Harbor Freight charger causing VHF interference!

[primestar31]

http://www.harborfreight.com/15-amp-three-stage-onboard-battery-charger-maintainer-99857.html

I've been trying to track down why I've been having issues with WJRT-12, which is the VHF (RF12) tv channel around here. All the rest are UHF. I found out that tuning my AM car radio to 530khz, I'd have heavy interference coming into the driveway, and all the way up. My driveway is 220ft long, but the CP power lines parallel the driveway.

I unplugged this HF charger that's been on the backup diesel generator battery in the garage back corner, and the interference STOPPED immediately! I then Googled it, and found out others had the problem with the same charger, and couldn't fix it with any normal method.

So, pay attention to issues like this. I would have never thought that little $20 charger could put out so much EMI, for such a distance...

 

[Mr Tony]

I agree
If you have interference check the oddball things. You never know what could be causing interference

 

[primestar31]

Well, it's 5 am here now, and I have now also discovered that my Dell Latitude E6410 90watt 19volt laptop power brick ALSO causes the VHF "signal quality" level to vary up and down from 100% - 0% and all points in-between at random. It only does this when plugged into the laptop, AND when the laptop is turned on with the battery installed. If I unplug the brick when that quality level is varying, the quality level immediately jumps back to 100% and stays there with no fluctuation! At the same time, my Tivo Roamio stops throwing off RS errors. The laptop and power supply are in my living room, and the power outlets are on the same circuit.

The power supply must be coupling some serious rfi into the AC power lines. I guess I'll be getting a new power supply, and hope they all don't cause this same issue. If so, then I can take further steps to cure it, (filter circuit) or I won't leave it plugged into my laptop all the time.

 

[RONZ]

Harbor Freight does not carry the best products. The general rule with them is if it has a plug on it don't buy it. WJRT signal if fine in my area 70 miles away

 

[FaT Air]

I once had to find the interference to a Sheriff's VHF radio system. Turned out to be an electronic rodent deterrent in a garage 1/4 mile from the radio tower.

 

[primestar31]

I once had to find the interference to a Sheriff's VHF radio system. Turned out to be an electronic rodent deterrent in a garage 1/4 mile from the radio tower.

That's incredible! 1/4 mile away, hard to believe that distance from something like that.

 

[FaT Air]

I was amazed to find it that far from the tower.
For the last couple weeks I have been having a raspy 60hz signal, intermittently, interfering with my VHF scanner. Just 5khz from a channel I monitor. Driving me nuts as I don't have access to a good 'tool' to find it. It's not the streetlights as it happens in the daytime also.

 

[primestar31]

I was amazed to find it that far from the tower.
For the last couple weeks I have been having a raspy 60hz signal, intermittently, interfering with my VHF scanner. Just 5khz from a channel I monitor. Driving me nuts as I don't have access to a good 'tool' to find it. It's not the streetlights as it happens in the daytime also.

I used an AM radio set to 530khz, which is open frequency here. One of those old-school portables. Easy to hold, and very directional...

 

[FaT Air]

I used a spectrum monitor wired to a 4 element yagi back then. Would be 'handy' now. Got an idea that it could be someone's Tx failing. It's definitely 'on channel', and not wide band noise. Doesn't affect anything else.