DOCSIS Archives

22 02, 2023

Are Staples in Coax Cable Impacting My DOCSIS speed?

Mia Colabrese2023-02-22T17:43:08-05:00February 22nd, 2023|

I recently posted a YouTube short (https://www.youtube.com/shorts/n5ucjCb-iGA). ) about how staples in coaxial cable can cause micro-reflections and interfere with subscriber modems. The video was well-received, and I received a lot of feedback, including real-world experiences and questions about the implications of these issues. Let’s take a closer look at this subject. Staples in coax cable meets the real world Let’s start off with an example of real-world feedback I received. The example goes as follows: “I’ve had calls for this. Poor US voice quality. My worst

29 01, 2023

What is a dB?

Mia Colabrese2023-05-01T16:12:26-04:00January 29th, 2023|

What is a dB? RF and Cable Basics :: Brady Volpe and Ron Hranac discuss RF and cable basics in a new series designed to help those who are interested in understanding RF and Cable TV technology a little better. In this first episode we cover what is a decibel (dB). This is a fundamental unit of measure that every person working in the cable industry should understand. To learn more, watch this episode 0:00 Intro 4:30 The Decibel Primer Beginning 5:13 What is a Logarithm 9:15 Question

7 09, 2022

Got a DBC to Change Your Cable Modem’s OUDP IUC? I thought so.

Mia Colabrese2022-09-07T14:31:24-04:00September 7th, 2022|

What is a cable modem’s OUDP? What’s an IUC? What’s a DBC? If you already know these initialisms that is awesome. If you don’t, that is fine too. DOCSIS 3.1 introduced OFDMA for more efficient upstream data transfer. In this article, I’ll cover how an impairment will cause the CMTS to change a single CM’s OUDP IUC using a DBC transaction. I will also hopefully help you understand what the heck I just said.What are cable modem profiles?Let us start the discussion with orthogonal frequency division multiple access

6 06, 2022

OFDMA — It’s Trending

Mia Colabrese2022-06-06T09:14:00-04:00June 6th, 2022|

OFDMA — It’s Trending What’s trending in cable? It’s OFDMA or orthogonal frequency division multiple access. OFDMA is the upstream counterpart to OFDM, which stands for orthogonal frequency division multiplexing. Both are part of the DOCSIS 3.1 specification and are intended to increase speed over the DOCSIS network far beyond what can be achieved using legacy SC-QAM channels. Most cable operators deployed OFDM first because the downstream had already reached data capacity limits. OFDM enabled expanded data capacity without node splits. Now that OFDM has been successfully deployed,

22 02, 2022

DOCSIS 3.1 Cable Modem Transmit Power

Mia Colabrese2022-06-06T08:57:26-04:00February 22nd, 2022|

A cable modem’s transmit power is extremely important. It not only determines if the cable modem will be able to come online and register with the CMTS (cable modem termination system) but obtaining the optimal transmit power will make or break the subscriber’s quality of experience (QoE). A DOCSIS 3.1 cable modem’s transmit power introduces some new considerations which are discussed in this article. Why is DOCSIS 3.1 cable modem transmit power important? Transmit power per channel is defined as the average RF (radio frequency) power in the

15 07, 2021

DOCSIS Primary Channel Impaired Downstream Troubleshooting

Mia Colabrese2023-02-17T18:41:43-05:00July 15th, 2021|

In this episode Brady and John discuss what happens to an impaired DOCSIS Primary channel & ANGA COM highlights. When an impaired DOCSIS Primary channel occurs, do to one ore more impairment, how does it impact other DOCSIS channels? Primary being a type of "management" SC-QAM channel. Does it make a difference? We also cover the top content from the ANGA COM show. Didn't have time to watch all of the ANGA COM show material. No problem. Brady and John will make sure your up to speed

2 04, 2021

The Road to DOCSIS 4.0

Mia Colabrese2021-08-15T11:49:09-04:00April 2nd, 2021|

The Road to DOCSIS 4.0. Another power hour of cable with Brady Volpe and John Downey CMTS Technical Leader at Cisco and special guest Jeff Finkelstein Executive Director of Advanced Technology of COX Communications. How to go from sub-split, to targeted mid-split or high-split, then finally to ultra-high-split and 1.8 GHz. Ask any questions you may have in our live chat. The discussion is on all things DOCSIS 4.0. The Road to DOCSIS 4.0: General intro General overview of the history of DOCSIS and the road to DOCSIS

3 03, 2021

Easy Transmission Line Theory

Mia Colabrese2021-03-03T10:27:53-05:00March 3rd, 2021|

A Lesson on Transmission Line Theory Transmission line theory can be intimidating, because of the complex mathematics involved. But I’m not going there. Transmission line theory is further complicated by modeling, say, coaxial cable (a transmission line) as a distributed circuit model, comprising series inductance, shunt capacitance, series resistance, and shunt conductance. But I’m not going there, either. Instead, I’m going to provide an analogy using a bucket of water and hose. Understanding the basic principles of transmission line theory is key to understanding how RF signals transporting

9 02, 2021

NanoVNA testing Taps, Coax, passives and more part two

Mia Colabrese2021-08-15T16:11:56-04:00February 9th, 2021|

Another power hour of cable with Brady Volpe and John Downey CMTS Technical Leader at Cisco, show real world examples of testing Coax, Taps and other passives. The discussion is on all things DOCSIS. NanoVNA (Vector Network Analyzer) testing: General intro Test equipment RF basics Test One Diplex filter explained active equipment has a diplex filter It enables the plant to be upstream and downstream capable 75 Ohm world Cross over Cold solder joints, fingers touching surface mount components issues with diplex filters The higher the split

27 01, 2021

NanoVNA testing Taps, Coax, passives and more part one

Mia Colabrese2021-08-15T16:12:51-04:00January 27th, 2021|

Another power hour of cable with Brady Volpe and John Downey CMTS Technical Leader at Cisco, show real world examples of testing Coax, Taps and other passives. The discussion is on all things DOCSIS. NanoVNA (Vector Network Analyzer) testing: General intro Test equipment Test for bad cable, passives and amps Test return loss, insertion loss, etc Why is it important to terminate Question of event error log Loss connectors impact return loss nanoVNA and VNA explained MainLine Tap You can see the entire cable spectrum Return Loss