Dexter
On further examination the problem seems more insidious than just the single capacitor in the audio section.? Each bidlrectional amplifier has its owm small capacitor and apparently contributes to the problem.? It now looks like the TX ang RX power feed lines may need some conditioning.
Arv
_-_
Sent from my Verizon, Samsung Galaxy smartphone
toggle quoted message
Show quoted text
-------- Original message --------
From: Dexter N Muir <dexy@...>
Date: 7/31/18 5:45 PM (GMT-07:00)
Subject: Re: [BITX20] Spurious RF at beginning of CW transmission in the uBitx
So for BITX40 a diode in series with R111 blocks C11 from supplying Q16 as well. Now supply that diode direct from +12, no on/off of U1 and less current through K1 pin 3. R111 can then be either reduced (to 10) or eliminated/shorted.
