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View Full Version : Solved my own RFI problem


KC2UGV
08-05-2014, 07:56 PM
So, turns out, my keyboard doesn't like RF nearby, so I looked around, and I sent an email to ARRL tis to see if they have any ideas for new keyboards (MFJ-551 is a PS2 only). They suggested a common mode choke.

So, I made an "ugly balun" from the keyboard cable, with 10 turns and some tape. All set for up to 40W out :)
WØTKX
08-05-2014, 08:22 PM
Well, I might be able to hear you, even on SSB. :stickpoke:
KC2UGV
08-06-2014, 04:58 AM
Well, I might be able to hear you, even on SSB. :stickpoke:

I think I'd have no issue up to 100W, but at 40W my keyboard starts either doubling keys or certain keys not working. It's the only issue I'm seeing. I think there's no problem with the station setup right now, as I don't get things like noise over speakers, GFCI outlets tripping, etc etc. Just the keyboard connected to the computer right next to the radio.
kb2vxa
08-06-2014, 10:51 PM
If you run more than 40W for digital modes 100% duty cycle will fry your output module so you're good to go. Besides, if you need more power there's something wrong with your station, station. (;->)
K7SGJ
08-06-2014, 11:00 PM
I think I'd have no issue up to 100W, but at 40W my keyboard starts either doubling keys or certain keys not working. It's the only issue I'm seeing. I think there's no problem with the station setup right now, as I don't get things like noise over speakers, GFCI outlets tripping, etc etc. Just the keyboard connected to the computer right next to the radio.

You may want to try a couple of those split ferrite beads that you put around the keyboard cable and either snap together, or tywrap together. I'd put one at each end of the keyboard cable. You may be able to find a couple on an old modem telco cable.
KC2UGV
08-07-2014, 06:40 AM
You may want to try a couple of those split ferrite beads that you put around the keyboard cable and either snap together, or tywrap together. I'd put one at each end of the keyboard cable. You may be able to find a couple on an old modem telco cable.

That's my thought, going to grab a couple from Rat Shack, and try them out (I don't think I have any laying around right now).
PA5COR
08-07-2014, 02:55 PM
Round Ferrite bar from an old AM radio, ideally to wind microphone cords around and working great reducing RF too...
KC2UGV
08-07-2014, 03:24 PM
Round Ferrite bar from an old AM radio, ideally to wind microphone cords around and working great reducing RF too...

... and I think I've got a couple of those somewheres...