Very odd Ingress/Interference issue affecting Key Fobs in small area

kgowen44

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Hi there,
we are having a rather strange issue. Since Sunday, many of the neighbors in the area are having issues with their keyfobs. In additional, a couple are having an issue with garage doors as well. In may cases, when activating the keyfob, nothing happens. After multiple tries, sometimes it will work. If they drive down the street a few houses, they work fine. I even drive my car over to the area and had the same issue. To make it even more odd, there are TWO Ford fusions (2015 and 2020) that are not affected. Cars affected are 2 KIA models, one 2019 and one 2020. 1 Dodge Ram, and 2 jeeps. 3 of these cares have push button start and do not work as well during times when FOB quits. This issue is oddly intermittent. Here what we have tried

1) Changing batteries
2) Driving down the street (Issue corrected once we left the small area affected)
3) Tried street behind the homes- Issues did not occur
4) Walked around neighborhood using close call function. No hits except for FM radio channels.

Anyone have any ideas? Perplexed big time here.
 

Whiskey3JMC

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Anyone have any ideas? Perplexed big time here.
Move! haha. I'm by no means a pro at this but if you grab an SDR dongle and laptop/tablet and search around 315mhz, see if you get a signal. Move around in different directions to see if it gets stronger to get a general sense at where the source could be. This article mentions a number of potential sources

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ScannerSK

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there are TWO Ford fusions (2015 and 2020) that are not affected.
One website states Ford Fusions use 902 MHz remotes instead of the typical 315 MHz frequency so this likely explains the difference.

Definitely use "AM" mode not "FM" mode to find interference. AM will allow you to detect a lot of things that cannot be detected using FM mode.

Shawn
 

a417

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'20 Ford = 902 mhz
'19 Kia = 434 mhz
'20 Kia = 434 mhz

now, without knowing the FCC IDs off the affected units, or the years of the Dodge / Jeep units, this is what google pulls up for what we know.
Maybe start looking aroung 433-434 mhz rather than 315?
 

eorange

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Check if any of your neighbors suddenly have outdoor LED string lights around fences, pools, homes, or LED spotlights. I know of 2 cases where this affected a garage door opener and a wifi keyboard.
 

statewide97

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this was an issue years ago when military bases started to use the 380mhz trunked systems.
 

spacellamaman

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had my smart meter, jam my driveway alarms for about a week once. over night they started blasting something around 433.935 or so and driveway alarms were all 433.92. really really strong and constant signal. fcc id for that meter showed NO auth for any freq even near the 430mhz range but nearly everything else. not a good sign.

so i called the power company and explained/complained, was told the meters didn't operate on that freq, which i had actually told them that first, but was emphatic with them that it was happening, and i really needed this situation resolved.

while friendly and courteous, i made sure they understood, that i was going to be a real pest til this stopped, it hadn't done this in the 3-4 years i had had the meter and whatever this was obviously wasn't normal operation. and a day later.....it stopped. never again. weird things happen so don't rule out anything
 
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a417

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had my smart meter, jam my driveway alarms for about a week once. over night they started blasting something around 433.935 or so and driveway alarms were all 433.92. really really strong and constant signal. fcc id for that meter showed NO auth for any freq even near the 430mhz <snip>
how did you find out that it was the meter?
 

spacellamaman

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how did you find out that it was the meter?
used signal stalker with a PRO668 and a PSR800. the power meter was the last thing i would have thought of too.

normally stuff that is 433.92 is so low powered i have to turn the squelch all the way down but this thing was blasting enough that i eventually got a close call hit from about 10 feet with the right antenna on a uniden 436. all my receivers for the driveway alarms were in the house the meter was on so that helped too.

if it had been a neighbor or something i would have never known. you could hear it in the background from over a quarter mile out with the squelch down.
 

krokus

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'20 Ford = 902 mhz
'19 Kia = 434 mhz
'20 Kia = 434 mhz

now, without knowing the FCC IDs off the affected units, or the years of the Dodge / Jeep units, this is what google pulls up for what we know.
Maybe start looking aroung 433-434 mhz rather than 315?
All the FCA stuff I have seen has been 300 MHz.
 

kgowen44

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What would be the best way to track signal? I tried close call on an SDS100 and only received FM radio.
 

ScannerSK

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What would be the best way to track signal? I tried close call on an SDS100 and only received FM radio.
Any scanner tuned to the affected frequency in AM mode should reveal the interference.

On the SDS100, enter Hold mode and then enter the frequency including the decimal point. I don't recall how to change the SDS100 to AM modulation after a direct entry. From your description it sounds as if the signal is rather weak so it likely will not trip any type of close call. You'll likely have to walk around with the scanner to locate the source of the interference.
 
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