G4AKW

# Simple Tkinter GUI for G4AKW Morse Program # Geoff Robinson Dec 2011 # Version 1.1 from Tkinter import * ''' This differs from the traditional import statement in that it puts everything in the module into the default namespace of this program, so now rather than needing to refer to a textbox as Tkinter.Textbox we can just write Textbox ''' import tkSimpleDialog as tks import tkMessageBox root = Tk() # window geometry is width x height + x_offset + y_offset root.geometry("600x160+350+300") root.title('G4AKW Morse Program') Label(root, text='Enter code to send in box').pack(pady=10) # Left frame to hold buttons left = Frame(root) left.pack(side=LEFT, expand=True, fill=Y) # Right frame to hold display right = Frame(root, height=100, width=300, bd=3, relief=GROOVE) right.pack(expand=True, fill=BOTH) # change the colour of the right-hand frame def changeColour(c):     def change():         right.confi...

  #!/usr/bin/python """ Morse Code Generator. Geoff Robinson, G4AKW, Version 1.0, 4th December 2011. Requirements: Python 2.7, Linux OS, alsaaudio. Usage # python mainmorse.py The basic element of Morse code is the dot and all other elements can be defined in terms of multiples of the dot length. The word PARIS is used because this is the length of a typical word in English plain text, it has a total length of 50 dot lengths. If the word PARIS is sent ten times in a minute using normal Morse code timing then the code speed is 10 WPM. There are 500 dot lengths in a minute for 10 wpm or 1000 dot lengths per min for 20 wpm. The dot length is therefore 60mS for 20 wpm. The python dictionary 'code' and the function convert() converts characters to their dot space equivalents i.e either on or off keying. """ import serial import time, thread import random import sys import sched import wave, struct, math from alsaaudio import * impor...

The first steps in restoring and updating the old G2DAF linear amplifier commenced with the removal of the 2 x 6U4GT rectifier valves and the associated voltage doubler components / 300 ohm input circuit. This will be replaced with a solid state voltage doubler (probably a 1N4148 diode stack) and a 1:4 unun broadband transformer to give as close a match to 50 ohms as possible. Next step was to solder a 5000 ohm resistor from the 813 anodes to ground. Two 10k resistors in parallel were used (see photo) to represent the load that the valves should see under normal operation. An MFJ antenna analyser was then connected to the pi - tank output and the variable capacitors in the tank circuit altered until a 1:1 50 ohm match was obtained on 80m and on 10m. This checked  the output matching circuit.

This antenna is a dipole, each leg approximately 60 ft long (overall length ~ 120ft), fed with open wire feeder (ladder line).  Photo 1 shows the ladder line (constructed from plastic garden plant staples garden centre stuff is usually good at withstanding the outdoor conditions!), and the feed point insulator. A short length of 12 guage wire is used to take the wire tension and support the ladderline on each side of the insulator. The ladder line spacing, around 3 inches in this case, and its characteristic impedance, approximately 500 ohms here, is not important. (Spacing determines the maximum power handling capability (volts) and wire thickness (current)). The ladder line enters the house and is connected directly to the transmatch by two lengths of URM 67 coax stripped of its outer sheath and braid (photo 2).  These two 2 ft lengths take the feedline through two 15mm speed fit Polyethylene pipes through the wall and into the living room.  The impedance at the point ...