[Elecraft] [K3] clarification on VFO and 2nd Rx

[Don Wilhelm]

David,

It may help if you mentally divorce the physical VFOs from the A and B 
designations and think of the DISPLAYED frequencies.

The main receiver will receive on whatever frequency is displayed on the 
VFO A readout, the sub-receiver (if installed) will receive on whatever 
frequency is displayed on VFO B.

When SPLIT is active, the above conditions are still true.  In SPLIT, 
transmit will take place on the frequency that is shown in the VFO B 
display.

How you alter the frequencies between the VFO A and VFO B is the result 
of the button pushing.  A>B will make both VFOs the same - the contents 
of  VFO A are copied into both VFOs.  A/B will swap the contents between 
A and B.  While you hold REV, the contents of A and B are swapped only 
until you release the button.

In non-split operation, the A/B button will allow you to rapidly switch 
between two different transmit (and receive) frequencies.

Normal SPLIT operation *might* proceed something like this:  Tune to the 
frequency where you wish to transmit with VFO A (maybe you hear the 
station that the DX is currently working), then tap A>B.  Now tune so 
you hear the DX station (with VFO A).  Press the REV button when you 
want to listen to your transmit frequency.  You can alter your transmit 
frequency by holding the REV button and tune (with VFO A knob) or by 
tapping A/B to swap, then re-tune and tap A/B again to swap back.  It 
works fine this way on the K2, but the K3 adds a separate knob for VFO B 
which will be helpful for refining the transmit frequency, especially 
when the sub-receiver is installed.

With the sub-receiver installed, it becomes more flexible because the 
sub-receiver will be tuned to your SPLIT transmit frequency and you can 
listen to that frequency in one ear if you have that selected.

There are a thousand other scenarios that are possible for split 
operation and perhaps others will offer their favorite operating 
patterns with it.

73,
Don W3FPR

David Ferrington, M0XDF wrote:
> I seem to be very confused about the way VFOa and b control transmit and
> want to get some clarification please.
>
> If you are working split, you transmit on the freq, mode etc., set up in
> VFOb - it uses VFOb for transmit. In this scenario, SPLIT, TX and v will be
> shown to indicate you are transmitting on VFOb?
>
>
> If you have the 2nd RX (KRX3) fitted and ON (SUB on), VFOb is used to
> control it. In other words, the KRX3 module does not have VFO circuits on
> it, it requires a VFO (B) to set it up etc.
> All the other rules above apply though?
>
> If the SUB is not on, its pretty much as first described?
> Can you even turn on the SUB if its not fitted and if you can, what happens?
>
>
> Finally, the [REV] button described on pg 15 as exchanging VFO a & b
> temporarily - what does that mean - while you have it pressed it swaps and
> if you release, they go back? If so, while you have it pressed and you Tx,
> does if use VFOb settings?
>
> Thank you Elecraft for making think about what is actually going on inside
> my rig - please now help me to think about what is going on inside my head!
> Hi 
>