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authorMatthias P. Braendli <matthias.braendli@mpb.li>2021-03-05 21:22:57 +0100
committerMatthias P. Braendli <matthias.braendli@mpb.li>2021-03-05 21:22:57 +0100
commitdf04f120a103976631047b08a35c310abfb7f604 (patch)
treed64684081f6c7c921faff6772dcebf7dbefc5fe7
parentef4c18417684920726edaa6d0d01c85acc3a0abd (diff)
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Some updates to improve PTT clicking
-rw-r--r--README.md17
-rw-r--r--kicad/baseband.sch56
2 files changed, 43 insertions, 30 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...
diff --git a/kicad/baseband.sch b/kicad/baseband.sch
index 7439dbe..33ebc72 100644
--- a/kicad/baseband.sch
+++ b/kicad/baseband.sch
@@ -1195,17 +1195,6 @@ Wire Wire Line
10800 4350 10650 4350
Connection ~ 10650 4350
$Comp
-L power:GNDA #PWR0342
-U 1 1 5E53C532
-P 10800 4550
-F 0 "#PWR0342" H 10800 4300 50 0001 C CNN
-F 1 "GNDA" H 10805 4377 50 0000 C CNN
-F 2 "" H 10800 4550 50 0001 C CNN
-F 3 "" H 10800 4550 50 0001 C CNN
- 1 10800 4550
- 1 0 0 -1
-$EndComp
-$Comp
L Device:CP_Small C340
U 1 1 5E54E2B9
P 8150 6250
@@ -1318,18 +1307,6 @@ Wire Wire Line
7200 5800 7150 5800
Connection ~ 7200 5800
$Comp
-L Device:R R329
-U 1 1 5E5DBA37
-P 10750 5550
-F 0 "R329" H 10820 5596 50 0000 L CNN
-F 1 "12k" H 10820 5505 50 0000 L CNN
-F 2 "Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder" V 10680 5550 50 0001 C CNN
-F 3 "~" H 10750 5550 50 0001 C CNN
-F 4 "0" H 10750 5550 50 0001 C CNN "Need_order"
- 1 10750 5550
- 1 0 0 -1
-$EndComp
-$Comp
L power:GNDA #PWR0340
U 1 1 5E604089
P 10650 6200
@@ -1364,7 +1341,7 @@ L Device:R R326
U 1 1 5E64AC63
P 10300 5750
F 0 "R326" H 10370 5704 50 0000 L CNN
-F 1 "1.5k" H 10370 5795 50 0000 L CNN
+F 1 "20k" H 10370 5795 50 0000 L CNN
F 2 "Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder" V 10230 5750 50 0001 C CNN
F 3 "~" H 10300 5750 50 0001 C CNN
F 4 "0" H 10300 5750 50 0001 C CNN "Need_order"
@@ -2448,12 +2425,8 @@ Wire Wire Line
9300 5700 9400 5700
Wire Wire Line
9100 5700 9000 5700
-Text GLabel 10750 5400 1 50 Input ~ 0
-+8V
Wire Wire Line
10600 5200 10650 5200
-Wire Wire Line
- 10750 5700 10650 5700
Connection ~ 10650 5700
Wire Wire Line
10650 5700 10650 5750
@@ -3340,4 +3313,31 @@ Wire Wire Line
Connection ~ 10550 600
Wire Wire Line
10550 600 10750 600
+Wire Wire Line
+ 10750 5700 10650 5700
+$Comp
+L Device:R R329
+U 1 1 5E5DBA37
+P 10750 5550
+F 0 "R329" H 10820 5596 50 0000 L CNN
+F 1 "12k" H 10820 5505 50 0000 L CNN
+F 2 "Resistor_SMD:R_0603_1608Metric_Pad1.05x0.95mm_HandSolder" V 10680 5550 50 0001 C CNN
+F 3 "~" H 10750 5550 50 0001 C CNN
+F 4 "0" H 10750 5550 50 0001 C CNN "Need_order"
+ 1 10750 5550
+ 1 0 0 -1
+$EndComp
+$Comp
+L power:GNDA #PWR0342
+U 1 1 5E53C532
+P 10800 4550
+F 0 "#PWR0342" H 10800 4300 50 0001 C CNN
+F 1 "GNDA" H 10805 4377 50 0000 C CNN
+F 2 "" H 10800 4550 50 0001 C CNN
+F 3 "" H 10800 4550 50 0001 C CNN
+ 1 10800 4550
+ 1 0 0 -1
+$EndComp
+Text GLabel 10750 5400 1 50 Input ~ 0
++8V
$EndSCHEMATC