My previous post under this thread elicited a private response from Kent, K9ZTV who noted the same concern expressed by others publicly about using the TUNE button with the PWR control set ** exactly ** at 5.0 W or 50 W. I thank Kent for piquing my curiosity about this issue because I had not experienced any inadvertent resetting of TX GAIN parameters as a result of a decade of QRP operation with the PWR control set at exactly 5.0 W. Other posters also alluded to not having any apparent triggering of the TX GAIN calibration, which made me even more curious and sent me back to the K3s manual.
For context, I have a K3/10 with the internal KAT3 ATU rather than the K3s. My K3 has the last issued firmware updates for that model. I use one, sometimes two, wire antennas on multiple bands via the internal ATU. While I frequently use the ATU TUNE button to adjust the ATU for changes in apparent feedpoint impedance (I use window line, which is subject to rain and snow-induced changes in its characteristic impedance), I never use the TUNE button, which may in part explain why I've not inadvertently launched the TX GAIN calibration routine. Re-reading of the K3s manual led to this summary: -- the ATU TUNE button activates the ATU adjustment process at a fixed TX PWR level, either 5 or 10 watts depending on whether the 100 watt PA module is installed. The current PWR control setting is ignored by the ATU TUNE button. -- the TUNE button activates a CW transmission at the current setting of the PWR control ** unless ** the per-band TX power control parameter has been configured for that option. If the TUN PWR has been set to NOR (Normal) in the CONFIG parameter menu, the present setting of the PWR control is the value used. As others have commented and Elecraft personnel have confirmed, activating TUNE with PWR set ** exactly ** at 5.0 W or 50 W launches the TX GAIN calibration process, and doing so into an antenna rather than a good dummy load will result in erroneous resetting of TX GAIN parameters. Since I have yet to use an external power amplifier, I have not had occasion to use the TUNE button, and I've confirmed that my K3 has set the TUN PWR parameter to NOR(mal), so it would be subject to inadvertent launching of the TX GAIN calibration if I hit the TUNE button and the PWR control was left at its customary 5.0 W setting. This thread has made clear that different station configurations (e.g. whether the internal ATU is used, whether an external power amplifier is used) may or may not result in the inadvertent triggering of the TX GAIN calibration process. The advice that others have given and Elecraft has confirmed about not pressing the TUNE button when PWR is set ** exactly ** at 5.0 W or 50 W is germane ** IF ** one has left the TUN PWR parameter set to NOR(mal) in the CONFIG menu. It does not mean that one cannot send CW (or SSB) at exactly 5.0 W or 50 W in routine operation for fear of triggering the TX GAIN calibration. 73, Mike, K8CN ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
