How to detect a Cell Jammer?

[colodak]

This may sound totally odd, but I'm hoping some more exp. folks have some ideas. On the weekends I drive for Lyft and Uber in the Denver area. At the airport, we have a holding lot, several fellow drivers have commented that it feels like a cell dead zone, as it's not uncommon to sit in certain areas and never get a ping for hours on end, and then suddenly there will be multiple pings. This most commonly seems to happen on the Uber Select side of things.

Now, the discussion seems to be is someone jamming cell signals in at least part of the lot. Several people have suggested this, while I partially buy into it, I have my doubts, because about 50 yds from the holding lot is the main the Denver TRACON FAA facility, and I would think that any jammer in the area would also cause interference with them, as well the rent a cop service has their office nearby as well.

A few weeks back, in the middle of a busy day, Airport ops and multiple Denver cops came rolling through the lot and parked in one corner of the lot. They then began to slowly roll thru each aisle of the lot before parking by the main entrance. A few drivers who were there that day said as soon as the cops parked by the main entrance, suddenly the pings began to fly, especially on the Uber Select side, it was as if someone opened a faucet.

All this leads me to this question, is there an easy way to detect if someone is running some type of jamming device in the area, do they make something reasonably priced that can be used?

I have my Tech license, and have sat in the lot with my 2m/70cm handheld (connected to an external antenna) and it seems awful quiet, as well as using the handheld I can monitor air traffic and have on occasion noticed dropouts.

 

[mmckenna]

Spectrum analyzer. Prices run from cheap for a cheap one to ridiculously expensive for a ridiculously expensive one. The bigger issue is knowing how to properly work it and interpret what it's telling you. These are not consumer products and are not necessarily easy to use.

I'd suspect it's not a jammer, though. Could be any number of things…
Interference. While the Tracon is no where near cellular frequencies, high power transmitters can overload the cellular receiver. There are also a lot of other sources of RF in/around airports.
Cell overloading. Every time a plane lands, a few hundred people turn on their cell phones. Likely not an issue as the cellular system would be designed to support that.
I suspect what you are seeing in the "waves" of messages is that when a plane lands, a bunch of people request a ride, then the messages fly out.

Jammers that impact cellular service are usually low quality and simply blanket the cellular bands with a bunch of noise. Since many public safety systems operate in adjacent frequencies, this would impact them, also. A public safety agency would likely notice that radio coverage was severely impacted in a specific area.

More than likely, it's a social thing. Drivers expecting to get riders, they don't get them, so they look for reasons.

Looking at the time stamps on the messages might tell you something.

 

[iMONITOR]

All airports are overwhelmed with strong RF interference, on numerous frequencies. Aircraft, buses, cabs, PD/FD, security, ground/maintenance crews, food/drink vendors, CB/FRS/GMRS, cellphones, Wi-Fi, and of course numerous radar signals, etc.

 

[mikewazowski]

You wouldn't happen to be in a parking garage as they make great Faraday cages.

A cell jammer wouldn't fly at an airport. The carriers likely have an inbuilding system which would be affected by the jammer.

 

[RFI-EMI-GUY]

This may sound totally odd, but I'm hoping some more exp. folks have some ideas. On the weekends I drive for Lyft and Uber in the Denver area. At the airport, we have a holding lot, several fellow drivers have commented that it feels like a cell dead zone, as it's not uncommon to sit in certain areas and never get a ping for hours on end, and then suddenly there will be multiple pings. This most commonly seems to happen on the Uber Select side of things.

Now, the discussion seems to be is someone jamming cell signals in at least part of the lot. Several people have suggested this, while I partially buy into it, I have my doubts, because about 50 yds from the holding lot is the main the Denver TRACON FAA facility, and I would think that any jammer in the area would also cause interference with them, as well the rent a cop service has their office nearby as well.

A few weeks back, in the middle of a busy day, Airport ops and multiple Denver cops came rolling through the lot and parked in one corner of the lot. They then began to slowly roll thru each aisle of the lot before parking by the main entrance. A few drivers who were there that day said as soon as the cops parked by the main entrance, suddenly the pings began to fly, especially on the Uber Select side, it was as if someone opened a faucet.

All this leads me to this question, is there an easy way to detect if someone is running some type of jamming device in the area, do they make something reasonably priced that can be used?

I have my Tech license, and have sat in the lot with my 2m/70cm handheld (connected to an external antenna) and it seems awful quiet, as well as using the handheld I can monitor air traffic and have on occasion noticed dropouts.

It very well could be one of the established cab companies has an employee jamming the signals. Or it could be that the cellular company has insufficient capacity to serve the lot. A spectrum analyzer would be the way to see if the network is being jammed. You would have to search the correct band and channels for your service, and sometimes that information is elusive.

If you contact your cellular carrier they should be very concerned about getting jammed. The FAA would be concerned as well being that they manage ALL spectrum at the major airports. Here in Florida, a commuter got annoyed at people driving and texting so he installed a multiband jammer in his car. The cellular companies were able to predict his daily route by looking at dropped call data at sites along the highway. He got caught.

You ask about a simple way. A wide band field strength meter connected to an antenna in your car might give you a strong indication of a nearby jammer. Circling the lot a few times you might get a look at the vehicle where the jammer is installed.

I will have to concede that the lengthy dead periods interrupted by periods of multiple pings is indicative of flight arrival schedule more than anything else.

 

[KB7MIB]

You get your pickup requests on a phone app, correct?

In my phone, I can go into my settings, and then into Phone Info. Under that, there is Network Settings. Under that, I can check Network Strength, etc.
Go through your phone and see if you can find something similar. That may tell you how strong the network coverage is in that lot, or if it varies widely. Have your fellow drivers do the same, in case they're on different networks. (Sprint, Verizon, et al)

John
Peoria, AZ

 

[zz0468]

The best way is with a spectrum analyzer, but you gotta be able to recognize the big blob of noise for what it is.

 

[RFI-EMI-GUY]

The best way is with a spectrum analyzer, but you gotta be able to recognize the big blob of noise for what it is.

That's true. Plus in the environment of an airport, you will need some bandpass filtering or that spectrum analyzer will be bombarded with radar pulses.

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