[RTTY] Response to DX Station

[Kok Chen]

On Aug 11, 2011, at 12:46 PM, W3OA wrote:

> I've just watched the CE0Y/I2DMI and 9X0TL videos. 

By the way, DL2RUM is not just the op at 9X0TL, Tom himself wrote that program (RUMped) which you see him using.  cocoaModem is used just as the RTTY demodulator.

Tom also gets the spectrum for his waterfall from cocoaModem using AppleScripts. 

The RUMped waterfall on the right side of the RUMped window, is scaled down by a factor of two from the "native" cocoaModem waterfall and Tom had kept the same color mapping as the one used in cocoaModem's waterfall.  When he clicks on the waterfall, the coordinates are passed back to cocoaModem (again using AppleScripts) and cocoaModem retunes the demodulator (horizontal click location) and the amount of the audio history to play back (vertical click location).  I think Tom might have maintained the fine-tuning mechanism (mouse scroll wheel) which cocoaModem uses.

The cross banana display is too compute intensive to pass through AppleScripts, so that tuning indicator is a window that "belongs" to cocoaModem.  Every green dot in the window is drawn and redrawn every 0.1 ms or so to mimic the phosphor decay from a real scope, and the crossed banana uses up more processor cycles than everything else in cocoaModem's RTTY interface combined!  

The crossed ellipse tone pair changes each time a different frequency is clicked on the waterfall.  One day, I should try to do a better stand alone crossed ellipse program; I was never happy with the appearance when compared to a slow phosphor scope that is fed from a good pair of analog filters.

Tom has another program (RUMlog) for more day-to-day logging.  RUMped is for hard core DXpeditions and contesting.

RUMped/RUMlog and cocoaModem don't even share the same programming language or framework/libraries.  Tom uses REALbasic, while cocoaModem uses Objective-C and Cocoa (thus the name of the program -- Mac OS X Cocoa came from the NeXTStep system, which was what Sir Tim Berners-Lee had used to write the first "web browser" at CERN).  If you own an iPhone or iPad, all the apps for them are written with the Cocoa framework.

73
Chen, W7AY