2N2/40 CW Transceiver - Part 1 - Introduction

Compiled and Edited by: O. Alan Jones, N8WQ

After over one year of procrastination (MARCH 2023), I finally got started on my build for the 2N2/40 CW Transceiver which was designed and built by Jim Kortge K8IQY.

https://www.k8iqy.com/qrprigs/2n240/2n240page.html

If you have not read Jim's article, you really should, it is a treasure trove of information. https://www.k8iqy.com/qrprigs/2n240/K8IQYs%20Original%202N2-40%20Article.pdf

I officially kicked off my adventure on March 10, 2025 and began to collate all the documentation I could find on the 2N2/40 transceiver.

Besides Jim's original article, you will also need to read the Winter 1998 Edition of the QRPp Journal of the Northern California QRP Club, Vol. V1, No. 4.  The article entitled "2N2/40 40M CW "Built It From Scratch" Transceiver, is found on pages 4-49.

The 2N2/40 is built in a sequence of steps:

T-R, SEQ 1 - RX/TX Driver, page 17

VFO, SEQ 2 - Varicap Tuned VFO, page 19

FE, SEQ 3 - Receiver "Front End", page 23

IF, SEQ 4 - Crystal Filter/IF Amp, page 25

DET, SEQ 5 - RX LO Oscillator and Product Detector, page 43

AUD, SEQ 6 - Receiver Mute and Audio Amplifier, page 31

TX, SEQ 7 - TX Local Oscillator, Mixer & Amplifier, page 35

PA, SEQ 8 - Transmit RF Driver, Power Amplifier & Output Filter, page 37

 

The BOM is found on pages 40 and 41 of Winter QRPp 1998.

 

I created my own parts list for each stage/sequence of the transceiver in Excel. I verified all part designators by comparing the schematics to Paul Harden's (NA5N) excellent drawings and the BOM. For my build of this transceiver the schematics will have priority though :)

 

I will continue this discussion in 2N2/40 CW Transceiver - Part 2 - Layout of Substrate

 

73,

O. Alan Jones, N8WQ

 

 

 

 

1Watter & 5 Watter Keyer Circuit by W8DIZ

After I posted my request for a favorite electronic keyer circuit on qrptech@groups.io, my friend Bill K6WHP reminded me that the 1 Watter & 5 Watter transceivers used a nice keyer circuit.

Diz W8DIZ designed his keyer circuit around the ATTINY45 microcontroller.

I robbed the keyer chip from my 1 Watter 30M Transceiver for this experiment. I decided to build this circuit using the manhattan construction style technique. 

I took my time and built this circuit over several evenings spending 15 or 20 minutes per session. A college professor once told my class that "Sometimes the journey is more important than the destination." It is fun to build and learn new things and to stop and think along the way.

The keyer works great and I like the iambic B mode the best. I used my favorite LM386 circuit for my amplifier, but I plan on building a discrete amplifier for it just to be different and to learn something new. If you have any favorite discrete amplifier circuits please let me know!

In conclusion, I need to connect the keyer to one of my transceivers and make sure that it will key the transmitter. Give this keyer circuit a try and let me know what you think.

73 for now...

N8WQ

PMK Keyer from Midnight Design Solutions

 

This is my build of the PMK Keyer.

On July 7th of this year I posted on qrptech@groups.io a message that I was in the mood for building a keyer and I asked for favorite circuits from everyone. No one mentioned the PMK Keyer from Midnight Design Solutions. While I was looking up keyer circuits I found this circuit design by Dave Benson K1SWL. I already had three Picos in stock in my junk box, so I went ahead and ordered the pcb along with some prototype boards and headers for experimenting with the Raspberry Pi Pico. George Heron N2APB kindly included a BOM to order all the parts from Mouser on his web site. That saved me a lot of time! 

https://midnightdesignsolutions.com/pmk/

The hardest part of this build for me was getting the right female headers installed for the Pico on the PMK pcb. At first I used some headers from Adafruit, but they were not tall enough and the soldered male pin headers on the Pico were not going deep enough into the female headers. Luckily, I have a Hako FR-301 de-soldering gun and I was able to desolder the Adafruit female headers with no problem. Next time I will be more careful and do better planning! :)

Building the PMK keyer went smoothly and the only confusion I had was with the Setup mode and Operational mode of the keyer. I asked George some questions and he was able to give me the information I needed to understand how everything worked.

PMK discussion, news and support are available at https://groups.io/g/cwtd

This is a nice keyer and for me it was a easy build. The firmware is written in MMBasic and for me it is easier to understand than MicroPython. Using a terminal program called Tera Term to access the firmware and to Setup the keyer had a cool retro vibe!

I want to thank George and Dave for making this keyer available. Now I am motivated to see what other projects I can come up with using the Raspberry Pi Pico!

73,

Chaplain O. Alan Jones, USA Retired

N8WQ

NorCal 80/40/20A Transceiver Build Project

 

Sorting Parts for Power Supply Stage

Back in 2017 I built a NorCal 40A Transceiver using a beta pcb that was given to me. My transceiver works but I was never happy with its performance. So I decided to build another 40A, 80A, and 20A in unison as a learning experience and to have fun! I am using the NorCal 40A Revision 2.0 pcb that is archived on the qrptech@groups.io forum in the Files section.

This is my test jig I use for building stuff.

Back in May of 2019 I decided to build a test jig to make it more user friendly when testing the circuits I built. A few days ago I added a homebrew audio amp module so I don't have to tie up another audio amplifier in the shack.

Power Supply and Audio stages pass the testing phase. 

This is my NorCal 40A pcb.

The next stage to build is the AGC and Mute circuits.

More to follow...

August 13, 2021

Alan Jones

N8WQ

Color Code Charts

Recently I discovered a web site that is really cool. It is called AmericanRadioHistory.com. I was reading the 1970 issue of Electronics Installation & Servicing Handbook when I stumbled onto this color code chart that I thought I would share.

https://www.americanradiohistory.com/Archive-Hobbyist-Specials/Electronics-Installation-Servicing-Handbook-1970.pdf

Go to page six and you will find a Color Code Chart. I printed a copy to put in a binder that I keep in my lab called Construction Techniques. The older I get the more I tend to forget things and the binder is a great way to keep important information at my finger tips.

73,
Alan Jones
N8WQ

Going Digital - Journal of Power Management

Thanks to the rain yesterday, by the time I made it out to my mailbox, my paper copy of the Journal of Power Management was wet. Immediately I tried to pull apart carefully the pages before they got stuck. I ended up pulling out both staples and scattered each page around my living room to dry. This morning, as I was puting the dry journal back together, I noticed on page two the following:

"To reduce paper use, Power by Linear Journal is going digital and will no longer be regularly delivered as a printed publication. To ensure that you receive electronic delivery of the latest Journal to your email inbox, check your MyAnalog account. Make sure you have checked "Power by Linear" under the "Resources > Newsletters" in the settings for your account."

Go to www.analog.com to update your free subscription.

Design First--Build Second

IF Amplifier Test Build

During the month of November I stumbled onto a Youtube channel run by Charlie Morris ZL2CTM. I was immediately impressed with Charlie's build philosophy: plan your circuit, consult datasheets, do the math, build and test!

Towards the end of Spring 2018, I got the bright idea of building a rig from scratch and making it a summer project. But I quickly got bogged down in the design phase of my project. I never made it past the local oscillator! :)

Thanks to Charlie's excellent teaching skills, I now have a road map that I can follow on future projects. Head over to Charlie's channel and see what he is up to. 

https://www.youtube.com/channel/UCSNPW3_gzuMJcX_ErBZTv2g

Right now I am five stages behind on his "Homebrew MC1350P based SSB Rig" and my next step is to build the RF Amplifier stage. But before I do that I am thinking about building the "8640-Jr Test Oscillator" that I never got around to building in the Fall of 2015.

73,

Alan Jones, N8WQ