Update README

1 files changed, 22 insertions, 11 deletions

diff --git a/README.md b/README.md
index 7ab6f86..bf30d8d 100644
--- a/README.md
+++ b/README.md
@@ -10,19 +10,19 @@ The hardware design is licenced under the "CERN Open Hardware Licence Version 2
 The firmware is MIT-licenced.
 
 * Designed in KiCad
-* Meant to be used with a microwave transverter
-  * But also stand-alone 144MHz
-  * Offer plug-in band-filters for other HF bands
+* Meant to be used with a microwave transverter and stand-alone 144MHz
+  * For transverter usage, no PA reduces current consumption.
+  * For stand-alone, see MMRF1021 amplifier below.
 * Using a STM32F103C8T6 controller
   * Programmed in [Rust](https://rust-lang.org/)
-  * Si5351 clock source (generates  clocks)
+  * Si5351 clock source (generates HF clocks)
   * An LCD display
 * Discarded ideas
   * Include a Lars Widenius GPSDO originally published on [eevblog](https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/?all)
   * Offer a 10MHz output refclk for a transverter
-  * Instead, have a 25MHz ref input, and use a LeoBodnar reference
+  * Instead, have a 25MHz ref input, and use an external reference
   * Use the Si5351 to generate the VHF LO at 116 MHz
-  * It wasn't clean enough, so a separate [XTAL LO board](./lo_board/) was designed
+    * It wasn't clean enough, so a separate [XTAL LO board](./lo_board/) was designed
     * With a 114.286 MHz crystal, we get a first IF of 29714 kHz
 
 *First QSO done with this transceiver and MMRF1021 amplifier on 2020-12-07*
@@ -31,6 +31,14 @@ On RX, an [LNA4ALL](http://lna4all.blogspot.com/) LNA was used. On TX, 2x SPF518
 and the [MMRF1021](http://git.mpb.li/git/mmrf1021-pa/about/) amplifier were used, giving about 200mW output power on the
 very first trial.
 
+Later, the external bandpass and 2x SPF5189Z were replaced by an internal bandpass with less insertion loss and a single
+SPF5189Z.
+
+TODO
+====
+
+* Where does the 1.6kHz offset come from?
+
 Open questions
 ==============
 
@@ -61,7 +69,11 @@ Issues
 * 2m LPF from LimeRFE use values I don't stash
   * 20pF done with 2x 10pF
 * SW: ADC input for buttons looks messed up...
+  * Four buttons instead of 7 are enough anyway
 * Connect 3V3 LDO to 12V directly
+* Also, replace DCDC by L7808 to improve spectral purity
+  * Actually there would be more to be gained with a DCDC on 5V or 3V3!
+* Added a LM360T LDO for the MMRF1021 so that it can be powered from 3S LiPo (11.1V) and Pb (13.8V) batteries
 * Add 2.2uF caps near consumers
   * Replace C535, C536
   * Replace C343, C315
@@ -73,9 +85,9 @@ Issues
   * Next to R504
   * Next to R328
   * Next to R515
-  * I still have spurious next to transmit frequency, spaced 200kHz because of the DCDC converter
-  * Measure 8V current!
-* Added 100nF caps on microphone connector to suppress RF being coupled
+* Reduce RF coupling
+  * Added 100pF caps on microphone connector and CW input
+  * Added 22pF on DC jack, DIN
 
 PCB Assembly Plan
 =================
@@ -140,7 +152,6 @@ Si5153 test before PCB fab:
   * clk1: VHF-LO = 144 + 28 and 144 - 28, i.e. 116 MHz
   * clk2: BFO = 4.91521
   * See `freqplan.py`
-* If not, generate LO1 and BFO with Si5153, and connect an external LO to the VHF LO u.FL
+* This ended up being too noisy and was replaced by an external VHF LO, with LO1 and BFO generated with Si5153
   * No 116MHz crystals on mouser, but 114.285MHz are available, HF bandpass filters recalculated.
-  * Other option is using another configurable reference