How to test spools with a Term Cap™ installed

 

A Term Cap provides a 50 Ohm termination at the far end of your spool of cable. The Term Cap allows you to test the spool of cable at any time using Distance To Fault (DTF) measurements. 

 

A push-on test connector is available for the beginning of the spool or you may install a connector. 

 

Configure your instrument for a DTF Return Loss measurement. It is suggested to use a wide span of 100 to 1000 MHz for LMR and 1001 sweep points (551 minimum). For other uses a span of ~1 GHz centered in your operating frequency range is appropriate. This provides a good trade off of sweep speed vs. distance resolution. Setup the cable type in the instrument. Make sure you check that the instrument configuration supports the required length of the cable you are testing. Once configured perform a user calibration using an Open-Short-Load calibration kit. 

 

The Term Cap will show up as a 15 to 30 dB return loss at the end of the cable allowing you to check the length. Other than the connector at the beginning there should be no responses above 34 dB anywhere along the length of the cable. If there is a response of this magnitude it should be investigated. Otherwise the cable is good to install. 

 

The cable can be retested once installed, while cable hangers are tightened, or during ground clamp installation. Once all is good cut the cable to length and install a connector.

 

Please note that the term cap is a one use device. It is not intended to be removed from the cable and reused.