arrange skeds,
meet other CCW operators, and
discuss aspects of CCW.
PCW is a Coherent CW program which uses the Sound Blaster, and has useful features like auto tuning, self synchronisation, and auto threshold level. Coherent CW is normal morse code with very good timing and frequency accuracy, so you can use 20Hz filters and integrators to get remarkable results from very week signals. Click here for more info on Coherent CW.
Precision CW, (PCW) V2.1 (Shareware Version) by Ernst Schroeder , DJ7HS, is now available Here.
I have set up an email reflector on ONElist for Coherent CW. The list name is "Coherent_CW" in the recreation.radio group.
I have set up the list so that CCW operators and those interested in trying CCW can:
arrange skeds,
meet other CCW operators, and
discuss aspects of CCW.
If you would like to receive emails from other interested CCW operators on this reflector you should subscribe to the list, it's FREE, and I doubt there will be too much traffic. ONElist screens spamers so you shouldn't get any junk mail. If you subscribe to the list then if anyone is interested in a CCW sked they only have to send an email to the list and you and all other CCW operators on the list will get a copy. It couldn't be easier to arrange a CCW sked! But it only works if people subscribe, so do it now! You can get off the list at any time.
It would be great to see some public discussion of CCW too, so others can see what's going on and can join in.
To subscribe to the list, goto ONElist http://www.onelist.com, and register. You need to be registered to subscribe to any ONElist mailing lists, but you can view old messages from the web site without registering. The advantage of this arrangement is that they can virtually eliminate junkmail this way.
Once you have registered on ONElist, subscribe to the Coherent_CW list by entering "Coherent_CW" in the search field on the home page, along with your registration details in the spaces provided, and do a search. When you find the list you will be given the option to subscribe to it. You can remove yourself from the list and change options etc from the "Member Center", just enter your registration details and press "Member Center" on the home page.
You'll get instructions on how to use the list, and you will need to confirm your email address by replying to a confirmation email ONElist sends automaticly when you first register.
To send an email to the list just send an email to Coherent_CW@onelist.com once you have registered.
PCW requires a Soundblaster compatible sound card that works under DOS. The BLASTER enviroment variable must be set up correctly. If this is OK, then PCW should work. You will need to connect the reciever audio to the sound card input and for TX you will need to make a simple CW keyer unit. This is the same as the Hamcomm PTT interface - RTS of selected COM port is active HIGH, ie HIGH voltage = key down. With most modern rigs you only need an NPN general purpose small signal transistor, eg 2N2222 or BC547, with emitter connected to the common ground, collector connected to the KEY input, and base connected to RTS through a series resistor of about 10k.
To configure PCW there are a number of command line options, these allow you to set the COM port, keyboard type, Soundblaster input, select the sound card, and even set your prefered operating settings at startup such as speed etc.
Various example command lines are given in various batch files in the ZIP file. An example command line would be:
pcw.exe com2 sb+ line+
This runs PCW with COM2 for TX, Soundblaster for RX, and using the line input on the sound blaster (MIC = default). Look in the help for other command line options.
Press CTRL-F9 to confirm that everything is working properly, it should show COM port and soundblaster information.
Firstly, CCW DOES NOT WORK on normal CW, since it required perfect timing to work. It will only receive proper CCW transmissions.
To receive a CCW signal you should tune the RX so the audio tone is within 20Hz or less of the frequency shown in the top right corner on the screen. When the audio freqency is close enough a difference frequency is given (dF), so you can fine tune your receiver to the right frequency. To fine tune the signal use ALT-F1 and ALT-F2. This change the frequency shown on the screen. Alternatively, the Auto Tune feature will automatically fine tune the signal.
Start with a wide bandwidth, this makes tuning easier. Reduce the bandwidth once you are tuned in to improve sensitivity.
Let the Autotrack function follow the timing of the incoming CCW. (Make sure Auto Track is on)
You will probably need to adjust the threshold manually. The threshold is the signal level required before the program detects a signal (ON state). PCW can set this automatically by tracking the average ON levels and setting the threshold to half this. This works fine with no fading, but with fading signals and AGC action it doesn't take much to reduce the ON signal level to half (3dB down). The best approach is to turn off the auto threshold and set the threshold manually with the up/down arrow keys so that it is just above the noise level. Turn off AGC on your receiver if you can, or at least switch it to fast and reduce RF gain as much as possible if this will help defeat AGC without reducing sensitivity too much.
It is normal operating procedure to send a string of dits at the start of a transmission. This allows the receiver to get in sync with the TX before the text begins. Press "$" to send a string of dits.
My experiments with PCW have shown it to be roughly equivilent to 25 baud RTTY, with only 2 watts required from low dipoles over a 2000km path on 80m. The major limitation was fading and AGC response to static crashes. 20m would probably be quite different, so have a go and see for yourself!
Have FUN!