On Thu, Jul 2, 2009 at 5:03 AM, Ray Andrews, K9DUR<k9...@rnacs.com> wrote:
> There an additional advantage to using this method -- I found a useful > application for my Griffin PowerMate. Like many, when I bought my SDR-1000, > I was nervous about not having a VFO knob, so I bought the Griffin > PowerMate. I quickly found that I did not like using the PowerMate for > frequency change. This is an interesting example of how a tiny change in user-interface can make a huge difference in usability. I too like a VFO knob. It is actually a very natural way to change frequency and everyone is very comfortable using it. On other radios it works very well. Older radios with analog VFOs have a much faster tuning rate so that one can use the finger dimple and quickly QSY from one end of the band to the other. Once you get near the desired frequency, the fact that the VFO is analog means that you can tune spot-on just by turning the knob very slowly. Newer radios approach the problem a different way. Newer radios either have a PLL or DDS VFO which tunes in discrete steps. The problem is, you want to go quickly when QSY-ing to the other end of the band and then you want to go slowly when you tune to the final frequency. I have seen two approaches to this problem which work pretty well: 1. use a small step-size but have a free-wheeling weighted VFO knob that can be spun very quickly to make gross frequency changes and yet still have a reasonable step size, usually around 10Hz, that will let you tune in the desired signal when you get near; 2. use "acceleration" to increase the step size when tuning quickly, e.g. 100Hz, and then change to a smaller step size when tuning slowly. The problem with the Griffin knob is that you can't spin it. So in order to move quickly you need to change to a much larger step size. That precludes final tuning of the signal without changing the step size again. Some use the ability to push down on the knob to change the step size but then it is more awkward as you are trying to push and turn at the same time. So the only way to make the Griffin knob work well would be to apply acceleration when turning the knob rapidly. So you can see why the Griffin knob is not particularly useful AS IT IS CURRENTLY IMPLEMENTED. If one were to add acceleration to frequency selection in PowerSDR, the Griffin knob would become very useful and desirable. As it is, I think most people have adopted the same approach to solving the problem: drag the panadaptor display for gross frequency changes and use the mouse-wheel for fine tuning. Both are accomplished from the mouse which saves moving one's hands around to different places. If that is going to be the preferred method of tuning the radio then I would deprecate the use of the Griffin knob entirely. Here's a question: does anyone use the keyboard shortcuts to tune the radio? I know there are keys that will tune up/down for the various digits in the frequency display but in over a year of use I have never been even slightly motivated to use them. Am I the rule or the exception? 73 de Brian, WB6RQN/J79BPL _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
