Having issues with one of my K3 on 6M. One has been resolved.
FW 6.67 installed.
KAT3 was having trouble finding a match into a -25db load at 50.125MHz. It would take several seconds to resolve
To an SWR of anywhere from 1.2 to 1.7 indicated SWR. During the searching sequence the display would show -..- , but finally resolve and display the SWR. Pressing ATU Tune again would initiate another tuning sequence with the same results. The TX Gain Calibration was performed, with the same results.
FW 5.66 installed.
Since there was a fix in FW 5.67 to address the K3S 6M gain issue, FW 5.66 was re-installed. The above issue was still present. I performed TX Gain Calibration again, still no resolution.
L10-C10 Removed from KAT3
After reading about the trap problem on the reflector, L10 and C10 were remove and a jumper installed. I found that the leads of the 2 capacitors that made up C10 were against the solder mask in very close contact with the surrounding ground. Performed TX Gain Calibration again. This seems to have fixed the KAT3 tuning issue. The KAT3 now resolves to a 1.2:1 to 1.3 SWR at 50.125, and no retuning / re-resolving to subsequent ATU Tune request
Power out at 50.125 vs 52.000
I noted in the K3 Utility that the TX GAIN Calibration is performed at 52.000MHz. Requesting 100W at the power control resulted in a measurement of about 58W output at 50125MHz, and 84W at 52.000MHz.
TXGAIN-LP Changing??
Through the Config Menu, I checked the TXGAIN-LP and TXGAIN-HP for 6M during this debug. TXGAIN HP was noted to be as the TXGAIN Calibration had set. TXGAIN Calibration values set would range 10 to 14. HOWEVER, TXGAIN-LP was changed from the initial setting to 87 at one point I have noted various values of TXGAIN-LP during this part of the debug, ranging from 70 to 89. Running TXGAIN Calibration will set it back to a value in the 10 to 14 range.
Questions:
Is there an issue with TXGAIN Calibration be performed at 52.000MHz that affects the lower part of the band?
Is there an issue with the 6M Filter alignment?
What is the center frequency of the alignment procedure?
Test Equipment used:
Bird Watt meter with appropriate element for power and frequency range.
HP-436A Wattmeter with 8482 Sensor connected through 30db 100W attenuator.
The two meter correlate very well within measurement tolerances.
Anyone seen this before?
Ben W4SC
Power Out on 6M low?
Sent from Mail for Windows 10
______________________________________________________________
Elecraft mailing list
Home:
http://mailman.qth.net/mailman/listinfo/elecraftHelp:
http://mailman.qth.net/mmfaq.htmPost: mailto:
[hidden email]
This list hosted by:
http://www.qsl.netPlease help support this email list:
http://www.qsl.net/donate.htmlMessage delivered to
[hidden email]
Locked
