[Elecraft] K2 KPA100 tests

[Don Wilhelm]

  Mike,

On your "chirping sound", check the K2 menu to be certain you have the 
menu 8R parameter set to HOLD.  If set to NOR, it could be that you are 
hearing the K2 receiver unmute too soon.  It does no harm to the 
transmitted signal, but it does get irritating.

What menu setting do you have for CAL CUR?  It should be set to 3.50 
with the KPA100.
Another question is "How much can you trust the wattmeter you used to 
calibrate the KPA100 forward power?"
If the K2 was developing an actual 110 watts while your external 
wattmeter said 100 watts, that alone can be reason for your problem - a 
10% of full scale reading error is not uncommon for wattmeters (even the 
much respected Bird only guarantees 5% of full scale immediately after 
calibration)

The Hi Cur message refers to the current drawn by the base K2 and not to 
the KPA100.
Check your power supply voltage during transmit.  If the voltage drops 
substantially, more current will be drawn.  If you have significant 
voltage drop during transmit, check the power cable and all its 
connectors and make certain that the connections at the power supply are 
really tight - it only takes a few milliohms to create a significant 
voltage drop.
To be certain the voltage drop is in the cable and not the power supply, 
monitor the voltage at the output of the power supply during both 
receive and transmit - if the power supply output voltage drops by a 
significant amount, the power supply itself may be to blame.

Lastly, increase the power supply voltage to at least 13.8 volts, but 
preferrably to 14.5 or so.  The K2 is rated at up to 15 volts, and the 
transmit IMD will be improved by the higher voltage.

If none of those conditions solve the problem, please ask again.

73,
Don W3FPR

On 11/21/2010 11:48 AM, Mike Weir wrote:
> I have just finished the KPA100 build and all went well with the checkouts and alignments. Now that it is all together I just checked the radio on a dummy load. Here is what I am getting while in CW (Do not have SSB  on this rig) Once the Key is released there is a chirping sound coming from the speaker of the K2. I have used my headphones and same chirp is there. I have listened to the code being sent from the K2 with my K3 and there is no chirp coming over the air. It seems to be  more noticeable on 80 40 and 30 meters and there is a slight trace of it on 20,15 and so on. I did the test at low power (5 watts) and high power (100 watts) with the same results.
> The other issue I noticed was on 15 meters if the k2 was turned up to over 100 watts on the readout the message HI Cur came up but as long as I kept the power to 100 watts or less all was well.
> Thanks
> Mike
> VE3WDM
> http://ve3wdm.blogspot.com
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