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public:radio:topics:arduino:30m_phasing_rx [28/07/26 14:05 BST] – johnpublic:radio:topics:arduino:30m_phasing_rx [28/07/26 14:23 BST] (current) – [Mute clicks & thumps] john
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 ==== Mute clicks & thumps ==== ==== Mute clicks & thumps ====
  
-I found this arrangement of using diodes to "share" the pull-down transistor switch with the c/o relay to perform poorly.+I found this arrangement of using diodes to "share" the pull-down transistor switch with the c/o relay in the 30m TX [[..:..:..:blog:new_tx_finished | Blog post about TX ]] to perform poorly after I'd used it for a while and realized it needed a bit of a tweak to make it "right" rather than "okay".
  
 I noticed a loud click/thump as the first CW character was sent and the mute operated. Initially I assumed that the MUTE wasn't operating soon enough, or that the QSK wasn't delaying the SI5351 VFO enable line sufficiently long enough to allow the MUTE (and C/O relay) switching. Much probing with the 2-channel scope shows that the relative timing is okay. The loud initial click occurs whenever the first loud audio feeds into the mute circuit, regardless of how long the mute has been active, and how long the RF is delayed. I played with the Arduino code to delay the RF enable so that the RF didn't come on until 100mS after the MUTE and Relay c/o - enough to miss several morse characters - and yet still there was a loud click when the first loud audio arrived. I noticed a loud click/thump as the first CW character was sent and the mute operated. Initially I assumed that the MUTE wasn't operating soon enough, or that the QSK wasn't delaying the SI5351 VFO enable line sufficiently long enough to allow the MUTE (and C/O relay) switching. Much probing with the 2-channel scope shows that the relative timing is okay. The loud initial click occurs whenever the first loud audio feeds into the mute circuit, regardless of how long the mute has been active, and how long the RF is delayed. I played with the Arduino code to delay the RF enable so that the RF didn't come on until 100mS after the MUTE and Relay c/o - enough to miss several morse characters - and yet still there was a loud click when the first loud audio arrived.