Even my 2m Kenwood D710 mobile in my car will break squelch on some drive throughs.
Tesla had a similar issue when someone started taking them too close to radio towers up on the hills. Luckily they were able to build a foil shield so they could get the RFID spot to pick them up.
Where can I find such a thing?
T-Mobile will now send a full femtocell that uses your ISP's net and broadcasts both WCDMA and LTE. It's much better.
Although these days, with Wi-Fi calling for voice and Wi-Fi itself for data, the need for these devices is lower and lower.
Bugger, those prices!
(We have the LED's to replace them but finding times to do so is a problem.)
I would start with just listening broadband with an SDR for a while, just to see what's really going on. Something ought to become visible in the spectrum, at least intermittently.
Once you get the pattern, you could simply move around and measure the relative intensities, map the numbers, and the epicenter ought to become more or less obvious. Then close in with the SDR, watching the levels on the screen, and hopefully you will walk right into the culprit.
An RTL-SDR is a few bucks on Amazon. The software is free. The only other thing you need is a laptop.
Would work just fine with a single dongle, a laptop, and a usb gps device or cell phone, just would have to do a few more drive arounds in different frequency bands.
They sell a fancy dongle that works 'better' than an off the shelf model but this $10 model will work just fine for learning: https://www.aliexpress.com/item/USB-2-0-Software-Radio-DVB-T...
I'd also suggest seriously considering getting an amateur radio license. It isn't difficult or expensive in most countries, you'll learn a lot about radio in the process and you'll gain the right to transmit on a wide range of frequencies. The /r/amateurradio wiki is a useful starting point.
I did recently get an rsp1a as an upgrade once I realized how much fun I was having. It seems better at rejecting noise but otherwise isn't that different than my rtl-sdr. I need to get a windows install so I can use sdruno instead of cubicsdr, though.
+1 on looking at getting a license though. It opens up a whole new world of experimentation and capabilities. Even on 2m I still get a kick covering 80-100mi with our local repeater network.
RTL-SDR Blog R820T2 RTL2832U 1PPM TCXO SMA Software Defined Radio with 2x Telescopic Antennas https://www.amazon.com/dp/B011HVUEME/ref=cm_sw_r_cp_apa_i_gk...
Portable Antenna Bundle with 7M... https://www.amazon.com/dp/B07DPNPK4D?ref=ppx_pop_mob_ap_shar...
You can do nothing about it. What you are hearing is the beginning of a GSM transmission. GSM frequencies are well-known to be easily picked up by audio circuitry. Switching to LTE should solve it.
Hmm? All GSM frequencies are also LTE frequencies.
GSM “buzz” occurs with GSM (TDMA) phones,” he said. “It is when the phone is communicating with the tower on the GSM control channel, which is not power regulated and can be as high 1 watt, depending on the phone model. It is pulsed data bursts and does not happen on the LTE side (the reason CDMA phones remain relatively quiet).”
Phones using GSM standards cause most buzzing. Phones using LTE and CDMA rarely do. GSM networks are less common than they used to be, but are still ubiquitous, and even non-GSM phones may “step down” to other networks for various reasons.
But once you get the right gizmo plugged in, and the right app running on the laptop, it's literally as simple as walking around looking at a spectrum graph. Sure, you can do more fancy stuff, but for the basic level that's it.
ready to locate signals out of the box
Specifically, $27ish dollars shipped, and basically the cheapest still reasonable way to get into SDRs. Receive only though, so while you can explore the spectrum below about 1.9ish GHz, you can't play with it
It's ~$150 USD (if I remember correctly)and has a range of 385 to 3800 MHz @ 20MHz bandwidth, but a very simple hack increases it to 70 to 6000 MHz range @ 56MHz bandwith. Check here for more info on the hack: https://www.rtl-sdr.com/adalm-pluto-sdr-hack-tune-70-mhz-to-...
Basically they were looking to see if it was the source, and the guy banged the pole with a hammer, and the banging showed up on the listening station some 20 miles away.
That said, if there's a bolt on or near the primary, it's possible it worked it's way out and started mechanically vibrating making contact between some induced voltage and ground say.
The gambling parlor next door were using jammers to keep "fish table" players from cheating. This was affecting key fobs, car starts, etc. in a pretty big radius around the location.
Oh, they will. The FCC do not mess about when it comes to intentional interference.
As it's aerial, in some places it's above ground with, you guessed it, car parks below it.
The tow trucks make a killing with it because you (or your insurance...) pay a full towing charge but your car only need to be towed like 5m for it to open again.
Funnily enough, the RF interference does not prevent closing of the cars, only opening :)
If you hold the dead fob against the little key symbol on the steering column it'll power the fob by induction and you'll be able to start the car.
You're right, older fobs that just do keyless entry may not be able to start the car though.
The poster a couple levels up said people where paying full towing price to have cars moved 5m. If you can put the car in neutral you should be able to push it that far yourself.
The main problem would be having a locked driving wheel (common in France), which may make pushing it 5 meters away impractical/impossible without lifting the front wheels.
And there is something to be said for not being that guy who says "should have read the manual!" when another human being, however flawed, gets stuck in a situation they don't know their way out of.
It seems like it would be worthwhile for the industry to come up with a standard symbol for “hold your key fob here to make it work when the battery is dead” and print it on the appropriate spot on the car.
So there are definitely circumstances where the phi’s always artifact alone just isn’t enough to start the car, only to get in.
If I transmit with a two meter ham radio handheld near any of them at night, the light turns off! When I stop transmitting, the light comes back on.
I haven't taken any time to troubleshoot this, but it would be interesting to learn just why a two meter signal makes the light turn off.
Turned on the ham radio - in scan mode - picked up someone talking, but noticed a bunch of static also being picked up. Didn't think much of it until I turned off the lights and the static went away. radio antenna was about 4 feet away from 2 diff bulbs (!).
These things are noisy ..thinking about trying a few diff brands to see if there is a difference.
also thinking about borrowing a buddy's spectrum analyzer to see if I can isolate the frequencies of the noise, might be able to put a a filter on the antenna.
Personally, I’d just cover the bulb in a few layers of grounded chicken wire. But I’m cheap like that.
Shielding the bulb won't help when the switching PS in the bulb is making the house wiring resonate. RFI problems frequently fail to yield to silver bullet solutions.
(shrug) RF is hard.
Also, I've replaced the headlights on my car with LEDs. Much better visibility now, but the FM radio performs much worse. I'll have to figure something out, it's annoying.
"After investigation it was determined that there was faulty consumer electronic equipment stuck in transmit mode in the area, which was causing the interference. ... In this case, it was determined that it was a remote car starter. It has since been deactivated and the interference has stopped ..."
Story time: a few years ago I used to work in a building which was intended for many more workers than we actually were there (some floors were completely empty). The garage was big and had parking places for a lot of us, but we were only given a few electrionic keys for the garage door. A lot of us, including me, came to work by bus, so basically there were parking places for all of those who came by car, yet we only had like 10 keys for 20-25 people.
We knew that the keys were easy to disassemble and reassemble, so we devised a solution: using arduino, we created a device that (via a cheap prepaid SIM card) was capable of receiving phone calls, and when any of our numbers called the device, an actuator pressed the internal components of the electronic key. Pointing this device to a window near the garage door was good enough. So, every morning, people called the number of the device, and just by doing that, the door would open automatically.
The thing is: it always worked at the evening, between 16 and 18h. But in the mornings, and especially in cloudy or misty mornings, sometimes it wouldn't work. We tried to investigate but we never knew why this was.
I wonder if a similar phenomenon is happening here.
Well, atmospheric conditions have pretty well known effects on electromagnetic transmissions; the presence of water, particularly, interferes with (both scaterring and attenuating) signals that would transmit well through dry air.
Here's a plot from when we discovered LED motion sensing lights use a radar signal on the upper end of 5Ghz. Every vertical line is another light. You can imagine a hallway filled with 20+.
Carstairs is 60 km north of Calgary where you find the Calgary Amateur Radio Association (mission: "Have Fun and Serve our Community"), University of Calgary Amateur Radio Club and other organizations, all of whom would be thrilled to break out their spectrum analyzers and nail this to the wall for free.
I’ve used this for assessing some harmonics of 4-5 MHz clock lines causing issues.
The Red Pitaya is a particularly compelling alternative from a hardware hacker's perspective, because it does double duty as an extremely versatile measurement and data acquisition device.
If you're just getting into SDR, I would just get a $20 RTL-SDR, and then move on to something like the HackRF or BladeRF later.
been lusting after one of the little guys for some time now.
I'm also kind of salty that they dropped the MicroUSB variant of the full-size model. The Mini makes sense to have it a "stick" format, the full one does not. The full one having an A connector on it has been nonsense from day one.
I still will probably end up buying one because they're still the best bang for the buck.
Just use a rubberducky antenna (a stick - heck, just a piece of wire), and measure relative intensities in a few points on the map. That will give you an idea where the epicenter is.
Then walk through that area while keeping an eye on the intensity. I betcha you will bump right into the culprit.
I have a keyless-only car now, and this sort of stuff worries me. "Dead battery" mode has always saved me thus far, but in that situation? I'd be hosed. Can't even put it in neutral and coast down the mountain. (Electronic transmission, there's no shift-interlock bypass...)
Did you read the Valasek/Miller paper on the Jeep hack? For me, the technical details were all well and good, but the most interesting bit was right in the intrioduction -- Their research was funded by DARPA.
Consider this: Everyone knows that water supplies and power grids are critical infrastructure. Bridges and tunnels, too. Transit, obviously -- an attack on the NYC subways would cripple the city. That's all understood and appropriately protected.
But imagine an attack that caused 10% of the cars on the road right now to simply turn off, and not turn on again. Some folks would pull to the side, but a lot wouldn't, and the roads would be an obstacle course for quite some time, while every tow truck scrambled to clear them. In my mind, that's just as crippling as shutting down a subway or an airport.
Individual vehicles haven't been thought of as critical infrastructure in the past, because they weren't vulnerable to that sort of attack. But they're becoming so, and in the most haphazard, security-what-security, if-it-compiles-ship-it, sort of way. And I think DARPA's goal in sponsoring this sort of research is to force people to realize that.
Because you bet the bad guys already know it.
You can do this with a $26 antenna on a $25 RTLSDR on a $5 OTG cable plugged into any random Android phone. It takes a minute to install the spectrum analyzer app, probably two minutes to plug everything together, and about a minute per "reading". The rest of your time is spent driving.
This is a massively fun hobby I would encourage anyone reading this to consider. Start at the rtl-sdr.com blog and read some archives, there's a ludicrous amount of stuff within the reach of this incredibly cheap receiver.
In the US, I've rented cars that sound the main horn every time you lock the car. Bizarre.
I was thinking I might connect the 12V for the horn to the ACC, so it can only beeps when ignition is on, but I haven't got around to that yet.
Yes, it is a legal requirement, which in practice could void an insurance claim, or a criminal case if I hurt someone, but sometimes you just have to make a choice.
At least if OP follows through on running his car through his key, he'll be safe. (How about using a relay attached to something that's powered during key-on?)
I guess it's just for finding your car in big parking lots? Seems like a different button could be dedicated for that far less common use case.
It's certainly possible though, these are usually called "2 way remotes": https://www.compustar.com/what-is-2-way/
Without 2-way communication, the remote has no way of knowing if the vehicle acted on the signal.
If there's nobody around you can hit the panic button too.
There are some cars that use the car (not alarm) horn when locking so maybe their central locking system is connected to it, although it never looked like a factory option, rather an OEM alarm or something similar.
I haven't noticed cars anywhere else doing this, but I'm not that well traveled.
See: http://www.legislation.gov.uk/uksi/1986/1078/regulation/99/m... , https://www.legislation.gov.uk/ukpga/1972/20/section/196/ena...
https://www.racfoundation.org/motoring-faqs/mobility#a6 suggests it's about 35% of vehicles in large settlements.
I don't find it too bothersome, but maybe I'm just used to it. In some other videos people are suggesting that it can be disabled on most vehicles by holding the lock and unlock buttons simultaneously for 2 seconds.
Every GM vehicle I have ever owned honks (via the car's horns) on the 2nd lock.
(a) there is not a seperate alarm horn (b) removing the horn, also disables the 2nd lock honk.