From 3c699a144cecbdd873f9f038f17572b32f5a7437 Mon Sep 17 00:00:00 2001 From: "Matthias P. Braendli" Date: Sun, 24 Jan 2021 13:46:52 +0100 Subject: Update README --- README.md | 33 ++++++++++++++++++++++----------- 1 file changed, 22 insertions(+), 11 deletions(-) (limited to 'README.md') 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 -- cgit v1.2.3