Some updates to improve PTT clicking

1 files changed, 15 insertions, 2 deletions

diff --git a/README.md b/README.md
index bf30d8d..e2dc30b 100644
--- a/README.md
+++ b/README.md
@@ -34,6 +34,12 @@ very first trial.
 Later, the external bandpass and 2x SPF5189Z were replaced by an internal bandpass with less insertion loss and a single
 SPF5189Z.
 
+
+*First 3cm QSO done with Picardy 2020 as IF transceiver on 2020-02-21*
+
+Using a Downeast Microwave 10368CK transverter.
+
+
 TODO
 ====
 
@@ -47,7 +53,7 @@ Open questions
     * Not tested, but plan B done (J306)
     * Use an additional PWM output for plan B?
   * Put sidetone volume setting before RV303?
-    * Hook up to LM375 BYPASS?
+    * Hook up to LM386 BYPASS?
 
 Issues
 ======
@@ -65,7 +71,14 @@ Issues
   * Unintended effect: removes LCD backlight
 * C319 and C326 are redundant
 * BC856W wrong footprint
-* R327 upsets DC offset of audio amp, capacitive decoupling needed
+* R327 upsets DC offset of audio amp, added 2.2uF capacitive decoupling in series with 1k
+  * PTT makes loud click, assemble with 100nF only, still loud
+  * Connected LM386 back to 8V, through 0 Ohm instead of 10 Ohm (was on 12V through 10 Ohm because DCDC noise). Still
+    loud.
+  * Investigate other muting schemes.
+    * Connecting BYPASS to GND generates click
+    * 2N3819 based muting according to G3YCC works better.
+  * Assemble 1k + 100nF for coupling, revert to 12k for R329, use 20k for R326 to slow down the transition a bit
 * 2m LPF from LimeRFE use values I don't stash
   * 20pF done with 2x 10pF
 * SW: ADC input for buttons looks messed up...