My Third Modification

Since learning Morse code is a slow process (for me anyway), I decided to use the "CW Type" software to send Morse code. That required to somehow connect the Pixie transceiver to the computer. My computer does not have a serial port and I did not want to mess around with USB to Serial adapters. Therefore, I designed a small circuit that activates the key (PTT) of the Pixie transceiver using the soundcard speaker output of the computer. Here is the circuit:

The Soundcard to PTT (or key) interface. It works really well even with the low output levels of the headphone connector of my smartphone.

Here is the layout of a printed circuit board:

Printed Circuit Board (PCB) layout

Position of parts on the PCB

I was too lazy to etch a PCB and decided to build the circuit the ugly way. Really the circuit is so simple that a PCB is not really necessary:

My soundcard to Pixie PTT (key) interface. I did not go through the process of etching the PCB shown above.

The circuit works really well. Now I can use the "CW Type" software to send Morse Code with my Pixie transceiver. The next step will be to fit both the pixie and the soundcard interface in an Altoid box.

The Pixie Net

I would love to setup a Pixie Transceiver Amateur Radio Net for operators that use the Pixie Transceiver. We could decide on a regular day and time and crystal frequency and then all meet at the same time using the same frequency for a formal amateur radio net for Pixie Transceivers only. This link explains amateur radio nets:
https://en.wikipedia.org/wiki/Amateur_radio_net
If you are interested in this idea, please e-mail me. I am in Iowa City, IA. So if you are in the Midwest, we should be able to communicate using the Pixie Transceivers. I am looking forward hearing from you.

Decoding Morse Code

I found it rather difficult to learn Morse code. So I searched for a software that decodes Morse code.

The best CW decoder software that I found was "CW Skimmer" that can be obtained from:

http://www.dxatlas.com/cwskimmer/
This is an excellent software and it is probably justified that it is not free software. It costs $75. I think it is worth that money. But I wanted a free alternative and kept looking for free CW decoder software and I could not find anything that was nearly as good as CW Skimmer. So I decided to write my own software for Windows. So far, I have a beta version that is not nearly as good as CW Skimmer but it works reasonably well for me. Here is a link to my free CW decoder software if you want to give it a try:
My CW Decoder Software
This link is to a ZIP archive that contains installation files for 32-bit and 64-bit Windows systems. If you test this software, I would love to hear back from you for suggestions to improve the software. Unfortunately, I have not written a Manual yet. But that's on the ToDo list.



My CW Decoder Software

It decodes the full audio spectrum up to 22 kHz, which is interesting when using the Pixie Transceiver, because this transceiver has a very open front end and you can see multiple CW stations in the full audio range up to 22 kHz.

For sending Morse code I use the free "CW Type" software. I found this software to be excellent. It can be obtained from:
http://www.dxsoft.com/en/products/cwtype/

My Second Modification

The kit is fairly easy to solder together and it worked right away when I first powered it up. For an antenna, I just connected a long random wire that I routed out of my window and into the backyard.
However, a major issue was that the audio signal consisted mainly of local broadcast radio stations that covered all the CW signals that I was after. I figured that the broadcast radio stations were entering the transmitter through my random wire antenna. The output filter of the Pixie to which the antenna is connected, is just a low-pass filter that allows all lower frequencies, including AM radio stations to pass into the Pixie. Thus, I decided to replace the output filter with a band-pass filter for the 40M band. I came up with the following design:


A band-pass filter for the 40M Pixie Transceiver

It is fairly easy to switch the standard low-pass filter with this filter by replacing the two capacitors and the inductor of the original circuit with the LC combinations shown in the circuit above. Here is how this looks on my circuit board:



I replaced the original low-pass filter with a band-pass filter.

After this modification, all the broadcast radio stations were gone and I could clearly hear the CW stations. On transmit, I still get the full output power of about 1 Watt when operated with a 13.8V power supply (measured using the MFJ-813 QRP SWR Wattmeter). Now I had a working 40M CW transceiver and could start learning Morse code ...

My First Modification

Unfortunately, the Chinese Pixie Transceiver kits come with a crystal for 7023 kHz, a frequency on which Technicians are not allowed to operate. Thus, I ordered a set of crystals with frequencies that I was actually allowed to use. In addition to the 7023 that I am not allowed to use, I now got crystals at the following frequencies: 7028, 7030, 7040, 7047.5, 7050, 7114, 7122 kHz. Now I needed a way to switch crystals. Thus, instead of soldering the crystal directly on the printed circuit board, I inserted a socket that allowed me to switch crystals.


Instead of the crystal, I soldered in a socket that allows to switch the crystals (red circle).

The Pixie Transceiver

After receiving my Technician Ham Radio License in 2012, I only used a Boafeng UV-3R VHF/UHF handheld transceiver. While listening and chatting on the local receivers was somewhat fun, I was looking for more technical challenges. The Technician License allows CW operation on the 80M, 40M, 15M, 6M, and 2M bands. Thus, I needed a CW transceiver. A quick search on eBay resulted in a Chinese Transceiver Kit that operates on the 40M band for less than $5.00. This seemed to be such a bargain that I ordered three of the kits.

The Chinese Pixie Transceiver Kit