Volpe Firm | Technology Blog

4 06, 2021

Machine Learning and PNM

Mia Colabrese2021-08-13T08:43:30-04:00June 4th, 2021|

Machine Learning and PNM Yes, it’s real and yes, it’s deployed and working! The day has arrived, Skynet is here! [1]. Fortunately, no to Skynet and in more good news our machines are in the cable plant and they are learning. They have been deployed into the cable world and they are finding the nasty impairments we knew were there. Machine learning and PNM are making the technician’s job easier on many levels. It’s much easier to find the impairments, it’s significantly easier for technicians to know what

3 06, 2021

Recommendations to resolving DOCSIS 3.1 cable modems crashing with OFDMA

Mia Colabrese2021-06-03T12:49:12-04:00June 3rd, 2021|

Recommendations to resolving DOCSIS 3.1 cable modems crashing with OFDMA Place OFDMA channels above 42 MHz: For those fortunate with 5-65 MHz or 5-85 MHz return paths, keeping four 6.4 MHz SC-QAM signals below 42 MHz and then loading one OFDMA channel above 42 MHz is ideal. Your SC-QAM channels should be fully optimized with dynamic profile modulation up to 64-QAM. Then, by placing your OFDMA channel above 42 MHz, you’re ensuring its likely to be in a low noise environment. A bonus is that subscribers with in-home amplifiers

3 06, 2021

Cable Modems Crashing with OFDMA

Mia Colabrese2021-06-07T14:51:59-04:00June 3rd, 2021|

Why are the DOCSIS 3.1 Cable Modems Crashing with OFDMA This too shall pass. Yes, we’ve seen this before: OFDMA + DBC = BSoD Yes, you have experienced it. Either as a subscriber or technician. The cable modem is on but there is no data flowing through it. Reboot the modem and it works again. It’s the equivalent of the Microsoft Windows blue screen of death (BSoD) and it’s back with a vengeance for cable operators running DOCSIS 3.1 OFDMA with a noisy upstream. What gives? I will

23 04, 2021

Dynamic Range Window OFDMA Troubleshooting

Mia Colabrese2021-08-15T11:48:19-04:00April 23rd, 2021|

Dynamic Range Window (DRW) and OFDMA Upstream Troubleshooting. Tips, suggestions and recommendations. Another power hour of cable with Brady Volpe and John Downey CMTS Technical Leader at Cisco. More and more operators are introducing OFDMA into their networks and experiencing a learning curve with its introduction and Dynamic Range Window issues. Find out ways to overcome these issues and ask any questions you may have. The discussion is on all things DOCSIS. Basic recap of Dynamic Range Window also see our previous OFDMA podcast or live stream. Dynamic

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

23 02, 2021

OFDMA Troubleshooting

Mia Colabrese2021-08-15T16:10:19-04:00February 23rd, 2021|

OFDMA Upstream Troubleshooting. Tips, suggestions and recommendations. Another power hour of cable with Brady Volpe and John Downey CMTS Technical Leader at Cisco. More and more operators are introducing OFDMA into their networks and experiencing a learning curve with its introduction. Find out ways to overcome these issues and ask any questions you may have. The discussion is on all things DOCSIS. OFDMA "UPSTREAM" Troubleshooting: General intro OFMDA Upstream. The A means upstream 50% increase in upstream traffic Noise in return Cable Modems locking up CM locking up

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

7 01, 2021

NanoVNA Calibration to 75 Ohm for CATV

brady2022-07-04T19:38:55-04:00January 7th, 2021|

NanoVNA Calibration for CATV 75 Ohm This article focuses on calibration of the NanoVNA to a 75 ohm environment. There's a lot of talk about the NanoVNA with calibration, the NanoVNA come's standard with 50 ohm SMA connectors on it, but for CATV broadband networks we must calibrate to a 75 ohm standard and not the 50 ohm cal standards that come with the NanoVNA. There are a lot of discussions on the forms about calibrating and that's the proper way of calibrating nano VNAs for a 75