Microphone Pre-Amplifier For The Irwell HF Transceiver

Back in October 2022 I posted details on the blog of a of a "High Performance AM, CW & SSB Modulator for The G6LBQ Irwell HF Transceiver" this module was somewhat experimental and for me a practical introduction to the MC1496 modulator IC. The module contained no microphone amplifier stages as it was my intention to add these as a separate module at a later date.

  To view my 2022 Modulator blog post article click here.

In this blog post I get to grips with the microphone pre-amplifier and share some of my design methods and thought processes along the way.  Note It is not my intention to provide a step-by-step guide to the design but more of an insight and reference.

The success of this module is crucial in order that I can continue development on the final transmit stages and achieve finished project status.

A VHF & UHF RF Multicoupler.

Here at the G6LBQ ham shack I have various receivers and radio scanners that I use for monitoring the VHF/UHF ham bands and other RF signals that interest me. In an ideal world each receiver would have its own dedicated antenna but that is not practical for me so I have decided to design and build an RF Multicoupler.

The main application of an RF Multicoupler is to enable multiple receivers to share a common antenna and it does this by splitting the incoming signal to a number of output ports as illustrated in the image below.

HF Transceiver VFO Microcontroller Software.

In this blog post I present an overview of the "Irwell HF Transceivers" vfo microcontroller software, it is intended as a guide to key features for those who have requested the software or are building the transceiver. 

The software and MCU hardware is responsible for generating the VFO signal, oscillator frequencies and to provide control of the various transceiver stages.

The main VFO and controller hardware is based around an affordable STM32 Bluepill microcontroller board.

A High Performance HF Transceiver RF Subsystem.

 

In this blog post I bring some of the completed "Irwell HF Transceiver" modules together and consolidate them on to a single PCB.

Summertime 2023 Catchup And A Quick Project.

 

It is hard to believe my last blog post was in February 2023 and we are now in the month of August so almost six months have past between blog posts, shame on me 😉.

During the summer months I do not tend to spend a lot of time on hobbies but now the summer is nearing the end it is time to knuckle down and make a much needed return to the blog and my Irwell HF Transceiver project.

Before I do that allow me to whaffle a little about what I have been upto in the last few months.

Modifying An Analogue Meter.

In this blog post I go all OLD SCHOOL and prepare an analogues s-meter for my  Irwell HF Transceiver project. 

Big thanks to my ham radio buddy Frank G6YAQ who kindly donated the meter for this project.

Irwell HF Transceiver Digital Modes Interface

 

My last blog post was made on the 10th July 2022 which is just a tad over four and a half months ago,  traditionaly I do not spend a lot of time during the summer months working on homebrew projects but now that autumn & winter are here it is time to melt solder again and play catch up!

Irwell HF Transceiver VFO Oscillator Module Re-Visited Pt2

For part 1 of revisiting the Digital VFO Oscillator  module click here.

 

In the last blog post I looked at replacing the three 25MHz xtals that are used for  reference clocks on the Si5351 IC's located on the the oscillator module of my digital VFO. 

The mod/upgrade to a single TCXO (temperature controlled xtal oscillator) module was carried out and tested in a lashup fashion with great success. In this blog post I report on the fabrication of a new PCB that is TCXO ready!

Irwell HF Transceiver VFO Oscillator Module Re-Visited Pt1

 

My last blog post was in February of this year (2022) and it is hard to believe we are now at the end of the month of May and close to the half way point of 2022!

I expect followers of the blog may have been left wondering if my Irwell HF Transceiver project has been abandoned but alas that is definitely not the case!

Balanced Modulator For The Irwell HF Transceiver

Before I get into the first blog post for 2022 I would like to take the opportunity to wish everyone who follows the blog a belated happy new year.

HF Transceiver - Modulator

"High Performance AM, CW & SSB Modulator For The G6LBQ Irwell HF Transceiver"

In this blog post I get to work on the the first of the transmitter modules for my Irwell HF Transceiver, a multi mode modulator that is capable of SSB, AM and CW modes.

The Cascode IF Amplifier Revisited

 For my original Cascode IF Amplifier article click here.

Cascode IF Amplifier Updates

"For The G6LBQ Irwell HF Transceiver"

Welcome to my blog post on the Cascode IF amplifier where I address a problem that I discovered with the AM de-modulator circuit and I also update the PCB to include the S-Meter electronics.

A note to self for future reference: 

"pay closer attention to manufacturers product data sheets"

Part 5 Of A Digital VFO For The G6LBQ Irwell HF Transceiver

For part 1 of the Digital VFO click here.

For part 2 of the Digital VFO click here.

For part 3 of the Digital VFO click here.

For part 4 of the Digital VFO click here.

Digital VFO I/O Expander Module

"For The G6LBQ Irwell HF Transceiver"

Welcome to part 5 of my blog post series covering the Digital VFO developed for use with my “Irwell HF Transceiver project”.

In this concluding article I present the I/O expander module which interfaces to the STM32 micro-controllers I2C bus, it's job is to extends the number of digital outputs available and provide switched logic outputs to drive my BPF and LPF transceiver modules.

Illustration of the I/O expander