Microwave Morse Code and Tone Generator
David Wrigley, G6GXK

Overview
This Morse Code and Tone Generator has been designed for use with a Microwave Transverter.  Its function is to aid the identification of stations and for antenna alignment in Narrow Band activity.  It is a significant improvement over the author's previous method of holding a DTMF Tone Dialler in front of the Microphone.

The four functions contained within this design are accessible by means of a four way panel mounted switch.  

1. Microphone and PTT (normal transverter operation)
2. Continuous Tone output for setting up antennae, WG matching, Horn feeds and other measurements etc
3. Morse Code ID every 10 seconds - can be left on for others to find.
4. Warble tone - very distinctive as an alternative to Morse Code for others to initially find the frequency and/or direction of the station.
A red LED on the front of the unit shows when the tone is being output and flashes with the code sent.  This also acts as reminder that the unit is transmitting.  This LED output can also be used to drive a transistor switch as a CW key output for the Morse code enthusiasts.

Design
The unit is based on PIC16C84 4MHz DIL Package this is plugged into a DIL socket so that an alternatively programmed or updated chip may be inserted at any time.   For those not familiar with this chip - it is quite a few years old now- it is a complete computer on a chip with EEPROM included.  The program uses a counter timed interrupt routine to provide the frequency of the tones.  The dots and dashes are made up of binary bits.  One bit "1" equals one dot, three bits "111" equals one dash, one zero "0" equals space within a character three zeros "000" equals space between characters etc.  The required code to be sent is stored as a string of ones and zeros stored in the memory and retrieved one by one by the program and used to enable or disable the tone output.  The output audio is in fact a square wave which is rounded off a bit with an RC filter and set to a suitable level for the FT290 by means of a built-in attenuator.  The unit plugs into the Mic line of the FT290 and Socket wiring information is  provided for this.  Of course the wiring and attenuator levels can be modified for other transceiver types.
Programming the chip.  The loading of the program is easily carried out with a simple home built programmer attached to the printer port of a PC.  The sequence of events is as follows.

1. Using a text editor such as "Notepad" in Windows make any changes to the program that you require. (I use Programmers File Editor which has a few more bells and whistles but results in the same thing at the end).  Note that you will need to insert your own call sign/locator or other message into the program.  The resulting source file must end in ".asm" but the file name itself can be made anything you like as long as you can remember what it is.
2. Use an assembler to convert the text file into a file recognisable by the programmer (and by programmer I mean that device and its operating software which is going to load the program into the chip). I use MPASM for windows (mpasmwin.exe) downloadable as a zip file from Arizona Microchip website which is a link from David Tait's Site (Ref 1).  The assembled file ends with the extension .hex since it is basically a hex file of what we want in memory plus some other information recognised by the programmer.  If you want more information on the assembler language or the chip specification/instruction set,  it's all there at the Arizona Microchip site.
3. Assuming that the programmer is connected to the PC, move the assembled (hex) file into the same directory as the programmer and run the programmer. I use a batch file to do this which is "pp tone8.hex" where "pp.exe" is the programmmer software and "tone8.hex" is the assembled program.  The programmer hardware details are downloadable from ref 1 and it's fairly easy to build one up on a piece of VERO board.  Programmer kits with a PCB are available at most UK radio rallies - look for the D2MAC satellite card stalls - a similar processor is also used in the decoder cards but you need the PIC chip programmer and not a card programmer.  On the same stalls they usually sell the PIC16C84-04 DIL chips for 2 or 3 GBP each.  The programmer software by David Tait is currently at rev 05 and this now also works with Pentium PC's (earlier rev's had problems with the printer port on some Pentiums).  I have red and green LED's on the programmer so that I can watch the process - it usually takes only a couple of seconds or so and a message should come up on the screen to inform the user of the success or failure of the operation.  Failure can be that you put the chip in the wrong way round  - I did that once and amazingly it survived to be reprogrammed and is still working well.
4. Of course you may not be into programming or PC's - but there is usually some radio amateur in your locality with suitable equipment to do it for you.  It only takes a few minutes.  It takes longer for Windows to load than to program one of these chips!
Construction
The printed circuit board contains most of the components and is designed to be mounted on the rear of the screwed rods which hold together the rotary panel mounted switch (the prototype used a Maplin type).  In the author's case the LED was mounted on the panel above the switch and two sockets were mounted below the switch.  Make sure that the PCB is mounted so that the PIC device points to the rear and is easy the extract and replace when in situ.

List of files contained in the distributed zip file
1628text.doc					Word6 version of this file
1628TEXT.txt 					Txt version of this file(poor format)
1628-PCB.gif 					PCB Layout
1628-cct.gif 					Circuit Diagram
tone8.asm						Software source code
1628assy.gif					Component assy diagram	


Acknowledgements, Conclusions and Future DevelopmentsThis design is the result of a mixture of sources, principally from a program written by GW6BWX (1998) and published by the British Amateur Television Club but I must mention the work of Gary C Sutcliffe W9XT who published a design for the PIC16C54 in 1995.  There is no problem with making these units for ones own use but commercial rights are specifically not granted. All copyright matters reserved.The present package is the current state of development and is as usual a constantly moving target.  Some recent minor changes have been made to the documentation just prior to issue and a further prototype has not yet been built precisely to this latest issue.  It is therefore possible that an error has crept in. Please let me know by Email to david.wrigley@umist.ac.uk  if anyone finds something inconsistent, wrong or incomprehensible.  I will do my best to help.  I have been working on some future ideas as follows and they are simply waiting of the time to complete them.

1. The addition of automatic Morse code ID every 15 Minutes on all positions to avoid inadvertently breaching the Radio Regulations.
2. Addition of components on the pcb to give key output directly.
3. Changes to the available alternative tones to suit user requirements.
4. Addition of a 10 second digital voice recorder chip to permit voice rather than Morse code ID.



References
Ref 1	David Tait's web site  http://www.man.ac.uk/~mbhstdj/piclinks.html  This is probably the best site for PIC info and links. Ref 2	British Amateur Television Club (BATC) web sit - this is a good web site and one to which I gladly subscribe.  There is plenty of interesting information and software to download.  Take care, you might get addicted to ATV!  http://www.batc.org.uk
Ref 3 Author can be contacted by Email to david.wrigley@umist.ac.uk in case of difficulty or errors




Later Revisions
The original PCB layout had a serious error on it (one side of xtal not connected and relevant IC pin grounded) This has now been corrected in rev 03 of the artwork file dated 19991023  (23 Oct 99).  The symptom which this produced was that there was no crystal oscillation at all - If the waveform on pin15 of the IC is checked on a CRO, it should be 2 volts peak to peak at 4MHz. This will confirm that the PIC chip clock is working - the clock will at least give the processor a chance to operate - without the clock there is no possibility of it working.

Some changes and corrections have also been made to the assembler file - see history on file.

A further, cut down circuit is given, using the same layout.  This will enable a beacon to be keyed (fsk) by applying the attenuated output voltage swing to a varactor across the beacon's frequency determining xtal. This has been used to key the butler oscillator of a DDK004 board feeding a WDG001 multiplier and a 250mW power amplifier for a 10368MHz beacon.

ref: David Taits web site is no longer managed by David Tait and the archives have been moved to another location - instructions for building a programmer are on my own web site - see PIC and Computer section

16F84 now used instead of 16C84.

The revised distributed files list is now (cwid-03c):

1628-cct.gif 					original cct diagram
19991023 components.bmp				revised component layout
19991026 rev03B artwork.bmp			revised copper track 
(NB this is horizontally flipped and is suitable for iron-on transfer)
19991026 composite view.bmp			view of the components and the track
19991023 PIC ID beacon version cct B.bmp	cut down cct for beacon use
20001222-text.doc					supporting text in "Word" format
20001222-text.txt					supporting text in "Notebook format"
Tone8b.asm						Software 

