't realize it was so expensive though.
Ron,
This sort of test equipment has never been cheap.
It does pay to have the proper gear though.
Ya, just one of many pieces of test equipment, There are less expensive testers, that may work well, your main concern will be clean signal, and band width, now you know why some of the electronic techs charge up to $190 an hour, they have the expensive tools, if you are doing a lot of communications wiring it may just pay, otherwise, use the TV and hope for the best, i would say 90% of the installations are not tested, they use the install and hope system, hope it works.
[This message has been edited by LK (edited 11-13-2005).]
Well I know I talked about this subject before here someplace- damned if I can find it.
Short answer is if you call it a "tester" and expect it to work like a Wiggy there ain't no such thing.
What you need is a signal level meter. It does take some interpretation as well as knowledge of CATV to be able to use it. They don't come cheap and unless you are willing to learn a new trade and have someone to teach you I recommend that you not waste your money.
In my opinion you would be beter served just to install the cables and leave everything else for the cable guy.
-Hal
Not to sound negitive, but...... why test it?
It's a simple termination. I've never been called back because a Cable term failed.
If you want to buy a new tester for $750 there are a lot of other meters I'd buy first.
JMHO
Rob
Original question - quote "If you folks do cable televison installations, how do you check if the connection was made correctly?"
Lk, I answered for the question, which was television installations, not cctv,broadband internet connections, Universal Studios film lot #3, or mission control at Houston. My answer is a simple one for TV on a new residential job that you don't want to have to come back to. If the new owners call in for Road Runner, and the cable connections I have made are inadequate, then the cable guy can fix it himself with his fancy "testing meters". By the way I use a Cable Pro 360 for my inside connections, which gives a far superior connection to even snap and seal connectors for interior connections. Nobody ever has complained to me to come back to fix anything I have done on a cable tv system. Now if you want to spend thousands on equipment you don't really need to get the job done, may I suggest the new Greenlee speed bender line for your next job running 1/2" emt.
Here is my two cents worth. Invest in a good crimper, stripper, and learn how to use them correctly. In addition use quality hardware, connectors, and cable.
Using good tools helps, the connection is not the only concern, cable kinks, and length of cable are usually the problems we find in bad installs, one reason they don't call back may be they were not satified with a failed cable, about half of our repair work is from poor cable installs, in this area if it is interior wiring, the cable company charges for repair work, many times the TV reception was fine, then they signed up for cable modem, or added Digital Sat TV then the problems appeared, as Hal noted, there is more involved then just running a cable, and crimping a few connector on.
We value our customers, and would not think of letting the cable guy fix a problem that can be avoided with good testing, installations may differ, depending on the area and services offered, here multi services are offered on cable, including phone services, one good reason for testing, is they just may be using digital phone service, and a missed 911 call, or they have their security services monitored by cable, it can be a real disaster.
[This message has been edited by LK (edited 11-14-2005).]
When I worked with LP UHF & MMDS transmitters, we would actually use spectrum analyzers with tracking generators to check our cables. Depending on the application, RF power meters and directional couplers too. It can get pretty elaborate and cost prohibitive. I wonder if any folks doing this kind of work might have access to a frequency agile RF modulator? Not out of the question with home theater systems these days. If you do, that and a wide band power meter would give you the means of doing the equiv. of a 3 step(or more) slope test. You would just have to observe the flatness of the output of the modulator according to the meter before inserting the installation cabling into the path. I was looking at some of your posts about the various power meters. What do you do if the signal (cable?) isn't available yet? Do some of these meters also generate a signal that you can inject? Just curious.
Joe
I never found out, but our cable TV provider has some type of signal meter that shows up on our screen near channel 98 or something like that. Does anyone know what that is for, and does it offer any signal description?
"What do you do if the signal (cable?) isn't available yet? Do some of these meters also generate a signal that you can inject? Just curious.
Joe"
What we have is a portable dish on a stand, just takes a few minutes to point, an there is our test signal, it is the digital switches, that present a problem when testing, best to have all the equipment in place, then do your testing, cable on steriods, has presented a real chalange for installers.
Ron,
They ping out a signal for their installers to use for signal level, when they do the install, this is a general test, and a pretty good indication of reception.
[This message has been edited by LK (edited 11-14-2005).]
Ok, now this is getting ridiculous.
Some of you may know that we used to do a lot of work for the cable companies, both outside plant and multiple dwelling units. We usually designed everything we did. Before that I had a large MATV company that did pretty much the same thing with off-air TV and multiple dwelling units like apartment buildings and condos. So I should know what I'm talking about.
To answer your question, no, a signal level meter does not provide it's own signal. You have to be connected to the cable system in order to use it and you also have to have the distribution such as splitters complete but that's not your job so that should end the arguement right there.
But then we have LK who evidently carries a dish and receiver around with him. Trying to figure that one out. I thought we were talking about CATV? Are you in the sat business?
Joe, cable systems have "sweep" systems in place to maintain the system levels. They operate transparently to normal TV reception and use receivers that have a display similar to a spectrum analyzer. The sweep is only used for trunk and feeder adjustment and maintenance, never for non-critical stuff like drops and building distribution. Just not necessary.
We value our customers, and would not think of letting the cable guy fix a problem that can be avoided with good testing, installations may differ, depending on the area and services offered, here multi services are offered on cable, including phone services, one good reason for testing, is they just may be using digital phone service, and a missed 911 call, or they have their security services monitored by cable, it can be a real disaster.
Again, unless you are an experienced CATV or sat system installer and have the knowledge to design and test your work you have no business doing anything other than running cables.
-Hal
AFIAIK, that CH98 thing is a return channel monitor (usually a spectrum analyzer), so a field tech can instantly see the signal going back.
Hal,
The old analog systems are long gone, everyone is going digital, the post was " If you folks do cable televison installations, how do you check if the connection was made correctly?"
With cable service suppliers going digital, they are offering more services today, then just TV, with that said inside cable wiring is more critical then it was in the past days of analog signals.
LK,
You've got me a little confuzzed here. Are you saying that you connect the LNB at a cable entrance and a receiver at the far end? If so, that would verify the DC path for LNB power and polarization, perhaps 25Hz for any switch, and bandpass from 950-1450MHz. It wouldn't verify any of the VHF or cable bands. If you use the RF output of the receiver, you're probably just checking channel 3 or 4.
Hal,
Is the signal level meter that you describe one with a tunable, perhaps 6MHz 3dB BW? I don't think it is unreasonable to want to have a way of testing your work without relying on cable company equipment or personnel. If for no other reason, they might not even be in a new developement while cable is getting roughed in. I would think that companies that manufacture high quality level meters would also produce signal generators that cover the cable spectrum to partner with them.
Joe
Joe,
We ping a broadband transponder, then use our digital receiver, for signal injection, we can also generate just about any signal we need, on the other end is the Leader signal equipment or RF Analyzer, the analyzer is a bit pricy for most, a $2,000 piece of equipment is not for everyone, ours goes from 100khz to 2.06 GHz. very nice display, and plenty of presets.
Spent a lot of time in the communications field, everything from shore stations to ground stations, now i spend lot of time on the low bands, still enjoy the cw chat, but the HF guys are out there doing some wild things these days.
WB2OMS
Les
[This message has been edited by LK (edited 11-15-2005).]
With cable service suppliers going digital, they are offering more services today, then just TV, with that said inside cable wiring is more critical then it was in the past days of analog signals.
Actually it's not. All you are talking about is one cable modem and that should get connected before any distribution where the service enters the premises, and that either works or it doesn't with a wide latitude unlike an analog TV receiver.
For Joe and LK- again that's not our job! Matter of fact the state of Connecticuit has separate licensing for cable TV and MATV installers and techs. It's not even part of the electrical board of licensing and if you want to do this kind of work, whether you are an electrician or not you have to pass that test and obtain that license.
I believe the reason for this is because Connecticuit recognizes the fact that this is an area that requires specific training and experience beyond what would normally be expected of the electrical or any other trade that may be interested in doing this kind of work.
I can understand everybody wanting to get into this area but for most that means no better than a DIY job. If you want to take care of your customers do them a favor and either learn the trade or leave it to someone who has.
-Hal
My brother's house has 3, yes, three digital devices, 2 digital cable boxes and 1 modem.
The digital cable boxes function very much like a cable modem with a return band below 50MHz and QAM modulation for the downstream channel. (In fact, you'll find that as the cable modem boots up, it stops on all of the digital cable data carriers, checking to see if they're the downstream for the cable modem).
Problems which affect the cable modem WILL affect the digital cable boxes.
I see people like to use the "digital" catch phrase. Truth is that cable you screw onto the back of that digital cable box and modem is analog RF and probably half of the cable channels are not digital at all. Nothing is new or more critical here except that there is a return carrier that must be taken into consideration.
You will find that the digital channels are actually much more forgiving of things like low signal levels, reflections and interference due to the method of encoding. As signal levels are reduced you won't get snow but beyond a certain point the picture gets pixilated then nothing.
I dare say that if it seems like there are more problems it's because more people rely on cable now and for more than just their expensive TVs. Everybody thinks they are a cable installation expert and that's where the problems come from. Doesn't matter what test equipment you have or what cable and connectors you use if you don't know what you are doing to begin with.
-Hal
[This message has been edited by hbiss (edited 11-15-2005).]
Yes, the return carrier must be taken into consideration.
Problems with the return carrier, which are mostly caused by ingress from poor installations, can be very difficult to track down, especially if they are intermittent.
I recall reading about one case where there were intermittent outages caused by upstream interference strong enough to clip the upstream laser; they eventually tracked this down to a poor installation picking up interference from a nearby ham radio operator. (Legally, the ham radio operator was not responsible for the interference).
At one point, some cable companies had a policy to install high-pass filters (which filter out frequencies below 50MHz) on drops of customers who were not using any services which require the return band. Perhaps some still do, but in this day and age where people want to buy the cable modem at Best Buy and plug it in and have it work that day, probably not.
One of the big problems with troubleshooting digital is that it's "all or nothing", wheras with analog you can tell from the picture whether there's a problem and how much of a problem it is.
Case in point: If I have an analog TV connected to cable and it's on channel 18, I can tell from looking at the picture whether there's an ingress problem. Why? Because pagers operate in the same frequency band and will result in an intermittent herringbone pattern (when the paging tower transmits).
Try doing THAT with a digital cable box with a digital carrier on channel 18.
(One could, I suppose, make the argument that such ingress will not cause problems with the cable signal on channel 18, but that would be a case of not seeing the forest for the trees; ingress which is visible on channel 18 is indicative of a problem with the installation that could affect any channel or any service at any time depending on what signals happen to get inside the cable by the same fault that allows the pager signals to get into the cable)
[This message has been edited by brianl703 (edited 11-15-2005).]
[This message has been edited by brianl703 (edited 11-15-2005).]
Here is a URL that might be useful:
http://www.ct-magazine.com/archives/ct/1099/ct1099j.htm http://www.ct-magazine.com has quite a few articles about the technical side of cable TV.
Brian, thank's for the tip on that magazine. I just signed up for a subscription.
-Hal