Re: I7SWX PTT Pop Mute

Arv Evans All Messages By This Member #31734 Gian? I7SWX The charge and discharge of various capacitors have always been a problem from the very first BITX20 design.? Seems that this is the price we pay for simplicity and easy of understanding.? Initial testing was performed with a digital sampling oscilloscope.? Triggering was set to start the sweep on PTT activation and again on PTT deactivation.? The 2nd probe was used to monitor voltage across the mixer diodes.? This revealed the diodes being biased ON during the first 20 ms of transmit mode. Monitoring the transition from Tx to Rx with a similar setup showed a voltage pulse into the audio amplifier that coincides with the infamous BITX-Click on transition to receive mode.? Solving this may be somewhat complicated because there are several bypass and coupling capacitors that play a role in the situation. Arv? K7HKL _._ toggle quoted message Show quoted text On Wed, Aug 23, 2017 at 7:26 AM, Giancarlo via Groups.Io <i7swx@...> wrote: Hi Arv, thanks for your comments and feedback. How did you detect those capacitors being trouble? 73 Gian I7SWX

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