Pardon the bandwidth if this has been covered before, but is there any reason
that this unit couldn't be used in/adapted to most if not all of the TT PTO
rigs? From what I understand the PTOs are almost identical with the exception
of left hand vs. right hand thread of the PTO shaft in the Delta and Century
22. (As I recall, in these rigs the PTO tunes "backward" from the 9 MHz IF
rigs due to the Delta/C22 mixing schemes.) It would seem that changing the
encoder wiring and/or minor software revisions might be about all that would
be needed. Am I on the right track here? If not, which other models (if any)
could the DDS VFO be used in?
TNX/73, Al
On Tue March 22 2011 11:21:58 am Carl Moreschi wrote:
> The counter in the Corsair counts the sum frequency of the PTO and band
> crystal. The IF frequency of 9 mhz is put into the counter as a
> starting point. So if the counter oscillator is right on the mark, the
> displayed frequency has to be exactly right.
>
> If you tune in WWV in USB or LSB and get it zero beat, you can then
> adjust the frequency counter trimmer so the display shows exactly
> 10.000.0 and you should be exactly correct on all bands.
>
> This is a different scheme than used in the Omni V and Omni VI and is
> really quite good for SSB because it takes into account the band crystal
> error. For CW, the displayed frequency is off 700 hertz because of the
> CW offset. Even this could be corrected by starting the counter at
> 89993 or 90007 depending on UCW or LCW. I used to have an Omni A series
> B that I added the Tentec external display to. I added a switch for CW
> mode that changed the counter's initial value. This made the displayed
> frequency even in CW right on.
>
> Carl Moreschi N4PY
> 121 Little Bell Dr.
> Hays, NC 28635
> www.n4py.com
>
> On 3/22/2011 12:02 PM, Dr. Gerald N. Johnson wrote:
> > If the DDS setting was independent of the readout in the radio it
> > wouldn't take into account differences between the crystals where some
> > bands are offset from even MHz to cut down on receive birdies. That
> > means accuracy is dependent on the accuracy of the offset programming
> > and the display counter clock yet.
> >
> > 73, Jerry, K0CQ
> >
> > On 3/22/2011 2:50 AM, Steve Hunt wrote:
> >> Greg,
> >>
> >> The DDS modification still uses the Corsair's "native" frequency readout
> >> circuitry, so setting accuracy is no better or worse than with the PTO.
> >>
> >> 73,
> >> Steve G3TXQ
> >
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