Q: What does NVP mean?
A: NVP means nominal velocity of propagation. This is the speed at which a signal moves through a cable, expressed as a percentage of the speed of light in a vacuum. We use this speed, along with the time it takes for a signal to return to the testing device, to calculate cable lengths.
Q: I have one of your cable tools and I need to measure different cables of various thickness's or NVP. The cable type in the library doesn't offer me all cables I want, can I add my own cable to the library and if so how?
A: Custom Cable Setup is used to measure and store the NVP of a cable of a known length. Connect the Cable Tool to a piece of cable that is between 50 and 100 feet long and is open at the far end. (Cables less than 50 feet or longer than 100 feet may not give accurate NVP results.) Turn unit on and Select F3 - Tone then select F3 again to get into Setup.Press the Down cursor key 4 time to select CSTM Cable by pressing F3. Press the Up/Down cursor key to select one of the four Custom Cable storage locations. Press the Select function key to advance the arrow to the length field and then use the Up/Down cursor key to adjust the displayed cable length until it matches the known length. The NVP changes as the displayed cable length is adjusted. Press the Save function key to store the information.
Q: In the 'custom cable mode' set up, can I connect a small (3 foot) section of cable of the same type I want to test, and have the CT-50 memorize the type and NVP value for that cable?
A:We recommend a cable length of 50 feet. Lengths greater than 100 feet will have skewed NVP accuracy. Shorter lengths can result in measurement errors because of cable length versus wavelength limitations.
Q: I want to measure wire left on a spool or in a box, Can the cable tool measure just one conductor (single core wire) or are we require to have 2 conductors for every test?
A: The Cable Tool (CT50) is a multi-conductor TDR which means there needs to be two conductive paths (wires/cables) in close, consistent proximity to each other. A good example would be lamp cord, coax cable or network cable (Cat 3, 5 or 6). The Cable Tool will not work on a single conductor. The Cable Tool leads (red and black) should not attached to the same conductor (wire/cable). They need to be attached to different conductors (wire/cable). A common mistake in the physical setup of the CT50 is connecting one end of the cable to the black lead and the other end of the same cable to the red lead. The user guide says "Clip one test lead to each of the two conductors of the cable to be tested." Example: A single strand 10 gauge wire on a spool or laid out cannot be measured. Two strands of 10 gauge wire twisted around each other could be measured. If one end was shorted together. The reading would be SHORT, XX FEET. If the end was open, the reading would be OPEN, XX FEET.
Q: Do you have a complete list of the cable types stored in the CT-50 pre-stored library?
A: Yes, the Cable list is located under the Cable Tool's Document tab on our website. Here is the direct link: www.psiber.com/en/home/products/cable-tester/cable-tool.html
Q: Will the Cable Tool CT-50 measure cable that is 600-700 MCM?
A: MCM cable is a single conductor cable. So if the cable is on a spool the Cable Tool would not be able to measure the length. However, if the cable is in a conduit with other MCM cables then the Cable Tool would be able to measure the length to a short or open between these 2 cables.
Q: Can you advise how to use the Cable Tool to work with Cat5 cable? Is there an RJ45 adapter available?
A: If your Cat 5 Cable is terminated with a RJ45 connector, we do not offer an adapter. A commercially available "Banjo" adapter can be used with the Cable Tool. You could create one by using a thru connector and another RJ45 with short conductors protruding from the one end or you will have to cut off the RJ45 connector and expose the individual conductors.
Q: Does the CT-50 require any annual calibrations?
A: No, the Cable Tool does not need to be calibrated. We calibrate the Cable Tool once while in production before it goes out to customers.
Q: Can the CT-50 recognize fluid impregnation of the cable under test (where the resistance changes but does not reflect an open)?
A: The Cable Tool looks for hard opens and hard shorts. This means that the open or shorted cable thresholds are about 10 times that of a normal cable impedance. For example, if your cable impedance is 100 ohms then a hard short would be about 10 ohms or less. A hard open would be 1000 ohms or more. Fluid, like water, will make a high impedance short which would be greater than the threshold for the Cable Tool. For this type of measurement a graphical TDR would be needed.
Q: Can the Cable Tool CT50 measure more than 7500 feet?
A: The Cable Tool will measure cables out to 2500 feet.
Q: What is the accuracy when identifying an open or short on a twisted pair, using the pre-stored NVP values?
A: Using TDR technology, the Cable Tool diagnoses cable faults with no launch or dead zone and an accuracy to ±2% ± 2ft ±NVP error . For example, a 200 ft cable would show between a 194-208 measurement.
Q: The CT50 will be used where adjacent cables would be energized and or carrying data. Will this affect the accuracy or the ability of your CT-50 to perform as designed?
A: This might make the length reading noisy or jump around a little bit. The amount of noise in the length measurement will be different for each situation.