[Icom] Why does the IC-751 change frequencies when you change modes?

[George, W5YR]

Not sure, but I think the 765 was the first Icom to NOT do this. I know
that the 761 did, and my little 730 does - to my great disgust - but the
765 and now the 756PRO act like they should.

I have no idea why the original setup was made that way, but time and
experience has proved that it was not the best idea in the world.

73/72/oo, George W5YR - the Yellow Rose of Texas         
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe   
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
Icom IC-756PRO #02121  Kachina 505 DSP  #91900556  Icom IC-765 #02437


Chris wrote:
> 
> Does anyone know why the Icom folks coded the uP in the IC-751, R-71
> ect. to change frequencies when the mode was changed? I thought it might
> be to keep the center frequency of a signal in the receiver passband on
> mode change but it doesn't seem to do that. I made a change in the
> firmware of our UX-14PX board to monitor a mode change and reset the
> frequency to what it was before the mode change occured, that is, when
> you changes modes the frequency of operation stays put, and the result
> seems very satisfactory. But, I wonder why it wasn't done this way in
> the first place? Let me know if you have an insight on this.