HELP 433mhz interference! RTL-SDR on the Mac OS?

[ranger_rick]

hi everyone. i am new and my speciality is working with machines (motorcycle, cars etc). not radio etc. so i would appreciate some help. I have searched thenet for a solution to my issue but not 100% certain i get it.

history: my remote starter (compustar) has worked flawlessly for several years and it stopped working last week. i did the usual trouble shooting and found that it would work if i was sitting in th cab of the truck or any where other than my house. i contacted the shop where i purchased the remote starter and they installed a new antenna. worked great in their parking lot but as soon as i got home - nothing. i went back down to the dealer - worked just fine. they say interference.

so i started thinking what has changed in my home environment "what would cause interference" and started eliminating potential sources - no change.

i took my truck down the street a little bit and still no change. go a few blocks and all is good. what?

i texted my neighbor and he hasn't installed anything new etc and i find out that he has also has a compustar remote system and it too works on 433mhz. he has no issues. (he is bring his car over tonight to test at my house)

i read that you can find a source by using an AM radio? i tried the high and low of the AM spectrum and while i found "noise" when i was right onto of a device. there was nothing out and around my vehicle. am i doing this wrong?? i also have a short wave?

ok. now from what i read i can get an RTL-SDR dongle and this will help me locate the offending interference. Can anyone recommend hardware/software that works well with a mac.

i will admit that i have no experience in any of this and i am doing my best to read, comprehend and educate myself.

just want to find the source of the interference. i find it very odd that i cn drive down the block and its still an issue, and more over, this ll started last week. suddenly.

that you for your time and consideration - RR

 

[WA0CBW]

A while ago I worked a call at a new strip mall restaurant that cars parked in front of the restaurant couldn't use their key fob for remote starter or door locks. Backing a vehicle away from the entrance across the street and everything worked normally. Turned out the electrician had installed a dimmer and LED lights for the store front that were not rated for for being dimmed.
You might look for new security systems or outdoor lights.

Bill

 

[mmckenna]

There is a number of small consumer electronics that use 433MHz, not just remote start or door lock systems.

A number of the wireless weather stations use 433MHz. There's probably a ton of other things.


I agree with Bill, could be some malfunctioning electronics. LED light sources are a known culprit. But it could also be something perfectly legal that you or one of your neighbors is using. Usually those consumer devices transmit short bursts of data, but something may be malfunctioning. Moving down the street and it starts working strongly suggests it is something within a few houses of yours.

An RTL-SDR might help you see the interference, but tracking it down takes some skill. Once you find it, you have a whole different thing to deal with, getting the owner to shut it off, replace it, etc.

These wireless devices operate on Part 15 frequencies, and one of the rules of part 15 is that:

This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.​

Yes, if you find a neighbor has a device that is causing the interference, you could file a complaint with the FCC, and the FCC —MIGHT— assist you, but I wouldn't hold your breath. It's usually better to approach the owner of said interfering device and work with them carefully to resolve the issue.

 

[ranger_rick]

ok this one is from the twilight zone: I continued my search for the interference and went to the obvious source - the garage door/opener. I opened the garage door and unplugged it from the outlet (not my wiring). I tested the remote starter and it worked!!

obviously there is an issue with the garage door system, right? not so fast

I pressed the remote button to turn my truck off and nothing happened. what the what?

I plugged the garage door opener back in and tried to shut the vehicle done: nothing. unplugged it again and tried to shut it down: nothing. there was a power strip plugged into the same outlet, I unplugged the power strip, pressed the button to shut the truck down annnnnnd it shut down!!?

everything unplugged from the outlet in the garage and I can start and shut down the vehicle without issue.

I have no clue what's going on here. there is one section of unshielded electric wire going to an over head light from the same receptacle. I have no explanation for what's happening.

 

[spacellamaman]

I have had an issue, since resolved, with a smart meter at my house that was suddenly blasting on 432.0 mhz one day, and i have had long experience with cheapo harbor freight driveway alarms using 433.92mhz. the alarm recievers become a real tricky issue when you have them in proxemity to each other, effectively jamming each other due to the noise they put out. the transmitters will be putting out signal, no problemo, but ya can't hear it over the rx'ers.

just some odd things to think about.

 

[ranger_rick]

for me its just really strange that an outlet can cause such issues? and over such a distance. I moved my truck three houses down the street and it still wouldn't work with the remote starter, now that everything is unplugged no issue and my neighbor experienced no issue regardless of distance.

now this is an old outlet with a run of old wiring wiring exiting the box to an overhead light socket. poor insulation?

the craziness of the issue is that the interference wasn't simply 433mhz in nature. my neighbor has the exact same remote starter and he had no issue. the interference was "specific" to my vehicle.

how can an electrical outlet with a garage door opener and a power strip plugged into it generate a specific "noise" that only interferes with my trucks remote start and over such a distance??

bizarre

 

[WA0CBW]

If you plug the garage opener into the outlet directly does it still interfer?
BB

 

[spacellamaman]

for me its just really strange that an outlet can cause such issues? and over such a distance. I moved my truck three houses down the street and it still wouldn't work with the remote starter, now that everything is unplugged no issue and my neighbor experienced no issue regardless of distance.

now this is an old outlet with a run of old wiring wiring exiting the box to an overhead light socket. poor insulation?

the craziness of the issue is that the interference wasn't simply 433mhz in nature. my neighbor has the exact same remote starter and he had no issue. the interference was "specific" to my vehicle.

how can an electrical outlet with a garage door opener and a power strip plugged into it generate a specific "noise" that only interferes with my trucks remote start and over such a distance??

bizarre

three house down, thats right impressive. and might i add you ask a lot of good questions, questions i myself have made to one degree or another in my own situations.

there are all sorts of possible answers that could be correct.
but none are likely to be satisfying answers.

 

[krokus]

Is the plug strip just a plug, or does it have surge protection? Does the switch light up? If so, is it an LED or neon bulb? What else plugs into the strip? What else is on that same breaker?

The RTL-SDR is a cheap way to get a look at the RF environment, but keep in mind they have quite a few self-generated signals, called "Birdies" by most radio people. As already stated, seeing it is there is just part of the battle. Having a portable arrangement can help track down the source, where the signals get stronger. (There are RTL-SDR apps for Android devices, that work well when coupled with an OTG cable.)

 

[ranger_rick]

I rewired the outlet. all new box, wire, outlet etc etc...with power strip and garage door plugged in the issue is gone. I can start the truck remotely and shut it down no problem. there was nothing plugged into the power strip either times. I still find it completely bizarre that problem was specific to my remote starter/key fob etc. my neighbor had the same system and no issues. whatever was causing the interference coded itself to my signal. I think that's freak and cool and I wish I knew how it all happened. and then to have the issue transmit a few houses down blows my mind...the wires acting as an antenna.