[Elecraft] K3: CW feature request

[Byron Servies]

This is a question in the December 2009 QST article "The Doctor is In" on page 45. He explains that the calculation with a VFO range of 5 to 5.5 Mhz is:

9 + 5 = 14	9 + 5.5 = 14.5
9 - 5 =  4	9 - 5.5 =  3.5

From the article: "The subtractive translation reversed the frequency relations (and the VFO tuning direction) to result in LSB."  The circuit design apparently saved quite a bit of cost in those days.

Byron KI6NUL

On Dec 3, 2009, at 7:15 AM, Bob Cunnings wrote:

> Er, hold on. you write:
> 
>> Subtract 5 MHz VFO:
>> Carrier   9.000 - 5.000 = 4.000 MHz
>> Sideband  9.001 - 5.000 = 4.001 MHz
>> ==> USB
> 
> but shouldn't it be:
> 
> Subtract 5 MHz VFO:
> Carrier   9.000 - 5.000 = 4.000 MHz
> Sideband  9.000 - 5.001 = 3.999 MHz
> ==> LSB
> 
> Since we changing the VFO, not the IF freq?