[Elecraft] K2/100 problems
Floyd Sense
Floyd Sense" <[email protected]
Mon Nov 3 08:33:01 2003
Well, I put the K2 and its new 100 watt amp to the test in the CW SS over
the weekend in a solid 24 hour effort. I can tell you that the cooling
system works great and the receiver front-end held up well under some
tremendously strong signals. I encountered a couple of problems that I
haven't had a chance to pursue in detail yet, but maybe some of you will
have ideas on what I saw. Here goes:
The K2/100 was operating barefoot at 100 watts output, using both the
internal keyer and a computer-driven CW keying line. It's at the latest
firmware level with the Rev B changes and it was tested to full output on
all bands when the amplifier kit was completed a couple of weeks ago.
1. After using the RIT for a contact, I usually reset it to near center
while the PC was calling the next CQ. When I turned the RIT, the sidetone
was interrupted a bit as if the action of the RIT control were pre-empting
the sidetone generation. I was unable to tell if the rigs output was also
affected as the sidetone interruptions were brief. This may be perfectly
normal operation, but thought it was worth asking about.
The following are similar in nature, but two distinctly different problems:
2. When beginning a CW transmission, the first code element was sometimes
severely shortened. For example, a first dash sounded like a dot. This was
clearly noticeable in the sidetone. It didn't happen all the time, and in
the heat of battle I was not able to spot any sort of pattern, but it did
occur on more than one band. I've not been able to reproduce it using the
dummy load, but of course the rig temperature is no where near as high as
it was in the contest.
3. This one is easily reproduced and appears to be a solid problem. The K2
is operating directly into a dummy load. When keyed for the first time
after a minute or two, the rig produces little or no output when the key is
first closed. The sidetone starts instantly and an external relay is keyed
properly via the PA Key Out jack. After a significant fraction of a second,
the RF output rises to the correct value. This was most noticeable when
changing bands in the contest and I can easily duplicate it that way,
although I'm not sure that the band change is directly related. For
example, I switch to 15 meters and see the problem. After I key the rig and
get full output, subsequent key presses produce output almost immediately.
However, if I then switch to 20 meters, I see the same problem again. For
this test, the keying is being done by a hand key so I can clearly observe
the delay in output after key closure. Output is being observed on a
fast-acting power meter whose movement on even the shortest dit is clearly
seen.
Items 2 and 3 could be ALC related (?) but have not had the chance yet to
look at them closely. Any ideas would be greatly appreciated.
73, Floyd - K8AC