Concerning the last few days' discussion of noise and artifacts, here is a spectral analysis plot of my K3's output: http://www.qslnet.de/member/la3za/bilder/K3-CW-spectran.jpg
First it shows the signal related artifacts in the 10-13 kHz range as mentioned by Wayne N6KR below. It also shows line noise at approximately every kHz (harmonics of 1.025-1.030 kHz). The highest of these is at approx 2050 kHz and is at about -40 dB relative to the main signal, i.e. at a level of about 10^(-40/20) = 0.01 or 1%. Thus these lines could be audible and be part of the explanation for the complaints about the K3's sound. Apart from the lines, the background is down to -60 dB above 2-3 kHz. It is interesting to note that my spectran plot has discrete line noise as opposed to that of G4ILO in his blog from today (http://www.g4ilo.com/blog.html), plot here: http://www.g4ilo.com/uploaded_images/k3freqresponse-736797.gif . His background noise level is similar to mine. Could this be due to differences in individual K3's as has been hinted to on this list? My setup is: K3 with PRE on at 14.102 MHz, RF gain at max, CW with 400 Hz roofing filter and bandwidth set to 400 Hz, AGC-F on and with AGC parameters SLP=9, THR=3, I use a lot of averaging in Spectran to make the lines more visible as seen from the setup info in my plot wayne burdick wrote: > > This filter rolls off everything at about 4.5 > kHz, including some low-level AF sampling artifacts from 10-14 kHz > that some operators with excellent ears can hear. > ----- Sverre, LA3ZA http://www.qslnet.de/member/la3za/K2/mod.html LA3ZA Unofficial Guide to K2 modifications -- View this message in context: http://n2.nabble.com/K3-Receiver-Noise-Level-Evaluation-and-Adjustment-tp4187070p4194554.html Sent from the [K3] mailing list archive at Nabble.com. ______________________________________________________________ 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
