Cable Signal Meter Tutor Meter C-100 Field Meter (shown below).

Suppliers: Tektruk – www.tektruk.com Tutor Meters – www.tutormeters.com Amazon – www.amazon.com

1|Page

Cable Signal Meter Televes H30 CATV Meter / Analyzer (shown below).

Suppliers: Televes – www.televes.com

2|Page

Televes Meter –Understanding the Terms Digital Signals Power: is the signal power read in decibels (db) C/N: (Carrier to Noise Ratio) The carrier (signal) to noise ratio is a representation of the carrier quality. A high C/N ratio provides good quality of reception. MER: (Modulation Error Ratio) The Modulation Error Ratio is a representation of the modulation quality. It divides the average power of the ideal modulation to the average error of the actual modulation. If each modulation were completely perfect, the MER would approach infinity. 20 to 45 = good BER: (Bit Error Ratio) If a bit’s modulation is erroneous enough, it can cause a Bit Error. This is a bit that is interpreted incorrectly. The BER is the ratio of erroneous bits compared to the number of bits sent total. The smaller the number, the better. PreBER: the BER before any software error correction takes place. PostBER: the BER after software error correction. This is the most important parameter for troubleshooting as PostBER has the most direct correlation with poor signal reception.

Example: PreBER = 8.1 e – 05 This means 8.1 errors present every 100,000 bits of data BEFORE error correction PostBER = 0.0 e – 05 This means there are 0 errors present every 100,000 bits of data AFTER error correction

E-01 = 10 E-02 = 100 E-03 = 1000 E-04 = 10,000 E-05 = 100,000 E-06 = 1,000,000 E-07 = 10,000,000 E-08 = 100,000,000

3|Page

Testing Signal Strength Matrix Customer Tech Support can supply you with this chart (on next page) to record actual signal readings for each channel. A completed copy can be left with the customer incase follow up is needed with their cable provider. Another copy must be submitted with your dispatch completion. 1. Before you start, start a unit and scroll through each channel and circle the ones on the chart if it is fuzzy or grainy. 2. Go to another unit away from the first unit you tested and do step 1 again. You are checking to see if the “bad” channels are with certain units (could be a tuner or coax issue) or on every unit (could be something with the signal strength coming into the units). 3. Hook up your signal meter to the coax coming into the unit. Scroll through the channels and record the decibel readings on the chart on the next page. a. If the signal is good, test again where the coax hooks into the tuner in the console or external tv. Record on separate chart and label where the reading was taken from. b. If the signal is bad, go back as far as you can on the coax run and test the signal there. Record on separate chart and label where the reading was taken from. c. Remember weak signals can occur just by having 90 degree bends in the coax. Simply straightening the coax to eliminate

Signal (both PCTV and non net capable TV) – Common sources of video signal are cable, satellite, or over‐the‐air antenna systems. These choices will provide signal in analog, digital, or both formats. The Matrix MYE TV will work with both analog and digital signals, but depending on the encryption on the digital signal, a head‐end system may need to be installed. In order to provide high quality images, a signal strength of 10dBmV (+ or – 2dBmV) should be supplied to each screen regardless of whether it is an analog or unencrypted digital signal. If your cable company broadcasts on an encrypted digital signal, a head‐end system consisting of a setup of modulators and combiners that converts the digital signal of different channels into one coaxial cable to run to the TV may be needed. Contact the business division of your local cable provider or contact a local contractor to be certain you understand your signal needs. The cable provider or contractor can assist in setting up a head‐end system.

4|Page

Actual Channel Signal Readings Tuner > Frame > Before Splitter > After Splitter > Wall > Head End > Building Signal strength reading below taken from this location: ________________________________________ Channel 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Reading

Channel 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61

Please circle what is being used: Coax Connectors outside the unit: Screw on Splitters: Taps:

Yes

Yes

Reading

Channel 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91

Reading

Crimp

Compression

Channel 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120

Reading

No

No

Signal boosters/amplifiers:

Yes

No

If splitters are being used, how many are split between 1 wall outlet? ___________ **take pictures of splitters, taps, coax, connectors, etc. and email to Matrix CTS

5|Page

Cabling Terms Cable 

Cable television and Internet systems use RG-6 video cables to transmit high-frequency digital signals from satellite receivers. RG-6 cables designed for cable television and Internet usage have an impedance of 75 Ohm and typically feature copper braiding to prevent stripping, brass or nickel coating to prevent wear-andtear damage from frequent handling, and gold-plated center connector pins for optimal signal transfer.

Decibel (dB, db, DB) Meaning A unit used to express relative difference in power or intensity, usually between two acoustic or electric signals, equal to ten times the common logarithm of the ratio of the two levels.

Attentuator Meaning An attenuator is an electronic device that reduces the power of a signal without appreciably distorting its waveform. An attenuator is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, an attenuator provides loss, or gain less than 1. Taps Meaning 

Coaxial taps are low-loss devices used to feed multiple televisions or decoder set-top boxes in a given space. Common places for coaxial tap use are in schools, businesses, and barracks environments where multiple displays must be fed from a common signal source. The coaxial lead from the source is called the trunk line, screwed to the tap's input where the signal experiences roughly 1 decibel of signal loss. Each television is then connected to the tap. The tap device includes an output leg, leading to another tap and so on. Taps have varied levels of attenuation, with the highest attenuation device installed first, gradually reducing down the chain. Example of use



A tap is used when a cable needs to feed TVs in one location and then continue downstream to more locations. Rows of fitness equipment in gyms are a good example. The cable (called a "trunk" at this point) will hit a tap to feed a block of four rows. The cable connected to the output side of the tap will run down the row to the next row where another tap will be inserted, and so on to the last row. The closest taps have the highest attenuation, while taps at the last row have the lowest attenuation.



Taps are rarely used in homes. Most home systems use a single splitter near the demarc (point at which the cable enters the house) to feed all of the drops.

6|Page

Splitters Meaning



Splitters are considered more of a "dead-end" device , where a single feed from the outside feed is divided a certain number of times. In the above example it would be used at the end of the line to feed the row of units. Unlike a tap, the signal experiences 3.5 decibels of loss. Splitters are usually limited to four outputs to prevent excessive loss. It is important to not "stack" splitters, since this loss is additive. Once a signal loses roughly 12 decibels of signal, very often the decoder or tuner cannot reconstruct the original feed. Effect of splitters



A splitter will cut the signal by 3.5 dB at each output for every doubling of ports. IOW, a two-way will cut 3.5dB. A four-way = -7 dB, and so on. For this reason, a broadband amplifier is used before the input of the splitter to compensate for the splitter insertion loss. Read more: http://www.doityourself.com/forum/home-entertainment-center-tvs-stereos-vcrs-dvds-bluraymedia-players/334706-difference-between-tap-splitter.html#ixzz2yEQrz3jM

Amplified Splitters Meaning 

Amplified splitters are devices that incorporate a built-in booster, using AC power. These devices often have an adjustable potentiometer, allowing the user to raise or lower the amount of signal from the booster as needed. These devices mitigate the effects from multiple splits and longer coaxial cable runs exceeding 200 feet, where losses usually test the limits of the signal.

7|Page

Read this example of a technician running coax cable through a school hallway. Need to know info: A broadband video system is designed by starting at the end of the line and working backwards. Different sizes of cable (RG59, RG6, RG11, etc.) attenuate the signal at different rates. The loss is specified in dB per hundred feet. Installing a tap in the line at any point causes an insertion loss of roughly 1dB between its input and output. Insert ten taps right next to each other and you'll see a difference of 10dB between the input of the first and the output of the last. This has nothing to do with the dB rating of the tap or the number of TV drops on it. (Or whether there are any TVs connected to it.) Input-to-output is simply a pass-through. The ratings of taps range from 3dB to 30dB. This is the attenuation that will be found between the input side of the tap and each port on the tap (plus 1dB insertion loss). In terms of dB, it's simple addition and subtraction. Example of installation: In the example of the school hallway, we're told that we need 12 TVs on three four-port taps, the hallway is 100 feet long, and it's 100 feet from the beginning of the line (the "head end") to the first tap. The cable loss is 6dB per 100 feet. Each TV needs a signal of +9dB, but we'll ignore that for now. 200 feet of cable = 12dB loss. Three taps = 3dB loss. There will be a total loss of 15dB at the end of the line. The smallest 4-port tap available is a 7dB, so we need to have a total of +22dB at the head end to overcome all of the losses at the end of the line. This is accomplished by inserting an amplifier at the head end with enough power to make up the difference: +22dB. Now that the EOL is done, we work backwards to determine the ratings of the taps at 150 and 100 feet. At 150 feet, we have a difference of one splitter and 50 feet of cable = 4dB less attenuation. We need a bigger tap value to match the tap at the EOL. 4dB + the EOL tap of 7dB = 11dB. At 100 feet we have a difference of two splitters (2dB) and 100 feet of cable (6dB) = 8dB. 8dB + the 7db tap at EOL equals 15dB. Our choices for tap ratings are 14dB or 17dB. 14 is closer. To this point we haven't addressed the +9dB we need at each TV. All we've done is balance the system for the insertion losses. At this point it's a simple matter of increasing the signal by 9dB at the input or the output of the amp (or both). One more thing before I close this book: Cable loss specs include the frequencies at which the attenuation is specified. This is because the signal is attenuated more at high frequencies than it is at low frequencies. To make up for this lop-sided loss, most amplifiers have a "slope" control which equalizes the signal. Calculating slope over distance gets a bit more complicated, but uses the same methods. Read more: http://www.doityourself.com/forum/home-entertainment-center-tvs-stereos-vcrs-dvds-bluray-mediaplayers/334706-difference-between-tap-splitter.html#ixzz2yERcobYx

8|Page