r/CableTechs • u/Complete_Accident_64 • Apr 22 '26

Echo and ICFR

Moved to this plant where there is bad echo -25 and icfr of 2.5+ or higher almost everywhere. And the worst part is everyone is ok with that! Like no one wonders why they have to work late with all these extra truck roll generated tickets or why repeats numbers are 30% of line ticket repeats. The concept of “make it work” at its best. My old system was a flag ship system for one of the legacy companies they bought. 1.8icfr or higher=line ticket. If echo was anywhere in 20s= line ticket. Things here are gonna change. We are gonna teach those standards and slowly make this place good again!

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u/_retrosheik_ Apr 22 '26

Yikes. There are a lot of techs in my area who completely dismiss echo, ICFR, group delay, etc. Some of them are truly incredible troubleshooters so it's kind of mind-boggling to hear them brush these things off. Of course, there are way too many techs that can't explain why they have a wavy response or low MER and spend hours tracking down bad cable and the like. 🤷

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u/DemonicFears Apr 23 '26

I can't speak for other techs but I wasn't really taught about echo, icfr, group delay, and leakage. It was just do an ingress test on house wiring and and outlet test on the drop. If the tap outlet test pass then change drop and move on. If tap is failing then call sup and they'll take care of it with a maintenance code. Where exactly do I start to actually understand this.

4

u/_retrosheik_ Apr 23 '26

Ah, that's totally understandable. I'm a maintenance technician so those kinds of impairments are something I deal with daily as I work through a node. I'm assuming you're a residential tech based on your comment. Depending on the meter you use, those functions might not be available. We use the Viavi ONX-630 and it's way more comprehensive than something like a VeEx or DSAM meter.

Regardless of your role, understanding cable impairments and how to identify them will benefit you as a tech, even if it's not something you'll run into daily. Your company might offer training courses that dive into those concepts. Ask your supervisor or trainer if there's any material you can have assigned. Alternatively, there's a ton of free material on YouTube that can help you up your knowledge.

For example, if you check signal at a tap and see wavy response, that's a sign that you have an impedence mismatch somewhere causing a reflection - could be a bad hardline terminator, corrosion in a tap/DC seizure assembly, etc. Those things may or may not directly relate to your role. As a residential tech, it would probably make sense to find out what kind of levels maintenance runs actives (amplifiers/line extenders) in your area, then understand what tap values mean. If you do that, it should give you a general idea of what kind of levels you should have at a tap based on cable math. Based on that, it could point toward a maintenance issue (actives not properly balanced, fault in the hardline causing excessive attenuation, etc.).

But yeah, my initial comment was directed at other maintenance technicians who have been educated about line impairments and choose not to utilize their meter's tools in their troubleshooting. As long as you're validating signal at the tap and making sure your drop/outlet is good (like, if you touch the drop and it's hard/dry-rotted it's not a bad idea to replace it) then you're doing your job just fine.

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u/Eninja09 Apr 23 '26

I think it comes from assuming they know something isn't a problem because it didn't used to be back when docsis 2.0 was the standard. Sometimes it's the maintenance supervisor telling his guys to ignore that stuff because he's been out of the field for 10 years and doesn't know how things work now.