[Elecraft] HI CUR warning on K3

[Pete Smith N4ZR]

Hi John - I've fairly well established that the problem is not at the 
antenna, but arising somewhere in the grounding/RFI protection in my 
station, since it occurs only on one band and (more importantly) because 
it stopped totally after I re-tightened all the connections in my 
grounding system yesterday .

The Carolina Windom incorporates a line isolator 22 feet down from the 
feedpoint, but technical questions have been raised about exactly what 
you describe, and I'm not technical enough either to question the 
analysis or to experimentally measure the common mode current on the 
feedline.  Further complicating the issue, the feedline to my CW is very 
long - on the order of 250 feet, a mix of RG8-X and Buryflex.  This 
arose because I put the antenna switch at the base of my tower, and the 
feedpoint of the CW is at one extreme of what amounts to a triangle with 
the antenna switch and the shack.

73, Pete N4ZR

On 11/7/2023 11:15 PM, john at kk9a.com wrote:
> I am not very familiar with a Carolina Windom but I believe it is just a
> horizonal wire fed off center.  These types of antennas can have significant
> common mode current on the feedline. Perhaps there is more current on 40m
> than on 80m so it works on 80m.
>
> A resonant dipole with a choke may solve this HI CUR issue.
>
> John KK9a
>
>
>
>
> Pete Smith N4ZR wrote:
>
> I send a few characters of CW into my Carolina Windom on 40M and after a
> delay (1-5 seconds after I stop sending) the K3 flashes a HI CUR
> warning, and the audio gain is reduced significantly.  Touch the AF gain
> control and it instantly returns the gain to normal, but frequently the
> HI CURR warning returns over and over, without any additional
> transmissions.  This sequence does not happen, even with 1500 watts,
> into my dummy load, nor does it happen on the same antenna on 80M, or on
> 20 meters on my tribander.
>
> I've read the HI CUR warning discussion on page 65 of the manual, but it
> doesn't seem relevant, because I don't have external speakers.  The fact
> that it  only happens when feeding an actual antenna on one band
> suggests RFI, but the fact that the HI CUR warning and gain reduction
> recur again and again long after any RF has me puzzled.  Any suggestions
> gratefully accepted!
>