I had removed the "Extra" purple wire that is an ADC input often used for an S meter.? I assume that you have a v3 or v4 ubitx (I have the version 4).? You explained in one of your posts that the problem goes away when you ground the output connector on the uBitx with your hand.? That is pointing to the RF coming back on the shield of the coax.? Do you have a 1:1 balun on the dipole?? If not, again I would look to grounding and adding the balun.? MFJ or others make both baluns and full cut antennas.
Have you tried grounding the case?
If problems persist, I would also look at adding ferrites on the control lines from the encoder to the Raduino board.? That was one of the things I tried, again, helped but the grounding and ferrites on the feed to the antenna were the things that solved it for me.
I would also verify that you are not over driving the audio: I could reduce the problem by lowering my mic gain.? This also reduces the power out, so may be just a function of the correct frequency and power getting back to the nano.
Since all was well with the plastic case, I am still leaning towards the RF coming back down the coax brain, and surrounding the nano.? If there is unbalanced RF on the braid, putting the uBitx in case that is not grounded may not have helped.
From another post:
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Fri, Nov 30, 6:56 AM (3 days ago)
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I had the same issue, however on 20m.? Traced it to rf riding the coax braid back from an off center fed dipole (MFJ-2010).? Solved it by grounding the shield before the radio, and placing a ferrite snap on core over the coax (RG8x) between the ground point and the connection to the radio.
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Tried the ground only first, and it helped (could raise the power out to 6 watts), then added the ferrite to get it back to peak at 14 watts without causing the menu selection.? I did not have any issues on 40m.
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My setup (using RG8x, PL259 connectors and PL259 Lightning arrester for grounding) is:
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uBitx ======== SWR/PWR Mtr== Arrester ======== OCFD
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? ? ? ? ? ? Ferrite? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Ground (water pipe in basement)
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Hope that helps.
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Evan
AC9TU
