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4G cellphone interference with Motorola Comcast box in DC

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Member Since: ‎01-18-2012
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4G cellphone interference with Motorola Comcast box in DC

Comcast Motorola cable box 4G interference in DC A friend recently switched to a 4G phone and whenever he came over my cable (many channels) would pixelate and freeze or go black. This never does this any other time. Initially i thought it was a service issue, but i called the service center and they could not diagnose any issue. Today he was over and he had his phone out and was texting and I noticed that simultaneously the cable would malfunction. We moved the to the next room and texted with no issue but within 10 feet of the cable box any text message or 4G data would cause disruption. When he received data via wifi there did not seem to be an issue, only when he sent/received texts or switched off his wifi and used the 4G for data. There are a few prior reports of this happening, mainly in Europe. The issue seems to be some sort of MHz interference issue.
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Member Since: ‎10-18-2008
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Re: 4G cellphone interference with Motorola Comcast box in DC

Did you read what Jay wrote and check your connections?

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Member Since: ‎02-15-2008
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Re: 4G cellphone interference with Motorola Comcast box in DC

I am having the same problem.  Whenever I text with my 4G phone, or getting driving directions, I am noticing that my cable tv picture freezes the first 10 minutes that I am on my phone.  This happens when I am texting at home, and it also happens on my office tv as well.  Each time, comcast customer service people tell me there is nothing wrong with my tv service.  Strange indeed.  This confirms to me that we should not have these phones near our heads all the time.

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Cable Expert

Member Since: ‎03-02-2007
Posts: 17,628
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Re: 4G cellphone interference with Motorola Comcast box in DC

Make sure your F connectors are snug at the back of the box, and the TV outlet.


it most likely is a bad shield on the coax.  If your using the cheap coax cables with cheezy gold connectors that come with many pieces of equipment like a VCR, replace them with high quality RG6 with compression connectors.  You can pick up some quality jumpers at the local Comcast office.


If the jumpers to the wall are RG6 with compression fittings and are snug, then there might be other coax issues in the unit or home with poorly shielded coax as some are not 100% shielded.  Most likely then every inch of the coax would need to be gone over to check for damaged shielding and loose or corrorded fittings.  Everything that is crimp on / twist on or press on connectors need to be replaced with compression fittings.


The shielding from the grould block on the outside of the home to the cable box must be 100% fully shielded so it won't leak just as your plumbing can't leak.


All it takes is one loose or poor fitting to cause your issue.  Every point there is a fitting needs to be fully inspected and replaced with compression fittings.