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, j...@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!
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