The running thread on the Elecraft reflector at the moment concerns a number of complaints regarding the K3′s performance during certain conditions during CQWW (CW). Specifically at issue is the complaint by some (quite a few?) that when 4 or 5 weakish signals…say, S3, S4 and S5 – are within the passband of the filter in use, the receiver turns them all into “mush” making each signal indistinguishable from the others.
I personally know at least two top-tier contesters that are seriously
considering replacing their K3s with a different rig because of this
single issue, and I personally know two others who did not buy a K3
because of it. If I knew then what I know now I would not have bought
my K3 either. I spent a lot of money (tower, antennas, amplifiier) to
be able to put a strong signal into various DX locations, and it is
simply embarrassing to be working a pileup with a half dozen weak
callers that obviously can hear me fine and not be able to pick their
callsigns out of the mush.
The same problem is mentioned by other experienced contesters/DXpeditioners including ZK2V’s comments of the same problem on SSB from Nov 4 here.
Turning off the AGC alleviates the problem thus allowing each of the signals to be heard individually. This of course presents the potential problem of overload in the event a strong station begins transmitting in the passband.
Elecraft is already on the issue, attempting a fix and offering additional capacitors to be placed in parallel with one currently being looked at as the possible culprit.
As may be seen from my previous post, I don’t hesitate to give negative virtual ink to a product when it rates such criticism, but in this case, I have to say that I was impressed with the K3 during the contest. No, there were no pile-ups calling me, but I was in many pile-ups of a type that are unique to CQWW:
Contest pile-ups are unique in that the split difference between transmit & receive is minimal. Non-contest DX splits are almost always in excess of 1 kHz…in CQWW, I noticed they were often 150-400 Hz (if 150 Hz even constitutes split). This puts several stations within my passband as other contesters (and me) listened to the DX on one VFO and transmitted on the other VFO just a tad higher.
If I’d been aware of the issue now being discussed on the Elecraft reflector, maybe I would have noticed it under those circumstances. But the fact is, I was too busy being impressed at the ability to operate with such a minimal split and get the DX logged quickly. I never could have done that with any other rig I’ve owned. Rather than hearing 3 or 4 stations within my passband, I would have heard 3 times that amount and their combined influence on those rig’s AGCs would have made the DX unreadable.
What makes CW fun in the DX game and separates it from all the other modes is the ability to inject strategy rather than random luck or brute force into split operation. The K3, more than any other rig I know of, allows this ability to be exploited.
In February’s ARRL DX Contest, I’ll listen for the symptom described on the reflector and, if Elecraft has engineered a fix by then, I’ll implement it, even if the problem is beyond my own meager threshold of detection.