coax vs electrical homeruns

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egnlsn

egnlsn

Senior Member
Location
Herriman, UT
Occupation
A/V/Security Technician
I used to sell these all the time. Sometimes people would have humbars in their pictures, sometimes it was a 60Hz audible hum. Whichever it was, I had a lot of positive feedback. They've since been replaced by these.
 
hbiss

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Keep that TechToolSupply link to that isolator for the next time somebody comes here and complains about voltage on their cable drop or it's burning up or cable boxes or TVs are getting damaged. Nobody knows what we are talking about.

-Hal
 
tortuga

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
hbiss said:
If you are a sub or contractor for the cable company
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Yeah probably not a NEC issue more like a cable co spec.
For a office building I worked on I had to run an empty 2" EMT per the cable company specs. I asked if it could be smurf tube or 1" EMT and they said no. I was picturing them running a little piece of RG6 (or whatever you call it) in it and thought man this is way overkill, but when I went back later they had a big fat coax in there, looked like 750mcm.
 
synchro

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
Like mentioned above, it's unlikely that 60 Hz is interfering with the digitally modulated RF signal and even if it did, it wouldn't manifest itself as a hum in the detected audio. It's possible, though, that a ground loop is conducting 60 Hz interference into analog audio stages that are after the RF signals are detected and processed. In this case an isolator that has "DC blocking" on the outside shield such as the one in post #23 should be effective. However, there may be bonding/grounding issues that are the root cause of the interference.
 
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