Amateur Radio Interference

[Phrede]

My A139 Pro 3ch is causing interference with my Amateur Radio when receiving 443.175MHz. It does it on multiple radios, including a HT, which eliminates any power lead or antenna issues. This must be a camera SE problem.

Anyone else? Thoughts?

 

[Dashmellow]

EMF/EMI issues have come up from time to time on the forum over the years with certain cameras and people have tried various fix-its with varying levels of success.

One solution is to take the camera apart and paint the inside of the housing with EMF shielding paint. The stuff is not cheap but can work or at least reduce the problem. You can find it selling in smaller quantities.

https://www.amazon.com/s?k=EMF+pain...6bfdb7ae5bc6d1f30e9e88d9e4e3436d7bfb941a95d0a

Another approach is to use copper foil shielding tape (often used for guitar pick-ups)

https://www.amazon.com/s?k=EMF+copp...6bfdb7ae5bc6d1f30e9e88d9e4e3436d7bfb941a95d0a

or Farady Fabric

https://www.amazon.com/s?k=Farady+F...6bfdb7ae5bc6d1f30e9e88d9e4e3436d7bfb941a95d0a

or Faraday Tape

https://www.amazon.com/s?k=Farady+tape&crid=9NSK2CI8W4KO&sprefix=farady+tape,aps,185&ref=nb_sb_noss_2

 

[rozwell]

Aren't PCBs in A139 almost entirely shielded? That doesn't have to mean they got rid of everything though...

Have you tried moving the camera closer and further to the radio/antenna to see if that makes a difference?
Did you make sure it's not the power supply itself?
I remember having issues with some USB car chargers which caused lots of radio noise and electric interference in car installation.

I'd suggest using some decent power bank (with a short cable, if possible) to power the dash-cam and making sure it's not the power supply itself - you can even walk around to see the range of the problem.

 

[Aph]

My A139 Pro 3ch is causing interference with my Amateur Radio when receiving 443.175MHz. It does it on multiple radios, including a HT, which eliminates any power lead or antenna issues. This must be a camera SE problem.

Anyone else? Thoughts?

Palomar have a good name amongst U.S. hams. Give them a ring 760-747-3343. They'll be able to advise and will probably suggest slip on ferrite beads or maybe a choke. I know they do a VHF/UHF mobile transceiver RFI/Noise reduction kit for about $20.

 

[Nigel]

My A139 Pro 3ch is causing interference with my Amateur Radio when receiving 443.175MHz. It does it on multiple radios, including a HT, which eliminates any power lead or antenna issues. This must be a camera SE problem.

Anyone else? Thoughts?

Is it interference, or a valid transmission?

443Mhz is a valid band for a dashcam to transmit on, not sure why it would want to, but it is possible that it has a transmitter...

 

[Dashmellow]

Palomar have a good name amongst U.S. hams. Give them a ring 760-747-3343. They'll be able to advise and will probably suggest slip on ferrite beads or maybe a choke. I know they do a VHF/UHF mobile transceiver RFI/Noise reduction kit for about $20.

Good suggestion! Palomar Engineers is a great company. I've owned a number of their products over the years such as baluns and antenna systems.

 

[Phrede]

UPDATE:

Thanks for all the replies. I'll try to address some comments.
It is most definitely RFI. 443MHz is part of the 70cm amateur band and should NOT be used by dash cams. Power supply or antenna location is a non-factor, notice in the OP where I said it happens on multiple radios including my HT, handheld for those unfamiliar.

What I have discovered is that if the rear camera is unplugged the interference stops. I'm thinking the length of the cable to the rear is part of the problem along with it being a thin co-ax. Is the length a harmonic of the frequency?? Also since the problem is only on that exact frequency I'm suspicious of resonance. Viofo is sending some ferrite rings to try. They acted like they had seen this before. Fingers crossed.

I absolutely agree about Palomar Engineering. I've used their products for years and appreciate the info on their website.

 

[Nigel]

They acted like they had seen this before. Fingers crossed.

Probably based on interference to DAB radio in some cars, which can often be improved with a ferrite core. DAB radio is at around 130MHz, so it is highly likely that a ferrite core which works for that will also work for your 433 MHz.

443MHz is part of the 70cm amateur band and should NOT be used by dash cams.

Widely used for remote controls outside of North America, but Viofo's current remote control is Bluetooth.