Gents -- I am not sure where the misinformation began that I use 5-pole filters. None of the K3s used by Radio Expeditions, and none of my personal K3 radios, use 5-pole filters (other than the stock filter).
My personal filter configuration at the time I bought my radios was: 2.7 kHz stock -- TX 1.8 kHz 8-pole -- forced for all SSB receive (even if DSP is wider), CW, RTTY 1.0 kHz 8-pole -- CW, RTTY 0.4 kHz 8-pole -- CW, RTTY Radio Expeditions also includes 0.25 kHz 8-pole filters to aid in searching for weak signals between strong ones in pileups; e.g., for Ducie Island, when the band was open to Europe and we were trying to find the weak Europeans in between louder signals calling from North America. It is true that I run with AGC=off. I have yet to find a combination of AGC settings that sounds as clear as AGC=off. This strategy isn't for everyone and requires some care and discipline. -- I rarely do "casual listening" where AGC might even out signal levels for comfortable speaker monitoring. -- I work hard for a very quiet listening environment, so that I can hear 80+ dB of signal dynamic range. With my headphones on, my noise floor is the sound of my own heartbeat and the blood pulsing in my ears, and I adjust the receiver so that the band noise is just above this level. -- I have an attenuator between my in-ear monitors and the radio headphone jack. The K3 audio output amplifier can not deliver a loud enough signal into my in-ear monitors to make me go "ouch". The reward of this approach is an extraordinary clarity to signals, and no residual gain reductions caused by static crashes or loud signals hanging the AGC. [Bill W4ZV is correct: there is still gain control in front of the A/D converter that cannot be disabled.] 73, -- Eric K3NA on 2010 May 28 15:23 Ed Muns said the following: >> Ed Muns, W0YK wrote: >> >>> Keep in mind that Eric (K3NA) typically operates with AGC off, >>> especially in the presence of strong signals. >>> >>> > > Bill Tippett, W4ZV, replied: > >> True but "AGC Off" only applies to the digital (DSP) AGC. >> Hardware AGC is always on (to protect the DSP) and therefore is >> subject to blocking, even if AGC is set to Off. >> > > Ah, right ... fuzzy thinking. Radio Expeditions, Inc. may have a lot of > 5-pole filters to swap out before the next trip, hi! > > Ed - W0YK > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
