[RTTY] CWSkimmer use in Rtty

[Kok Chen]

On Jul 26, 2011, at 11:34 AM, Don AA5AU wrote:

> I would love a RTTY skimmer.  I can't believe Chen hasn't invented it yet!

A 3 kHz passband can only practically contain 5 or 6 RTTY signals, so it is not useful for most transceivers, Don.  For narrower signals like PSK31, cocoaModem already has such a thing for PSK31  See TableView here:

http://www.w7ay.net/site/Applications/cocoaModem/UsersManual/pskManual/index.html#table

(The name comes from the NSTableView class of the Mac OS X Cocoa framework: http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ApplicationKit/Classes/NSTableView_Class/Reference/Reference.html ).

A tableview for RTTY will require something like an SDR. I have an LP-PAN which I bought a while ago to use with my K3, but have not written any software for it yet.  I will probably have some time before the end of the year to work on it.   Too many more interesting projects to play with.

In any case, anything that I write will only work on Mac OS X, so it will be of limited interest to almost anyone else.  After seeing how the CW Skimmer got smashed by the contest managers, I also may never release it to the public.  The best way to stifle innovation is for people to make up arbitrary rules.

Today, I just do a manual skim by using the "click buffer" in cocoaModem.  I have a little helper program that moves the rig by 2 kHz per click of a button on the computer screen, and then make use of the click buffer to quickly scan one passband manually at a time.  The documentation here is for PSK31, but the 20 second tape loop and 2D waterfall also works on RTTY, so you can click on a signal that has stopped transmitting, in case the sender has finished sent his exchange to the DX before you clicked on him:

http://www.w7ay.net/site/Applications/cocoaModem/UsersManual/pskManual/index.html#copy

Vy 73
Chen