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RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Sun May 14, 2017 10:17 pm
by zand
I bought a new RTL-SDR Dongle V3 and it seems that it knocks out all the wireless networks on my street after a few minutes of use. At first I thought it was just mine but latter found out that my neighbors are having there phones and computers lose connection all at the same time.

Re: RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Mon May 15, 2017 12:06 am
by rtlsdrblog
The V3 and all RTL-SDR's are in fact incapable of transmitting anything so I don't see how it could be knocking out WiFi...

Re: RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Mon May 15, 2017 1:06 am
by zand
rtlsdrblog wrote:The V3 and all RTL-SDR's are in fact incapable of transmitting anything so I don't see how it could be knocking out WiFi...
That's what I thought as well. I had it happen 3 times on my laptop and a 4th time using rtl_tcp while its connected to an Ubuntu server without a wireless nic.

It seems to be more than a coincidence as it happens after a few minutes of use and never happens for hours while its not being used. Not shore if I just have a bad unit that starts causing interference after a period of time. When the wireless goes down for everything the dongle still picks up signals but the Wireless stays down until I terminate the program that is using the dongle.

Re: RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Mon May 15, 2017 10:46 am
by rtlsdrblog
zand wrote:
rtlsdrblog wrote:The V3 and all RTL-SDR's are in fact incapable of transmitting anything so I don't see how it could be knocking out WiFi...
That's what I thought as well. I had it happen 3 times on my laptop and a 4th time using rtl_tcp while its connected to an Ubuntu server without a wireless nic.

It seems to be more than a coincidence as it happens after a few minutes of use and never happens for hours while its not being used. Not shore if I just have a bad unit that starts causing interference after a period of time. When the wireless goes down for everything the dongle still picks up signals but the Wireless stays down until I terminate the program that is using the dongle.
If it was causing interference it would should show up on the spectrum itself. It would have to be fairly powerful to knock out WiFi, and exceptionally powerful to knock out the WiFi all over your street. Any possible LO leakage coming from the RTL-SDR's clock simply wouldn't be strong enough to even cause a dent.

Are you using rtl_tcp at all times? The more realistic scenario is that rtl_tcp is saturating the network connection and causing problems with your router being unable to handle the traffic.

Re: RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Mon May 15, 2017 4:22 pm
by zand
rtlsdrblog wrote: If it was causing interference it would should show up on the spectrum itself. It would have to be fairly powerful to knock out WiFi, and exceptionally powerful to knock out the WiFi all over your street. Any possible LO leakage coming from the RTL-SDR's clock simply wouldn't be strong enough to even cause a dent.

Are you using rtl_tcp at all times? The more realistic scenario is that rtl_tcp is saturating the network connection and causing problems with your router being unable to handle the traffic.
First 3 times it was connected to my laptop with gqrx connecting directly to it. Thinking that it being connected to my laptop had something to do with it, I hooked it up to a local server and used rtl_tcp along with gqrx on my laptop and had it happen a 4th time.
I am thinking about trying to run just rtl_fm on the server while sending the output to /dev/null and seeing what happens after I get out of work today.

My best guess right now is that its a faulty nic that starts fuzzing the networks that is somehow triggered by the dongle.

Re: RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Tue May 16, 2017 1:30 am
by zand
Ran rtl_fm for over an hour on my server and had no problems. Than removed the Wireless and Bluetooth cards from my laptop then ran gqrx with the dongle directly connected and after a while noticed my phone and other devices loss connection to the network. After stopping gqrx everything connected after a couple of minutes.

I am pretty much at a loss right now but, I thank you for taking your time to try to help me out.

Re: RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Wed May 17, 2017 12:26 am
by zand
Today I tried running it with out the antenna attached and lost connection on my phone within 8 minutes. After noting that SSID Broadcasts are still going out fine but was unable to connect, I logged into the access point/router over a wired connection and found that the config page for the Wireless fails to load but the other config pages load fine. After stopping gqrx the config page for the wireless loaded fine. Had a different couple that lives 200ft/61m down the road visit me to use my internet because theirs went down.

Re: RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Sat May 20, 2017 8:08 am
by zand
Well I finally had it happen while not using the dongle so I'm considering that it was just coincidence and I just had a stroke bad luck.

Even though I still don't know why it been happening, I am considering my problem resolved since I now have proof that I can present when people try to clam that it was a result of my recent actions.

Re: RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Mon May 22, 2017 2:19 am
by snn47
Which frequencies are the wireless networks affected operate on and how far away from you were they affecte.

Do you use an additional LNA or
do or your neighbours have an active TV amplifier left over from terrestrial reception times,
use a portable TV antenna with built in amplifier (rabbit ears and smaller directional yagi)?

Any broadband amplifier can pick up other signals, amplify, oscillate and generate more signals that might interfere. Cheap active TV antenna and amplifiers are known to oscillatate, e.g. to sweep/interfere very slowly.

If you are still concerned about the dongle, connect a 75 Ohm termination connect it to ensure it's terminated and place it in a can and ad a choke to the USB cable and if availbale place it in the cellar to increase shielding. While this does not completely shield the dongle it should reduce it sufficiently to prove that the dongle is not the source.

Re: RTL-SDR Dongle V3 knocking out Wireless Networks

Posted: Tue Oct 17, 2017 9:34 pm
by zand
Hate to come back here again. 5 months ago I ruled what was happening with my 2.4Ghz access point to be caused by a firmware bug as even when the AP radio was disabled in the configuration it was still transmitting and handling clients so I replaced it with a different one. During that time I hadn't the time to mess with the SDR unit. During those 5 months I had no problems with my wireless networks accept yesterday and today I started messing with the dongle again on a new system that has no network cards and after a few hours had every system that was connected with the new Access Point lose connection and act up. Even a laptop I have stopped even detecting networks until after a reboot.