[RFI] Travel trailer converter RFI solutions

[nm8rmedic]

I was suspicious of it too!   The growl started inside the converter when I placed a mix 31 ferrite on the DC line.  I immediately removed the ferrite core.The ferrite core on the DC line indeed caused the growl to become audible from the converter.The growl from the converter when the ferrite was in place on the DC line was disconcerting enough that I didn't take time to check if it reduced the spurious  HF output.The core was only on the positive line, so not in common mode.I have a mix 31 core that's about 4 in in diameter. I could probably get a couple of turns of both the positive and negative DC lines through it, if that warranted a try.  Go with a CM choke.The mix 31 I placed on the AC line at the input of the converter was common mode. But as noted in my initial post, it had no effect whatsoever. Nor did an isobar power strip with its filtering components.I also did try a large value electrolytic (87,000 microfarad) across the DC line, but no effect.Smaller value capacitors across the DC line likewise made no change.Jim has me wondering if focus on the DC line with a common mode choke holds promise.  The growl from the converter with the choke only on the positive lead made me abandoned that, pronto. Perhaps prematurely.Per WA2LBI's suggestion I also have an inquiry in with Iota regarding their converters.Thanks to everyone who's responded. It is very much appreciated. ScottSent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Jim Brown <jim at audiosystemsgroup.com> Date: 7/22/22  14:53  (GMT-05:00) To: rfi at contesting.com Subject: Re: [RFI] Travel trailer converter RFI solutions On 7/22/2022 11:42 AM, k1ttt.dave at gmail.com wrote:> I would be very suspicious of the growl caused by ferrites on the dc line,Dave,That "growl" (great description) is harmonics of rectangular waves produced by switched-mode power supplies and power control electronics like the controllers for variable speed motors. Growl is not CAUSED by ferrites, SUITABLE ferrite chokes can SUPPRESS it on circuits that carry those currents. The 2-wire transmitting chokes in this link are also suitable in this application. http://k9yc.com/2018Cookbook.pdf73, Jim K9YC_______________________________________________RFI mailing listRFI at contesting.comhttp://lists.contesting.com/mailman/listinfo/rfi