Strange signal right near the frequency my pi-star hotspot is on.

[Thorndike113]

I happened to turn my SDR's on this morning to see what I could hear. I got down into the 433 MHz range and for some reason I noticed a bunch of different weird data bursts. On the waterfall they were anywhere from tiny little dots to lines all the way up to a signal that was 500 KHz wide. They seemed to transmit every 20-30 seconds. What bothers me is that I have the output frequency set to 433.50 MHz on my pi-star and this signal is around 433.9575 and the other smaller signals are a little lower or higher by up to 20 KHz. I read about smart homes having devices on this frequency. I live in the country and while we do have next door neighbors we have good sized yards between us and them with the exception of the new neighbors on one side of us. Our houses are close enough that I can get his wifi pretty well in my place. We dont have smart devices in this house so I am confused as to what is so strong inside of my place to produce a 500 KHz wide signal. I even shut everything down around me and I still picked up the signal. Its a weird garbled squeal that lasts for about a split second. My concern is if the next door neighbor has smart devices, am I interfering with him? I never see him or his wife as they stay locked up in the house 24/7 unless they go out to the store which is done by getting in their vehicle in the closed garage. I know he just put up a really nice security cam outside of his place facing us. Is it possibly that. I am not sure what he has for wireless technology other than his router.

 

[walsabrook]

Do you have a wireless indoor/outdoor thermometer? My outdoor sensor does something like this around that freq ?

 

[a417]

433 is rife with devices, smart home stuff (which you said you didn't have)...doorbells, gate alarms, garage door openers, home weather stations, IoT...there's a lot of things it could be.

 

[mmckenna]

Yep, common Part 15 frequency. It can get pretty noisy in some areas.

Remember, Amateur radio is a secondary allocation on 420-450MHz frequencies. Federal is primary with radio location stuff. Part 15 allows low power stuff on 433MHz.

 

[walsabrook]

Signal on my weather station thermometer is so wide I hear it on my 70cm handy talkie when it “chirps” every 30 seconds or so

 

[RFI-EMI-GUY]

I bought a deep freezer in the midst of the Covid lock down here in Panic Town. I also bought a two sensor wireless freezer thermometer and put both sensors into the freezer and set both channels to give me an alarm if the freezer failed. Sure enough a year later I am getting alarms on first one then the other sensor. Tried new batteries, reset the thing,, crazy, can't fix it. So I turn my service monitor on and there is this strong dead carrier around 434 MHz jamming it. I rigged up a portable and go around the house and discover I have a weather station thermometer mounted outside which is also on that freq and is continuously keyed up. Changed batteries on that and reset it.

 

[KB2GOM]

I bought a deep freezer in the midst of the Covid lock down here in Panic Town. I also bought a two sensor wireless freezer thermometer and put both sensors into the freezer and set both channels to give me an alarm if the freezer failed. Sure enough a year later I am getting alarms on first one then the other sensor. Tried new batteries, reset the thing,, crazy, can't fix it. So I turn my service monitor on and there is this strong dead carrier around 434 MHz jamming it. I rigged up a portable and go around the house and discover I have a weather station thermometer mounted outside which is also on that freq and is continuously keyed up. Changed batteries on that and reset it.

As the cartoon character Pogo once said: "We have met the enemy, and he is us." My Grundig Satellit 800 interferes with my Uniden 396. Go figure.

 

[Thorndike113]

Haha I didn't think there would be this many replies but it seems this is a common issue.

We do in fact have a wireless thermometer outside that I was under the impression was on 2.4GHz. Took my little CCR and put it on 433.9575 with the antenna removed and went up to the thing and as soon as the light turned red (transmitting) the same noise came out of the radio that I heard on my SDR's.

Thank you everyone. Problem solved. I just didn't want to mess anything up with my DMR Hotspot.

 

[w2xq]

Thank you everyone. Problem solved. I just didn't want to mess anything up with my DMR Hotspot.

Assuming you are using PiStar, make the change in the Dashboard. Nothing to mess up...