Cable modem interference!

[W9JAM]

Hey guys. I haven't been able to sign in because I forgot I hadn't switched my emails around. Hoping for some help here. I have a problem with both of my hand-helds. When I key up on any freq in the 2m or 70cm bands it power cycles my cable modem regardless of where I am in the house. There are two cable modems. Comcast Business class since two of the roommates work from home. I need some help here. I can't have the cable modems power cycling when I key the radio. It does it even on low power. Neither radio has been modified. Anyone else had this problem and if so how did you fix it or find a work around? Thank you in advance for any help.

w9jam
Jeremiah A Mulford
Indianapolis, IN

[suddenseer]

I would suspect crappy connectors first. The cable company should fix the problem. I have transmitted 100 watts of rf just inches from the modem with no problems. I have seen a wireless computer router wreak havoc with a cable modem. Those modems can be sensitive to stray rf. If the problem persists with proper connector changes, then you can make a filter for pennies provided you know the frequency the modem operates. These cheap class 15 gadgets don't like ham radios some times. If you don't have time you can pick up a filter at Wally World for about $15.

[n6hcm]

^ what he said.

[kb2vxa]

That's a strange twist, network and computing devices usually make a mess of radio reception, not the other way round. If the cable leaks THAT badly you can expect crap on a receiver where TV frequencies overlap radio services, something that drove me nuts for years. Back in Lizardbreath it made a wide area 2M repeater useless and every time I transmitted anywhere on the band channel 18, a popular sports channel got clobbered. One leak was so bad I could point my BMF TV/FM antenna at it, switch from air to cable and watch free cable TV! At first a neighbor blamed it on me but thankfully he was reasonable and when I told him to complain to the cable company he did. They replaced everything on the poles but they have no control over somebody's crap indoor wiring so at least most of the problem was resolved. Down this way it's Comcast, they're smart enough to leave channel 18 blank and are careful with leakage so I don't get crap on my scanner.

[K0RGR]

I think I'm seeing more reports of this kind of thing out of Comcast customers lately. Are these the same model of modem, same manufacturer?

This is 100% Comcast's problem. I hope they are willing to help.

My cable modem is about three feet from my 100 HF rig and several VHF/UHF HTs.

[n0iu]

I have transmitted 100 watts of rf just inches from the modem with no problems.

Same here:


(Ignore the red arrow. It points to a powered USB hub. I used this picture in another forum. I deleted the original and am too damn lazy to take another picture.)

Both the modem (an Arris TM822 cable modem) and wireless router (D-Link DIR-615) are sitting right next to each other on top of the PC which is (obviously!) right next to the radio. Computers and their peripherals can indeed play in the same sandbox as radio gear.

Add one more vote for having Comcast resolve the issue.

[kb2vxa]

Cumcast, to borrow a phrase from Lawrence Welk; wunnerful wunnerful. I have problems of my own, I can navigate to Tank FM Community Radio 2WET 103.1 in Kempsey, NSW, AU where a ham friend is a presenter but the audio streams are blocked. This happened when Cumcast replaced the old cable modem. The landlord provides internet on the cheap via his business account (no e-mail so I have it with my private domain on a different server), his LAN with the whole place wired so I discussed the matter in detail but all I get is lip service, oh well.

For Kelli et al if you're reading this, re your comments about LPFM being a failure, community radio is alive and well in Australia. I used to listen to Tank, thanks to an ACMA rule they broadcast mostly Australian music and I love their kind of Country & Western but no more.

[K7SGJ]

Same here:


(Ignore the red arrow. It points to a powered USB hub. I used this picture in another forum. I deleted the original and am too damn lazy to take another picture.)

Both the modem (an Arris TM822 cable modem) and wireless router (D-Link DIR-615) are sitting right next to each other on top of the PC which is (obviously!) right next to the radio. Computers and their peripherals can indeed play in the same sandbox as radio gear.

Add one more vote for having Comcast resolve the issue.

Those arrows are handy for storing test leads and such............huh?

[n0iu]

Those arrows are handy for storing test leads and such............huh?

And they make you really popular at Halloween parties!

[kb2vxa]

That corny shit on Laugh In where the picture came from was popular too. I was one of millions of horny red blooded American men who drooled over her, now I'm no longer horny and just drool.