Mark-World - Tech Projects To Amuse The Curious
Ham radio is very much alive these days and has added to it's traditional modes of transmission a great many digital mode over the airwaves modes involving computers, compressed audio, digital signal processing and even video.   

For me Ham Radio is a field that merges the physical world of antenna and propigation with the electrical and more and more every year the microcontroller aspects of my hobbies.

At this time due to small number of projects I will present my Ham Radio projects on this one page.   This page will frequently drop into the 'lingo' of Ham Radio and is not meant to be useful to those who are not familiear with Ham Radio.
WSPR Transmitter Station
CW Keyer Practicing Rig
WSPR or Weak Signal Propagation Reporter is a network of a great many private Ham operators that each run a typically low power transmitter that is periodically every 5 minutes or so transmitting a beacon that contains the location and power of transmission.   This is then picked up by any number of receivers that remotely recieve the signal and report it to an internet database.   This allows evaluation in near real time of signal propigation properties for different ham bands.

Below is my WSPR station which transmits at 2 watts from time to time and has at it's core a Raspberry Pi 3 running a modified version of the Wsperry code that includes a few of my own home brew tweeks to allow managment of this node. 
This is an Arduino Nano based project that I put together using very popular software for a 'CW Keyer'.   So besides assembly and a custom 3D printed case and 'product design' I did not have to do much at all to get this going except make it look nice.

Look for the K3NG Keyer Arduino Code To Start On One!
The 7MHZ  7th-order Butterworth Filter (Required)

A sharp cutoff 7mhz filter with custom wound coils seen in this picture was also required to make raspberry Pi digital square wave signal be suitable for broadcast usage. 
Some Key Info For Makers: 
- Raspberry Pi 3, first version.  Chipset matters it seems.
- Filter GPIO with 7-pole butterworth filter
- 3W  RF amp is 2Mhz-700mhz 12V on EBay for $10
- CodeBase:
- The project box is a PolyCase XR-34F

Ham Radio