[Elecraft] K2: High SWR On Dummy Load

[Ariel Jacala]

Don

The K2 with the ATU behaves as expected - internal meter agrees well with the external meter, current draw is as expected, and so forth for various power levels up to 10watts checked out.  It was connected to a dummy load.

Without the ATU and the dummy load connected to the base K2 antenna, things are rather strange.... At 2 watts set on the power knob, output on the external meter is 2.7 watts and current draw is 0.96 amps; at a knob setting of 2.4 watts, output is up to 7 watts on the external meter and current draw is 1.4 amps; at a knob setting of 2.5 watts, power output is 10 watts and current draw is 1.96 amps; at 3 watts knob setting, I get the high current warning, and the external meter is pegged.

This leads me to believe that the base K2 is overdriving the KPA100.  At low power settings - 5 watts, I was pegging the LEDs indicating power on the LDG100 autotuner, at over 125 watts.

Ariel NY4G

Sent from my iPad

On Oct 25, 2012, at 11:51 AM, "Don Wilhelm" <w3fpr at embarqmail.com> wrote:

> Ariel,
> 
> Do not be too quick to conclude that there is something wrong with the base K2.  The basic K2 uses only an RF voltage diode to display the power output, and it may not be exact - it depends on the load and may vary from band to band - if it only off by a watt or two, then all is OK   That is bypassed when the KAT2 or KPA100 is installed.
> 
> Yes, do check with the external wattmeter - both with and without the KPA100.  I still think KPA100 diodes D16 and D17 are highest on the suspect list with other KPA100 wattmeter components being second on that list.
> 
> 73,
> Don W3FPR
> 
> On 10/25/2012 11:18 AM, Ariel Jacala wrote:
>> Thanks to Jim, Vic and Don for the return comments
>> 
>> I disconnected the KPA100 and put on the K2 top with the KAT2 ATU.  With the K2 ATU connected and the dummy load connected - the SWR correctly reads 1:1 with menu set for CALS.  With the menu set to CALP, the power levels appeared to modulate correctly with the PWR knob although this is an item i have to double check.  With the ATU disconnected, the displayed power on tune differs from the power setting.  This suggests to me that there is something wrong with the base K2.  I still have to do what Don suggested about connection to an external watt meter.
>> 
>