Danny- I am confused-- It might help me to know what rig and what software you are using and describing. Thanks- Bill-W4BSG
At 08:15 AM 9/5/2007, you wrote: >This is one of the most difficult thing for new digital ops to understand, >and determine where the signal should be on the waterfall. I call the best >spot ":sweet spot". Your rig will probably copy a signal just about any >place across the waterfall, as long as its width is somewhere around 3 kc. >If you spread it out any more than that, you probably wont get much signal >at the edges. > >More important, after you know you can receive well, is : Where should my >transmit be? Thats where the sweet spot comes in. Select a quite band >(maybe one where the props are not even in). Click on the extreme left >(or right) side of the waterfall , set your rigs output for 10 or so watts, >and then hit the transmit button. See what your rigs output wattage is. It >will probably be very low, if you can see anything there at all. Remember, >what you are transmitting is the audio from your computer. >Deactivate the computers transmit, move your waterfall marker up 100 cycles >(USING THE MOUSE TO CLICK ON THE WATERFALL SPOT - DO NOT MOVE YOUR RIGS VFO >KNOB DURING THIS WHOLE PROCESS). Again hit transmit and see what your >wattage output is. Again, turn the transmit off. Move up 100 cycles more >and transmit again. Continue this testing completely across the whole >bandwidth of the waterfall. What you will observe is that the transmit >power goes from almost nil, curving up to a solid 10 watts, and slowly down >to nil again. > >Once this is done, you can see where the audio output of the computer has >driven the rig to its best output power. In the middle of this 10 watt >output space, is where you can call your sweet spot. That is where I set my >"offset" in the software. This way, when someone spots a station on: say- >14.0723, and you click on his spot, your rig will qsy to a freq, wherein its >freq PLUS THE WATERFALL AUDIO will set YOUR receive waterfall marker, smack >dab on top of his signal. After all, thats what we are looking for isnt it? >I just hate it when I see someone spot 14.070 or 14.069. I immediately >figure the spotter has no idea how this works (unless of course the spotted >station is REALLY on that freq. > >I have run some 6 different computers on digital modes here in the station, >and that sweet spot usually has been within 800 cycle - up to 1.5 KC. Each >will be slightly different. If it comes out as 832, then I select 1 KC. >If its near 1.4 kc, then I would select 1.5 (still within the top of the >curve during the above test. That way, I can quickly figure out, in my >head, what is going on. Mostly I dont need to figure anything out. Right >now, my sweet spot (middle of the curve) is 1.089kc, so I have selected 1 KC >as my offset. I immediately know, that if someone spots 14.07256 as a PSK >freq, I can either simply click on his spot, and my rig will be on >14.071256, or I can reach up land put that freq manually on my VFO. I can >also simply set my rig on 14.070 and observe all the siganls from that freq, >up to approximately 14.073. I can click on any of them, and copy. If I >want to work one of them, I his the proper button on my screen, which places >that signal exactly 1KC away from the edge of the screen (the sweet spot). >My rig QSYs to the proper freq (1KC away) and I call the station. > >So - No - dead center is not exactly what you want- unless you have a 3kc >wide waterfall display, and your sweet spot is 1.5 KC, but you have probably >made a pretty good guess - just getting there a different way. Using a >straight 1KC or 1.5 KC makes it easier to think in "math". All of this is >also contingent with how your receiver works too. I use a wideband receive >filter, because I use WinWarbler software which has the great capability of >multiple signal copy. In other words the software can actually copy EVERY >signal across the waterfall, at one time. Much easier when you are looking >for DX stations you havent worked before. You want to set that sweet spot, >in your receiver passband, but that is another story altogether. If the >above method works (and many have said it does) just go with it. > >Danny > > > > > > >Announce your digital presence via our Interactive Sked Page at >http://www.obriensweb.com/drsked/drsked.php > >Yahoo! Groups Links > > > We batter this Planet as if we had someplace else to go.
