[RTTY] ST0R RTTY Statistics

[Kok Chen]

On Aug 11, 2011, at 10:45 AM, Terry Dunlap wrote:

> If I knew the DX was using "skimmer like" techniques, I would be much 
> less apt to jump around, looking for where he worked the last guy.

If you search the reflector archives, I had alerted everyone about this before 9X0TL went live, and mentioned that for the 9X0YL piles, you should look for a spectrum hole to transmit instead of chasing the QSX like everybody else.  

I also mentioned that you would need to guess which 2 kHz passband he is watching since Tom was not using an SDR.  I pity the ones transmitting outside the window he was watching; in the 10 minute Quicktime video at his web site, Tom did not once move the VFO knob :-).

With a DXpedition that uses an SDR (for example, transmitting with a K3 and receive with a LP-PAN) the DX can be watching the entire RTTY subband at a shot.  Not having to also move the transmit frequency means that only the receiver at the DXpedition need to have a wide passband -- you do not need to take a FlexRadio with you.

Tom had used the same technique at VP2MUM in 2009.  You can find YouTube videos for both VP2MUM and 9X0TL.  The 9X0TL video at Tom's website is better than the 9X0TL video that was posted to YouTube.  By the time Tom recorded the one at his web site, he had rerouted the Quicktime audio input to the aural monitor of cocoaModem.

cocoaModem added some refinements for 9X0TL, such as the ability to monitor a fixed tone pair on the headphones ("aural monitor") even though the received station is at different places in the waterfall.  You can also hear a "roger beep" when the click-buffer has caught up with real time audio from the rig; it tells the operator that what he is printing from then on is the real time stream and not the "history" stream from his waterfall click (so you don't answer the call until he stops transmitting).

You can see Tom making frequent advantage of the ability to print the call sign of a station that has already stopped calling even in the old VP2MUM videos.  I had used 9X0TL as a guinea pig for some of the things that were added.  If memory serves, I had even sent him a beta release after he went QRV :-).

The one-man DXpedition had a pretty simple equipment set up.  You can see a picture (and a link to his Quicktime video) here:

http://www.dl2rum.de/dl2rum/9X0TL.html

I was lucky to have Tom test out some of the things that I could only visualize in my mind since I don't go on DXpeditions (heck, I don't even CQ in contests).  Come to think of it, he might be the only DXpeditioner who uses Mac OS X :-).  (Some might be using MacBooks but running Windows.)

73
Chen, W7AY