[Elecraft] K3 PTT -- done!

[Ed Muns]

> I seem to be missing the point of this PTT CW keying thing... 
> Is it for transverter/linear/mast head pre-amp use on VHF/UHF?

I don't know, but that certainly hasn't been the focus of our discussion of
this feature.  It is simply providing PTT-only control of transmission for
the CW mode, just like PTT works in SSB.  The transmit mode is 100%
controlled by the PTT line rather than transmission being turned on and off
in the QSK or SEMI break-in modes by PADDLE or KEY closures.  Some CW
operators prefer PTT-only over QSK or SEMI break-in.  Some SO2R controllers
and other station control units depend on this feature.  I understand that
it is required for some VHF/UHF transverter operations.  CW PTT-only (i.e.,
QSK and SEMI break-in are disabled) is on every transceiver except the K2,
as several postings have reiterated recently on this reflector.

> A useful feature that was mentioned a long time ago (and put 
> on the back burner I think), was adding a programmable 
> transmit feature to one the "PF" buttons to give a carrier 
> for linear/ATU tuning. I have this feature on my Kenwood 
> TS-480 and find it invaluable. Pressing thw 480's PF button 
> toggles a carrier on and off (regardless of mode), the 
> carrier level can be adjusted while it's transmitting via the 
> normal power setting route and can be set anywhere from 5 to 
> 100 Watts in one Watt steps (the power setting limits of the 
> 480). The power level is stored and occurs regardless of the 
> main power level setting, so for example if I'm set for 5 
> Watts of QRP CW, pressing the button gives me 10 Watts for 
> the external MFJ auto ATU. If I'm using my valve linear and 
> have the 480 set at 25 Watts on SSB, pressing the PF button 
> gives me 10 Watts to tune the linear with. This is similar, 
> if not the same functionality, as those external 3rd party 
> button boxes do for the Yaesu FT817/857/897 rigs
> 
> Has this use of one of the three PF buttons been included yet?

The TUNE button on the K3, as on the K2, transmits a carrier at the power
level set on the POWER control.  There is not yet a dedicated button or even
a Function that could be assigned to a PF button, that transmits a carrier
at a reduced power level.  With the KAT3 installed, though, you can tap ATU
and get a five-watt carrier transmitted to tune the KAT3.  I find myself
using that button for just the purpose you describe.  It transmits 5 watts
and auto-tunes the KAT3 to match the input circuit of my linear amplifiers.
While I certainly don't need those inputs (since they are nominally 50
ohms), I do it anyway just to make use of the five watts, as you desire, for
preliminary tuning of the linear.  I then follow that with the TUNE button
and the POWER set at, say, 50 watts for final tweaking of the linear for
1500 watts output.

BTW, there are 10 PF buttons now on the K3, not three as on the earlier
front panel renderings.  PF1 and PF2 are hold operations on the RIT and XIT
buttons, while both tap and hold operations on the M1-M4 buttons can be used
for PF functions instead of message buffers (on a one by one basis).

73,
Ed - W0YK