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Jay864

join:2013-07-18
Reviews:
·Comcast

[Signals] Why is my modem broadcasting wifi when wifi is disabled?

My modem, a Comcast provided ARRIS TG862G/CT, had it's wifi disabled by a tech over the phone. The wifi light has since been off and I thought I was good to go. Today I received my RF meter in the mail and testing it out in my office I could not understand why the baseline readings were so high. It took me a few minutes to narrow it down to the modem. The readings are off the chart, this thing is cranking out a wifi signal continuously and the only way to get it to stop is to unplug the power and yank the battery out.

So even if the wifi light is off and Comcast tells you wifi is disabled, it is NOT! Apart from the health concerns when exposed to RF continuously, why is this box broadcasting 24/7? What is being broadcasted/advertised? Since I can't see the wifi network, what channel is it broadcasting on? Is it interfearing with other equipment?

I have not had time to call comcast yet but I doubt they have an explanation for this (probably need to speak to a TIER 2,3,4 or 5, wherever the actual knowledge begins.

Any thoughts from users on this forum?


train_wreck

join:2013-10-04
Antioch, TN
Reviews:
·Comcast
said by Jay864:

the health concerns when exposed to RF continuously

mind giving a citation for this, as it pertains to wifi frequency ranges?

also, if your RF meter can give you decimal point readings for the frequency the signal is transmitting on, i believe you could infer the wifi channel from that. but don't quote me on that one.


Jay864

join:2013-07-18
Reviews:
·Comcast
I should not have mentioned that as I do not want to drift off topic But yes I believe there are adverse health effects of RF radiation.

My meter only measures as far as 2000%u03BCW/m2 (0.002W) which it reaches and exceeds immediately after powering on, several feet away is where it starts dipping under 2000.


DrDrew
That others may surf
Premium
join:2009-01-28
SoCal
kudos:16
reply to Jay864
What kind of RF meter?

Being that the modem is an RF device, with an RF receiver AND transmitter independent of any WiFi, if the coax cable connecting to it were loose or damaged you might pick up a signal.
--
I'll make it work.... hand me that BFR.


train_wreck

join:2013-10-04
Antioch, TN
Reviews:
·Comcast

1 recommendation

reply to Jay864
actually come to think of it you don't need an RF meter, i know Linux has the "iwlist" command which scans for all APs around you (hidden or not) and displays their associated frequencies, down to 4 decimals. I'm sure Windows has to have some equivalent. So just run this kind of program on a laptop near the thing, and see what you get.


telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15
reply to Jay864
said by train_wreck:

actually come to think of it you don't need an RF meter, i know Linux has the "iwlist" command which scans for all APs around you (hidden or not) and displays their associated frequencies, down to 4 decimals.

If you have a Wi-Fi equipped Android tablet or smartphone, there is an app named "Wifi Analyzer" by FarProc that I use that displays all the Wi-Fi signals (by Channel/Level with SSID) in the area.


train_wreck

join:2013-10-04
Antioch, TN
yup that too, it's a good'un. although i don't know if it would work with hidden APs such as OPs

you could always build a farraday cage around the modem if you're super super paranoid!


Jay864

join:2013-07-18
reply to DrDrew
The meter is a Gigahertz Solutions HF35C. It has a speaker in it as well so I recognize the sound that WiFi signals create and to make sure I have compared it to quite a few other radiation sources including a few wifi routers.


Jay864

join:2013-07-18
reply to train_wreck
Got a tool like that that works on a Mac?


Jay864

join:2013-07-18
reply to telcodad
Just iOS here, they stripped all those fun wifi analyzer apps from the App Store a while ago, real bummer :/


Darknessfall
Premium
join:2012-08-17
kudos:6
Do you see a xfinitywifi network?


Jay864

join:2013-07-18
Reviews:
·Comcast
I don't. I just checked with a utility WiFi Explorer, a few networks around but none of which I can identify as coming from that modem.

Not sure if this utility shows hidden networks though.
Going off of MAC addresses I see none that correspond with the MAC addresses of the modem.


KA3SGM
- -... ...- -
Premium
join:2006-01-17
West Chester, PA
kudos:1
Reviews:
·Comcast
·Cricket Broadband
·Verizon FiOS
reply to Jay864
said by Jay864:

...the only way to get it to stop is to unplug the power and yank the battery out.

Unplugging, yes, but the battery is to backup the phone, not to power the WiFi.

Are you sure it's actually WiFi you are picking up on battery power only?
--
ROCK 'TIL SUNSET


Darknessfall
Premium
join:2012-08-17
kudos:6
Reviews:
·Frontier Communi..
·Comcast
·AT&T U-Verse
reply to Jay864
In your situation I suggest that you either:
1)IF you HAVE phone service, attempt to get an eMTA modem without router functionality by either getting them to swap it out or test your luck purchasing one and buying your own router.
2) IF you DO NOT have phone service, you're better off buying your own modem and router to have more power over the wireless portion of these devices.


Darknessfall
Premium
join:2012-08-17
kudos:6
reply to KA3SGM
Should be noted that the battery causes the wireless to stay up unless a firmware update changed that.


Jay864

join:2013-07-18
Reviews:
·Comcast
reply to Darknessfall
I tried to get my old docsis 2 modem back which had no built in wifi but comcast said every box everywhere was being upgraded to these docsis 3 models and they sent the old ones back to the warehouse. I wouldn't mind purchasing my own, guess I don't have a choice unless they can really kill the wifi in this one (it's a good box otherwise despite of the wobbly and insecure firmware i've been told). I do have phone service (was cheaper that way)


Darknessfall
Premium
join:2012-08-17
kudos:6
Reviews:
·Frontier Communi..
·Comcast
·AT&T U-Verse
said by Jay864:

I tried to get my old docsis 2 modem back which had no built in wifi but comcast said every box everywhere was being upgraded to these docsis 3 models and they sent the old ones back to the warehouse. I wouldn't mind purchasing my own, guess I don't have a choice unless they can really kill the wifi in this one (it's a good box otherwise despite of the wobbly and insecure firmware i've been told). I do have phone service (was cheaper that way)

I would check to see if there's a hidden network. Sometimes they mistake turning wireless off for turning off an ssid.

If you have a windows computer try inSSIDer 3. InSSIDer 3 is usually better when sniffing out hidden networks.


Jay864

join:2013-07-18
Reviews:
·Comcast
Just called comcast, they logged in to the modem and confirmed wifi is set to 'off'. They even reprovisioned it and restarted it twice, WPS and wifi light are off but the signal keeps going. They had, of course, not a single clue what I was talking about.

Will look for a utility that can show hidden networks on a Mac, I know there are a few just have to recall the name.


Darknessfall
Premium
join:2012-08-17
kudos:6
Reviews:
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·Comcast
·AT&T U-Verse
said by Jay864:

Just called comcast, they logged in to the modem and confirmed wifi is set to 'off'. They even reprovisioned it and restarted it twice, WPS and wifi light are off but the signal keeps going. They had, of course, not a single clue what I was talking about.

Will look for a utility that can show hidden networks on a Mac, I know there are a few just have to recall the name.

Try live chat and tell them to put it into bridge mode. This will make your modem act as a modem/phone device only(no router functions) and only one Ethernet port will work. Check to see if there is anything being detected. If you still can see something even after they properly put it into bridged mode, then there's something else up.

FirebirdTN

join:2012-12-13
Brighton, TN
kudos:1
Reviews:
·Comcast
reply to KA3SGM
said by KA3SGM:

Are you sure it's actually WiFi you are picking up on battery power only?

A valid question-OP Can you positively identify it is in the WiFi freq range?

Although its possible the router keeps the WiFI RF oscillator and final amp running [and just not broadcast any data], that would seem kind of a waste in today's "green" society.

Are you sure you are not just picking up RF from the normal electronics/line driver transceivers in the unit?

-Alan


Jay864

join:2013-07-18
Reviews:
·Comcast
reply to Darknessfall
I forgot all about that, glad you mentioned it! The modem is set up in bridge mode, had this done some time ago when i first got the box. DHCP is handled by my ZyXel box. Wifi, when needed is handled by an AirPort Extreme which I rarely use anymore. All ethernet traffic is done through a TP-Link 16-port switch.

Just scanned with a utility that can show hidden networks (KisMAC), while I do see two hidden networks they are not likely coming from the modem as their signal is next to 0. The rest is all AT&T, Netgear and 3 networks that I know are my neighbor's.


news

@videotron.ca
reply to Jay864


camper
Premium
join:2010-03-21
Bethel, CT
kudos:1
Reviews:
·Comcast

2 edits
reply to Jay864
said by Jay864:

Got a tool like that that works on a Mac?

 

Try inSSIDer.
»www.metageek.net/support/metagee···rchives/

Be caerful though, the current version will cost you $20.

The older versions from the download page I cite remain free of cost, so far as I know..

Oops, looks like the MAC OS-X version is $5 at the app store.


Jay864

join:2013-07-18
reply to news
Whoa, did not know about that! Surely that must be what's going on then? Do you know of a way to disable that feature? (can I even confirm my modem/area/state is part of this?)


Jay864

join:2013-07-18
Reviews:
·Comcast

1 edit
reply to camper
I'd spend the 5 bucks but the Mac version does not mention anything about hidden networks. How can I be sure the feature is present?

I found the zip code check on their site, nothing in a 10 mile radius from me so I guess it is not active in this area yet. Maybe the feature has been enabled even though it's not being used yet.


DrDrew
That others may surf
Premium
join:2009-01-28
SoCal
kudos:16
reply to Jay864
said by Jay864:

Whoa, did not know about that! Surely that must be what's going on then? Do you know of a way to disable that feature? (can I even confirm my modem/area/state is part of this?)

You'd confirm it by seeing public CableWiFi or XfinityWiFi networks being broadcast. You've seen neither.
--
I'll make it work.... hand me that BFR.


train_wreck

join:2013-10-04
Antioch, TN
Reviews:
·Comcast
reply to Jay864
yeah, so this seems like an errant broadcast signal getting sent from the unit that shouldn't really be there. since it doesn't have a name or visible presence, and your scanning utility didn't show any semblance of a normal wifi AP on the modem, then you're probably ok. i doubt it would be possible for anyone to actually associate with it or actually connect to your network.


Kill_All_WiF

@comcast.net
reply to DrDrew
said by DrDrew:

You'd confirm it by seeing public CableWiFi or XfinityWiFi networks being broadcast. You've seen neither.

Unless Comcast's method of disabling the xfinitywifi service in the gateway is to just turn off the SSID rather than killing the radio. And since the gateway only has one radio for both the xfinitywiri service and the customers private WiFi, they may not turn off the radio in order to avoid interfering with the customer's private WiFi.


Jay864

join:2013-07-18
Reviews:
·Comcast
reply to train_wreck
Comcast support is calling me back tomorrow to see if the signal can be disabled completely. Not too worried about unauthorized access as I have a zyxel firewall and managed switch now between the modem and my network. Just want the signal gone. If it can't be disabled I may as well leave wifi on 24/7, not the plan. Will update the thread if anything interesting comes out of this, thanks for all the feedback so far


Jay864

join:2013-07-18
reply to Kill_All_WiF
makes sense. I'll be asking about it tomorrow though.