Return Loss Archives |

Scalar Measurements with a Broadband Noise Generator

By H. Mark Bowers — Broadband noise generators offer a viable alternative to the tracking generator approach. A fairly flat RF output response noise generator can be purchased for several hundred dollars and can be paired with most spectrum analyzers.

FCC Proof-of-Performance Rules Revisited

By H. Mark Bowers — Revisions to FCC Part 76 Rules were released in April of this year. Significant changes were included in this release, including the rewording of some test procedures and standards, QAM carrier limits for aeronautical frequency notification.

Basic HFC AC Design (Part Two)

By H. Mark Bowers — Preparation for AC design calculations requires a diagram of all amplifiers (system actives) in a tree-branch configuration as was shown in Part One of this series

Basic HFC AC Design (Part One)

By H. Mark Bowers — Many technicians struggle with AC design, particularly in the area of proper power supply placement and loading. AC design involves concepts and principles that we don’t use in every day system maintenance or operation.

Signal Leakage Patrolling at 700 MHz (Part Two)

By H. Mark Bowers — I believe this exercise raises the issue of how one is to perform accurate field strength measurements at higher LTE frequencies, where there is a low-level leak from the HFC plant (especially QAM).

Signal Leakage Patrolling at 700 MHz (PART ONE)

By H. Mark Bowers – Newer leakage detection systems are now available that measure at dual frequencies. While {the} present FCC required leakage detection frequency range remains in the 108 MHz to 137 MHz aeronautical band, measurements at higher frequencies can be revealing and may eventually be required

Scalar Testing (Part Two)

By H. Mark Bowers – In my last column we examined the importance of scalar testing, definitions of various terms, equipment required, and examined waveforms of actual insertion loss and isolation measurements using a spectrum analyzer and tracking generator.

Scalar Testing (Part ONE)

By H. Mark Bowers – In my last column we examined digital QAM testing requirements under present FCC Part 76 Rules and ANSI/SCTE 40 2003 Requirements. In this column we’ll begin an examination of scalar testing and why it’s important in the HFC network.

Return Loss

By Ron Hranac – The coaxial cable portion of our networks has long been designed and built to have a nominal impedance of 75 ohms. The word “nominal” is used to describe the impedance, because it’s pretty much impossible for the impedance to be exactly 75 ohms, especially across a wide frequency range.