Re: #ubitx-help #ubitx-help

David S


I agree with all the previous comments about your wiring, it does need sorting.

Looking at your photographs I think your speaker impedance is 4 ohm, the one I have looks the same type but is unbranded.  A 4 ohm is too low for the TDA2822 on 12v, on audio peaks it's going to exceed the output capability of the chip.   I've changed C77 to 22uF and fitted a 47R load, using that point as an audio feed for both a digital interface and one of the cheap TDA2030 modules from China that are on Ebay.  That completely changed the audio on my 1st batch board with an FCI TAD2822.

Although I don't think that's the cause, in your recording it's sounds like "motorboating", that's a type of low frequency oscillating usually due to instability in the power to the audio amplifier.  When the received audio starts, it suddenly pops up and is very clear despite the oscillation.  If that's your normal background noise level I think your quick lucky, mines terrible, comes with living in a built up area.


David  G8DJM

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