Q:	I work mostly with coax cable, and I find it difficult to make a solid connection between the alligator clips and the coax connector. How should I do it?
A:	JTE offers several accessory adapters for your ShortStop™ Cable Fault Finder. The list currently includes BNC to "F", BNC to banana plug, and BNC to Telco. You can purchase these accessories directly from JTE, or from any of our distributors.
Q:	Why does the length reading sometimes change a small amount when I open and short the far end of a test cable?
A:	There are two causes. The first is that this is a characteristic of the measurement technique used in almost all low and medium cost cable length test tools. In the case of the ShortStop™ Cable Fault Finder, the variance occurs in only a few cable types and both readings are within the specified accuracy of the instrument. The second cause occurs when the cable is coiled, as in a box or on a spool. The magnetic field caused by the TDR signal itself couples across to other parts of the cable and changes the characteristics of the reflection such that the displayed length is different than the actual cable length.
Q:	When I trace a cable using a tone receiver, the tone that I hear from the receiver is sometimes different from the tone I heard in my previous trace. Why is that happening?
A:	This is the positive cable pair identification feature we call PowerTone™. When ever the cable pair is momentarily shorted, the characteristics of the tone that ShortStop injects into the cable is changed. This change occurs whether or not you are listening to the tone. You can verify, and thus positively identify, that you have located the correct wire pair by momentarily shorting the wire pair and noticing that the tone characteristics have changed. ShortStop uses 5 distinct tones to insure that there is no doubt that you are using the correct wires.
Q:	Does it matter which clip lead I connect to which wire in a two wire test cable?
A:	No.
Q:	Why is it that when I connect only the red lead to a cable, the unit reads a small number of feet, regardless of the actual length of the cable?
A:	The unit's TDR technology requires both leads to be connected to the wire pair or cable in order to determine its length. While using only one of the leads is useful in tracing cable position with the injected tone feature, both leads are required to make length measurements.
Q:	How do I know if moisture in the unit is affecting the operation?
A:	If the unit passes its self test, AND it reads "0" with no cable connected, then the internal moisture is not seriously affecting the testing operation. Some length measurements on cables may be inaccurate until the unit has dried sufficiently.
Q:	How do I calibrate or perform a self test of the functionality of the unit?
A:	There are no adjustments in the unit, and the internal coating protects the critical components from moisture and contaminants. There is nothing to calibrate. Self test is performed by the unit every time you turn it on. Since there is no loss of any settings when the unit is off, there is no penalty to just turning it off and on if you wish to perform a self test.
Q:	I tested an orange outdoor 25 foot extension cord and the display read 19 feet. Is the unit broken?
A:	No. The accuracy of the reading is dependent on the setting of the VOP. The nominal setting is "-66-", but the VOP for that kind of cable is "-56-". To improve the accuracy of length measurements for that or any cable, change the VOP as shown in the instructions. For a complete definition for VOP and a table of most common VOPs click here
Q:	Why, on some long cables, does the number displayed on the readout jump between 2 or 3 different values?
A:	As the TDR signal travels down a long cable, it looses some of its strength. At some point, the noise on the cable has an amplitude similar to the reduced strength TDR signal and will influence the measurement results. The unit's software filters out many of the noise related variations in the displayed length value, but some variations do get through.
Q:	The unit occasionally reads "Err". This message is not explained in the manual. What does it mean?
A:	After we changed the display message for error conditions, a few hundred units were sold with old manuals that did not reflect this change. The messages for "ERROR", "TOO LONG", and "LOAD" are replaced by the message "Err". The most common reason for getting the "Err" message is that there is a device of some sort connected to the cable pair that you are testing. The device, such as a light bulb, transformer, terminating resistor, speaker, etc. absorbs the TDR signal, preventing a valid measurement from occurring.