Posts Tagged ‘home-brew interference’
Morsemail and LCWO.net
The time has come when I can’t put off learning Morse code any longer, With an interest in vintage amateur radio and the impending restoration of a Heathkit AT-1 I’m going to need to use CW sooner or later.
So I have been checking out resources for learning Morse code and stumbled across two that really intrigue me.
The first is LCWO.net, a web browser based Morse code learning tool that is usable on any internet connected computer. It is available free of charge and there is no software to install. LCWO.net keeps track of where you are in your lessons and where you need to concentrate your effort. The Koch method is the primary tool available but they also offer code group practice, callsign and plain text training modes along with a service to convert text to Morse MP3s for download and use offline.
Once you are on the way to CW proficiency and want to communicate with others you can always fire up a rig and get on the air … What if you don’t have a rig or need a confidence boost before ‘going live’?
Well, you could always send Morsemail using the Morsemail client from http://brasspounder.com:8873/.
Morsemail is, “A simple text format that encodes mark and space times to make it possible to send Morse coded messages via email” but a recently added feature allows for QSOs using a internet repeater hosted on brasspounder.com. You can use a mouse or actual key wired to the mouse or joystick buttons to send CW which can be emailed or sent through the repeater live.
Now I just have to carve out the time to sit down and use these resources!
Hellschreiber and microprocessors – Bridging more than 80 years
ZL1HIT (Bryan Rentoul) has bridged a gap of more than 80 years by combining the text transmission system developed by Rudolf Hell in the late 1920’s with current microprocessor technology.
|A sample of received Hellschreiber test from Bryan’s beacon|
Hellschreiber sends a line of text as a series of vertical columns. Each column is broken down vertically into a series of pixels, normally using a 7 by 7 pixel grid to represent characters. The data for a line is then sent as a series of on-off signals to the receiver, using a variety of formats depending on the medium, but normally at a rate of 112.5 baud.
This process was historically accomplished with mechanical equipment but there are very few examples of this equipment still in operation and it is now sent and received by computer. Hellschreiber is very tolerant of noise and interference and requires only simple transmitters and receivers to work effectively.
|German Hellschreiber unit in operation|
With a microprocessor generating the digital on-off signals a simple crystal oscillator transmitter can be used to form a beacon station, one that transmits a call sign and perhaps some other information over and over. Changing the transmitted message is as simple as reprogramming the microprocessor or having it respond to a connected input, for Eg. A thermometer, light sensor, switch, etc.
Receiving the signal and decoding requires a radio receiver capable of CW reception and a computer running any of several free software packages like FLdigi or Digital Master 780.
|The ZL1HIT beacon using a PIC microprocessor and a simple crystal oscillator transmitter.|
For more information and the PIC microprocessor source code please visit the web page of Bryan Rentoul here : ZL1HIT Hellschreiber / PIC Beacon