Automatic CW Sender

May, the 7 2002, afternoon; just returned at home I switch-on my radio and connect to internet to make some search;
on the cluster there is an interesting spot: K1B - 21Mhz - CW:  with the VFO set at 21.025 I continue with my internet search, but K1B signal is very strong: "today is possible" - I say - " I just need to spent 5 minutes calling and searching for the right split";
time to time I try calling, but I must temporarily stop my work:
The best will be to have a CW keyer transmiting the full callsign with a simple push.

So here is ACWS: a simple circuit that, with a  simple push, transmit a memorized Cw message;
I know that today with a simple PIC, you can do the same and better, but my project was to use only old components in my shack.

It works at the following way: the eprom contains various CW messages as a sequence of 0 and 1; the CD4040 addresses the eprom wich give as output a sequence of 0 and 1; it's necessary to associate
a dot to 1,
a line to three 1,
a space (in a character) to 0,
a space between character to three 0,
a space between word to five 0.
For example the word "CQ" became

C (space) Q
- . -.   - - . -
11101011101 000 1110111010111

We know the eprom have 8 bit (8 output) so it's possible to associate each output to a message; in my own I've used the eprom to memorize 4 messages: one output is used to contain the message, the following as control line (as start-end indicator);
I've used only the first two messages (I just needed
  "IZ7ATH" and "IZ7ATH 599 BK"); If needed it's possible to have more messages simply using a switch or dividing the eprom address (bank 1 from address  0 to 1000, bank 2 from 1001 to 2001 etc.).
You can also use more control line (for example in a FM repetitor control).



CD4011 is a double flip flop while CD4066 switch the right output to PTT:
pushing the key "MSG1" , the output of flip-flop 1 goes high, transistor Q1 opens, grounding pin11 (CD4040) so CD4040 can count (and the eprom gives the messages as output);
at the same time all the eprom output goes to the CD4066 but only the selected one pass on (thanks to the flip-flop output that enable only the right switch);
at this point all bit of the control line (associated to MSG1) are 1 (+5v); at the end of message this line goes low (0) resetting the flip-flop;
for example the word  "CQ" will be memorized as follows:


MSG C (space) Q  
D0 11101011101 000 1110111010111 0
D1 11111111111 111 11111111111 0


Will be better to have the same clock signal (Cw speed) for the CD4040 from the CW keyer, but in my case that was not possible so I've used a simple CD4001 as clock generator; I've used a double variable resistor: one section to change the speed of  ACWS, the other for the keyer; in this way I can transmit messages at the same speed of the keyer.


Messages are memorized in a 27C74 eprom (a 2716 will be enought) using Kisseprom (my eprom programmer);
I've also written a simple Visual Basic software to generate the eprom file.




CLICK HERE TO DOWNLOAD ACWS.ZIP (the software and the source code)




73 de iz7ath, Talino Tribuzio