I used my K3 for the first time in a really serious contest for SS CW. The performance was astounding. This is the first receiver I have EVER had that would let me put a S9 +40dB signal just on the edge of the filter and then copy signals in the filter passband clear down to the noise floor with no problem at all.
However, I did notice at times that there were a good many loud "pops" that appeared in the audio, seemingly at random. These pops were really LOUD, but fortunately very brief (maybe just a few milliseconds in duration). Since the pops were so much louder than the normal audio, I can't say for sure that their level changed with the audio gain setting. They sounded to me like DSP artifacts, as if the audio D/A was being driven to the top of its range for short periods. I wasn't able to really correlate these pops with anything I was hearing within in the receiver passband. During one run period on 40 meters the pops were especially frequent, coming every few seconds. Probably not coincidentally there was a nearby station who had some rather prominent key clicks, and I'm guessing the combination of his key clicks and local QRN spikes were aggravating whatever mechanism is responsible for the pop generation. The pops were encountered in "plain vanilla" receive mode, no NB or NR and mostly with the default 400 Hz DSP bandwidth behind an 8-pole 400 Hz 1st IF filter, QSK on. I'm running the latest public beta firmware (MCU 3.52, DSP 2.43). If it makes any difference, I do have my radio set to select the 400 Hz roofing filter when the BW is dialed to 500 Hz rather than the default 400 Hz. I heard the pops using either of two kinds of high impedance headphones, Sony MD-7506 (63 Ohms) and Extreme Isolation EX-29 (32 Ohms). Has anyone else encountered this phenomenon? 73... Randy, W8FN ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
