Dashcam RFI (was: Sudden RFI)

[n0xvz]

As seen in this thread, I have an IC-2730a installed in my 2018 F-250. In the past two weeks, I've started receiving a lot of static/RFI on two, specific repeater pairs (146.94 and 146.90) I have programmed into the radio. I've tried adjusting the squelch, but still have interference with the squelch fully closed. Using other radios, I haven't heard the same static/RFI on the same frequencies, so I doubt it's the repeaters.

I'm not sure what has changed. The antenna and power connections haven't changed since the radio was installed and everything has worked fine until recently. I did take the remote head off or security while parked in a public area, but I've done that since the radio was installed. The only other electrical change is finally hardwiring my dashcam. Though, I don't remember this problem starting right after I ran the power. Other than that, there is no other new equipment on the truck itself.

The only thing unusual has been our above-average rainfall, but the weather hasn't been a factor in the past. Plus, I would expect drier weather to cause the problem, not wet weather.

I probably won't have time to dig into finding the source until this weekend, but I'm posting this mostly to share my thinking and to see if anyone has suggestions.

 

[mmckenna]

Does the issue happen no matter where you are? As in, does it follow the truck, or is it just one specific location?

If the dash camera uses a 12v - 5vdc converter, I'd start looking at that. A lot of those low end converters are really noisy on some frequencies.

 

[n0xvz]

Does the issue happen no matter where you are? As in, does it follow the truck, or is it just one specific location?

It's the truck, not one specific location.

If the dash camera uses a 12v - 5vdc converter, I'd start looking at that. A lot of those low end converters are really noisy on some frequencies.

That's what I was wondering as I was typing up the post. I don't think it was doing that when the converter was first installed. Is that the kind of thing that can develop over time? Would it help to shield the actual converter that's part of the cord? If so, what would work? Aluminum foil?

 

[RFI-EMI-GUY]

Portable USB Chargers and factory installed USB Charger ports.

 

[n0xvz]

Portable USB Chargers and factory installed USB Charger ports.

I haven't had trouble the the factory SUB ports nor the SUB charge(s) I use. The only thing SUB that is new is the trashcan power mentioned above.

 

[AK9R]

Do you have anything plugged into a cigarette light socket? If so, remove it and see if the noise goes away.

For that matter, do you have anything in the truck that the manufacturer didn't supply, other than the radio? If so, remove the non-OEM gear and see if the noise goes away.

Another possibility would be to track down every computer in the truck and make sure that they are grounded properly.

 

[mmckenna]

USB adapters...
My son had a USB adapter for his Nintendo Switch. Driving across Northern Arizona one winter and my wife's truck starts throwing tire pressure sensor fault codes.

I stopped to check the tires. All OK. I think about it for a bit, pull the plug on my son's game, issue resolves. He plugged it back in about 30 minutes later, and the warning light pops back on.
Replaced it with a better USB adapter and never had that issue again.

 

[tweiss3]

I know the LED screen dash on my '15 transit creates a ton of 70 cm, enough to open squelch on my D74a when sitting in the front seats. I did notice last night with the air on getting in, there appeared to be a 2m pulse, and that the first time I had the AC on and noticed it.

Try turning the AC off and see if it goes away. I don't have any problems in my radio, but I pulled power from the rear fuse panel, which appears to be filtered from the front. you could be RFI from the AC coming in the power line.

 

[n0xvz]

For that matter, do you have anything in the truck that the manufacturer didn't supply, other than the radio? If so, remove the non-OEM gear and see if the noise goes away.

Nothing new other than the dashcam power mentioned above. On the way home today, I powered off the dashcam and the RFI went away. So, I think I'll need to figure out a way to better shield the converter I have. I don't want to replace it as it's not that great of a camera (but does the job).

Replaced it with a better USB adapter and never had that issue again.

Yeah, I thought I was careful in picking one out, but it appears that might not matter. The power converter even has a ferrite choke built in.

 

[n0xvz]

Update: I thought I had isolated the problem to the USB converter that powers the dashcam. Today, I tried eliminating that power source and trying a USB battery pack. Ugh... the same RFI on the same frequencies. It looks like it's the camera after all. It seems to only affect the IC-2730a and not the scanner I have. It also does not affect the HT I tried. So, it looks like I'll be in the market for a new dashcam. Does anyone have experience with one that works with ham radio (and maybe an IC-2730a specifically)?

 

[AK9R]

Look in the IC-2730 manual for some sort of "clock shift" or "IF shift". That may reduce the radio's response to RFI from your dashcam.

 

[n0xvz]

Look in the IC-2730 manual for some sort of "clock shift" or "IF shift". That may reduce the radio's response to RFI from your dashcam.

The manual says the IF exchange,"Sets to exchange the Intermediate Frequency between left and right bands to avoid interference." Turning it on hasn't eliminated the RFI according to the S-meter in the quick test I did, but it may have reduced the impact a little. In my short test, with the squelch fully closed, no static broke through the squelch. So maybe a breakthrough?

 

[mmckenna]

What is your power feed like? Is it directly off the battery, or did you tap into existing wiring?

 

[n0xvz]

The radio is direct off the battery. The dashcam taps into the fuse panel and a ground. But...using a USB battery instead of the wired converter has the same RFI problem.

 

[mmckenna]

OK, sounds like you are getting it narrowed down.

Cheap electronics and RFI go together like crap and flies.
I don't have a dash cam, but I've thought about it. If you find a good one, let me know. I don't want one bad enough to spend a bunch of money on one.

 

[n0xvz]

I just remembered this thread and thought I'd provide an update. So it definitely was the dashcam. After my F250 got rearended in August (timing coincidence, not related to the accident), the cheap, Chinese dashcam gave up the ghost. I replaced it with a Rove R2-4K and the RFI had nearly gone way. I still see a higher RF floor, but I'm able to keep the squelch set to a reasonable range instead of maxing it out. So I'd rate the Rove as much more radio-friendly.