Really radio works on USB and LSB, but I always should to move the IF SHIFT control for best tuning. It is a testimony that something is not ok on CVC circuit. If I am listening on USB and switch to LSB, I should to retuning the IF SHIFT control and viceversa.?
Best regards. CP6CL
Dr. José Carlos León Ortega
UDI- Universidad para el Desarrollo y la Innovación
Tel. (591 3) 3422525 Santa Cruz - Bolivia
On Friday, October 8, 2021, 11:48:11 AM GMT-4, <e.tallone@...> wrote:
Hi Jose, I made the same experience some months ago, when I retuned the whole rig. I don't remember the precise values but I remember a similar behaviour. Nevertheless no problem at all arose from CVC despite the discrepancy resulting from Tec Supplement: the frequency range covered by CVC is wide indeed, and the result was that the CVC PLL turned always in lock for USB (ful ccw or cw) and LSB (full ccw or cw) settings. This may be quickly checked on the rig with a counter reading the CVC signal frequency varying the USB/LSB/ccw/cw settings. I also noticed that the equipment with low serial numbers (the first production lots) were modified by Yaesu in the CVC: perhaps the Tec Supplement refers to the previous HW version? At the end of the day, despite what is declared in Tec Supplement, the main goal is that the CVC PLL will be able to lock with a Vtune value high enough to preserve good phase noise characteristics from CVC. The final check on frequency value, varying USB/LSB and full ccw/full cw, will dispel any doubt on the correct behaviour of this RX part.
I had various problems with my FT980, mainly due to internal coax connections/pcb tracks/electrolytic capacitors. I spent many hour on it but I'm now proud owner of a fully efficient regal rig.
