From b25357b32524a469ca24ad2817e4f151eced265a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakub=20K=C3=A1kona?= <kaklik@mlab.cz>
Date: Thu, 14 Nov 2024 00:17:49 +0100
Subject: [PATCH] Improved readme documentation.

---
 README.md                     | 64 +++++++++++++++++++++++------------
 hw/sch_pcb/QFHBAL01.kicad_prl |  7 ++--
 2 files changed, 45 insertions(+), 26 deletions(-)

diff --git a/README.md b/README.md
index 32d223c..7b6a11f 100644
--- a/README.md
+++ b/README.md
@@ -1,36 +1,56 @@
-# QFHBAL01 - Antenna interface and balun
+# QFHBAL01 - Antenna Interface and Balun
 
-[Balun](https://en.wikipedia.org/wiki/Balun) for QFH antennas
+The **QFHBAL01** module is an [antenna interface and balun](https://en.wikipedia.org/wiki/Balun) designed for QFH (Quadrifilar Helix) antennas, supporting right-hand (RHCP) and left-hand circular polarizations (LHCP). This module enables efficient impedance matching and balanced transmission in QFH antenna configurations.
 
 ![QFH antenna balun](/doc/src/img/QFHBAL01.png)
 
-## Mechanical drawing
+## Key Features
 
-![QFHBAL01 Dimensions](/doc/src/img/dimensions.png)
+- **Polarization**: RHCP and LHCP
+- **Frequency Range**: 4.5 - 3000 MHz
+- **Insertion Loss**: 2 dB typical
+- **Amplitude Balance**: ±1 dB
+- **Phase Balance**: ±20°
+- **Power Rating**: 250 mW max RF, 30 mA max DC
+- **Operating Temperature**: -55 °C to +85 °C
+- **Dimensions**: Diameter 32 mm, Height 20 mm
+- **Weight**: 10 g
 
+## Transformer Mounting Options
 
-## Electrical interface
+The **ETC1-1-13** transformer on the QFHBAL01 module can be soldered onto the PCB in two configurations:
+
+1. **Galvanic Isolation**: Isolates the antenna from the RF line, enhancing protection for the receiver input but potentially increasing insertion loss slightly.
+2. **Direct Galvanic Connection**: Connects the antenna directly to the RF line without isolation, minimizing insertion loss but offering less protection for the receiver input.
+
+These configurations allow customization based on application requirements for input protection and insertion loss.
+
+### Balun Polarization and Connection
 
 ![Balun connection](https://uuki.kapsi.fi/pix/qha/qha-diagram_medium.png)
 
-| Helices | Feedpoint | Radiation | 	Polarization |
-| ------------- |:-------------:| ----- | ----- |
-| Left-hand |	Standard |	Upward |	RHCP
-| Right-hand |	Anti-standard |	Upward |	LHCP
-| Left-hand |	Anti-standard |	Downward |	RHCP
-| Right-hand |	Standard |	Downward |	LHCP
+| Helices     | Feedpoint      | Radiation | Polarization |
+|-------------|----------------|-----------|--------------|
+| Left-hand   | Standard       | Upward    | RHCP         |
+| Right-hand  | Anti-standard  | Upward    | LHCP         |
+| Left-hand   | Anti-standard  | Downward  | RHCP         |
+| Right-hand  | Standard       | Downward  | LHCP         |
+
+*Source: [QHA Simulation](https://uuki.kapsi.fi/qha_simul.html)*
+
+## Schematic and Mechanical Drawing
+
+- [Schematic (PDF)](/doc/gen/QFHBAL01-schematic.pdf)
+- [Mechanical Drawing (PDF)](/doc/src/img/dimensions.png)
 
-[source](https://uuki.kapsi.fi/qha_simul.html)
+### ETC1-1-13 Transformer Specifications
 
+The **ETC1-1-13** transformer offers a 1:1 impedance ratio suitable for balanced RF transmission:
 
-### Main Parameters
+- **Frequency Range**: 4.5 - 3000 MHz
+- **Insertion Loss**: 0.32 dB typical, max 3.5 dB at high frequencies
+- **Amplitude Balance**: ±1 dB
+- **Phase Balance**: ±20°
+- **Power Rating**: 250 mW max
+- **Operating Temperature**: -55°C to +85°C
 
-  * Polarization configurations:  RHCP, LHCP
-  * Insertion Loss 2 dB
-  * Amplitude balance +/- 1 dB
-  * Phase Balance +/- 20 degree (°)
-  * Maximum RF power 250 mW (+23 dBm)
-  * Maximum DC current 30 mA
-  * Operating Temperature -55 °C to +85 °C
-  * Dimensions: 32mm diameter 20mm height (including RF connector)
-  * Weight 10 g
diff --git a/hw/sch_pcb/QFHBAL01.kicad_prl b/hw/sch_pcb/QFHBAL01.kicad_prl
index 25eea51..c25273a 100644
--- a/hw/sch_pcb/QFHBAL01.kicad_prl
+++ b/hw/sch_pcb/QFHBAL01.kicad_prl
@@ -1,7 +1,7 @@
 {
   "board": {
-    "active_layer": 41,
-    "active_layer_preset": "",
+    "active_layer": 0,
+    "active_layer_preset": "All Layers",
     "auto_track_width": true,
     "hidden_netclasses": [],
     "hidden_nets": [],
@@ -40,7 +40,6 @@
       9,
       10,
       11,
-      12,
       13,
       14,
       15,
@@ -61,7 +60,7 @@
       37,
       38
     ],
-    "visible_layers": "ffcffff_ffffffff",
+    "visible_layers": "fffffff_ffffffff",
     "zone_display_mode": 0
   },
   "git": {