Coaxial Cabling (75 Ohm Broadband) - Acceptance Test

What it is

This form is the acceptance record of 75 ohm broadband coaxial cabling - Series 6, Series 11, trunk, feeder or distribution cable, braided multipurpose cable and cords - in a star installation or a bus backbone with star horizontal, for CATV, satellite and similar services, one installation and up to six runs per record. It follows the two site visits TIA 568.4-E describes: visual inspection and verification of every run at rough-in, then qualification or performance characterization at trim-out. Insertion loss and return loss are graded for non-plenum Series 6 and Series 11 only; other cable is recorded against the manufacturer data. Terminations, outdoor sealing, bus termination and the residential outlet run are also graded. Twisted-pair and optical fiber links are recorded on the low-voltage, low-energy cable acceptance form.

Why it is performed

A broadband coaxial run carries video, data or satellite signals whose quality depends on an unbroken center conductor and shield, a matched 75 ohm path from end to end, and connectors that were made up correctly. A kink, a staple or a crushed jacket at rough-in degrades the run before anyone has watched a picture on it, and after the walls close it cannot be seen again; an open, a short, a poorly made connector or an unterminated bus end shows up only on an instrument. Inspecting and verifying every run before sheathing, then sweeping or qualifying it at trim-out, catches both kinds of defect while they can still be corrected, and the record keeps the instrument, its calibration date and the trace reference with each reading so the result can be reviewed later.

When it is performed

Visual inspection and verification belong at rough-in, after the cable is pulled and dressed and before insulation and wall sheathing go in; a record made after sheathing is raised as an issue for review, not a fail. Qualification or performance characterization follows at trim-out, once the final connectors, terminators and outdoor seals are in place. The two visits are entered on one record, each with its date, and the record reads incomplete until the rough-in visual items and timing, every used run's verification, and the trim-out result are all recorded. No recurring interval is part of this form.

How it is typically performed

Identification records the project, building, area, installing contractor, building type, plant type, topology, the technician, the test instrument with its serial number and current calibration date, and the design documents. Each used run is entered with its identifier, subsystem, cable series, shield, plenum rating, service band (CATV to 1002 MHz or satellite to 3000 MHz), length, environment, the connector at the cross-connect and at the outlet, outdoor sealing, F connector type and any intermediate point. At rough-in the visual checklist is marked for all runs together - no damage from nails, staples, kinks or tears, separation from EMI sources as designed, bend radius at least 10 times the outside diameter (20 times under pulling load) or the manufacturer value, no excess length or slack loops, connectors properly terminated, bonding and grounding at the demarcation point, and unused energized ports terminated in 75 ohm - and every run is verified end to end for continuity with no open and no short, outside plant runs on both the center conductor and the shield. At trim-out the method is chosen: performance characterization, the recommended path, sweeps each run from 5 MHz or lower to the top of its service band and records the worst-margin insertion loss and return loss with their frequencies and the trace reference, the form computing the TIA 568.4-E limit and margin for each; qualification uses live service signals or a qualification instrument judged against the service provider's specification, with the received signal level and provider minimum recorded. A bus backbone records its end termination. The record closes with who tested, when, the labeling scheme, the provider specification and the manufacturer data it relies on, and the ambient temperature.

What gets recorded

Identification: project, building, area or floor, installing contractor, building type, plant type, topology, technician, instrument make, model, serial number and calibration date, design documents. Per run: identifier, subsystem, cable series, shield, plenum rating, service band, length, environment, cross-connect and outlet connectors, outdoor sealing, F connector type, intermediate point, and the computed length, residential, termination, sealing and intermediate-point checks. Rough-in: the seven visual items as satisfactory, unsatisfactory or not applicable, inspection date, timing relative to sheathing, and each run's verification result. Trim-out: date, method, qualification source, method and result, received signal level, provider minimum and specification reference; per characterized run the sweep start and stop, insertion loss frequency, reading, limit and margin, return loss frequency, reading, limit and margin, and the trace or export reference. Bus backbone end termination. Tested by, test date, labeling scheme, provider specification and manufacturer data references, ambient temperature, comments and deficiencies.

How results are evaluated

The verdict combines graded rules with completeness gates. Graded: on a non-plenum Series 6 or Series 11 run the insertion loss at its worst-margin frequency inside the service band must not exceed the TIA 568.4-E limit for the series and subsystem (fixed for the row whatever the length, stated at 20 C, never below 3 dB in the field, shown rounded down so a reading equal to it passes), and the return loss must be at least 20 dB from 5 to 1002 MHz and at least 15 dB above 1002 MHz up to 3000 MHz on satellite service, a CATV reading above 1002 MHz not being graded; no run shows an open or a short; no visual inspection item is unsatisfactory; every termination conforms (F-type male at the cross-connect, F-type male mated to an F-type female feed-through at the outlet, a 75 ohm BNC at a cross-connect outside residential buildings only, 5/8-24 male on trunk, feeder or distribution cable) and outdoor connectors are sealed; a residential outlet run is Series 6 or Series 11 and 90 m or shorter; a bus backbone ends in a 75 ohm termination or a matching last device; and where qualification is the method, a result the technician records as not acceptable fails the record, an UltraDb convention since the standard sets no level. Incomplete, not failed: run attributes or topology unrecorded, a visual item or the timing blank, a used run left untested, no trim-out result, or a sweep that stops short of the service band. Issues only: the advisory run lengths, a consolidation or horizontal connection point in a run, a rough-in record made after sheathing, a blank calibration date, and a signal level below the provider minimum. Other cable series, shield construction, F connector type and the ambient temperature are recorded, never graded.