I've only been on RTTY for a few months, but in that time I've settled on a mark frequency of 915 Hz. This is easier to listen to than higher frequencies and I can tune signals by ear now well enough to have MMTTY print. There is a downside to this on transmit; with the lower frequency, overdriving the audio input is more likely to generate in-band garbage that will get transmitted.
(From the sound of the bands there is a lot of this going on, either that or my K3 fails to have the ability of everyone else's to operate 10 Hz away from a megawatt station without knowing he's there.) If you chose this frequency then you need to set your K3 for 915 Hz mark (using the pitch control) and the default 170 Hz shift. If you then normalize the DSP shift, (Push the knob in until it reads "<-NOR->" it will center itself on 1 KHz which is the center frequency between mark and space. You can then control the width to cut out QRM. I have set M4 to recall my RTTY setup on each band. Unfortunately, the K3 doesn't memorize shift and width as part of this operation. You could also fuss around setting up NORM1 and NORM2 but I continually get these confused with just I/II so I gave up on that. Besides it's more knob twisting. As to the dual passband, I don't bother. MMTTY (the usual engine) already builds a dual filter around the signal. You can see this by going to the Demodulator tab in MMTTY setup and then viewing the Discriminator filter. When you cascade filters there is always some bandwidth shrinkage and this can quickly become too much of a good thing. I suppose if you were using the built-in RTTY demodulator then it would be useful. See you on the keys. Wes N7WS --- On Wed, 3/3/10, [email protected] <[email protected]> wrote: > Question: If you don't normally use > Dual Passband while in RTTY Mode, then > is it true that you need to be careful where the > "SHIFT" control is set? > I am new to RTTY and in last weekends NA-RTTY Test I > was NOT using Dual > Passband, and I was often off-frequency when changing > bands as my SHIFT > setting was often different for each band. I > believe if I had been using "Dual > Passband" that I would have been on frequency as that > disables the SHIFT > control. Question: if your not using DUAL > PASSBAND then what is the proper > setting for SHIFT? Perhaps centering the > SHIFT in the middle of the K-3's on > screen display? > Or is it true that if NET is On in MMTTY then it will put > the transmitter > on the receiver frequency even if SHIFT is not centered? > > Thanks for your thoughts! > > 73, > Dick- K9OM ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
