Not 0.8 it is 0.08 microvolts for no preamp K3KO K3KO wrote: > > Dave, > > If I do the conversion to microvolts, it indicates 0.8 microvolts for no > preamp and 0.04 microvolts for a preamp (I think the column headings are > reversed) I believe MDS is a 3db s/n ratio. > > For comparison. > > My IC706IIG has the following 50MHz specs 0.12 microvolts for 10 db s/n > ratio. Filter unspecificed, mode SSB/CW, preamp on. My guess it is the > stock (2.7KHz?) filter What it really measures, I don't know. > I know why they didn't use the narrower available CW filters for the ICOM > specs. The 300Hz filter has a lot of uncompensated for loss. So much so > I can't use it on 6M CW for any weak signal work. > > All that aside. Trying to put the two on an equal footing. Say 400Hz, > 3db S/N indicates the 706 would come in at about (preamp on, 400Hz > lossless filter, 3db S/N) yields -131 dbm (if I did the math right) > > One thing for sure, one can't compare S-meter readings from rig to rig. > It has to be some kind of measurement with attenuators or lab equipment- - > like you did with the lab generator. > > What are the 480 specs on 6M? > > I do disagree with a CW op not being able to copy a signal with a 3db s/n > ratio. In fact, decent operators can copy CW signals several db below the > noise. > > 73 de Brian/K3KO > ------------------------------------------------------------------------------ > Hallo, > >> I can't see any comment made by the BCC re the 6m sensitivity, only >> Wayne's response. > > > I am working on the translation of a much delayed update of the BCC > report. In the mean time we have done MDS measurements for various bands: > > ----------------------------------------- > Band w Preamp w/o Preamp > 160m -129dBm -137dBm > 80m -133dBm -138dBm > 40m -133dBm -138dBm > 20m -134dBm -138dBm > 15m -132dBm -137dBm > 10m -130dBm -137dBm > 6m -129dBm -134dBm > > Table 2: MDS of the K3 at 400Hz > ----------------------------------------- > > vy 73 de toby > -- > DD5FZ (ex 4n6fz, dj7mgq, dg5mgq, dd5fz) > > > Dave G4AON wrote: >> >> I've just done an A/B comparison between my K3 and my Kenwood TS-480SAT. >> I had the pre-amp switched on in both transceivers. On the 480 I was >> able to comfortably hear a signal from my signal generator some 10 dB >> lower in level on the 480 than I could on the K3, which is quite a >> difference. >> >> I think the often quoted MDS (minimum discernible signal) makes the >> specification appear "better" than it really is and is not realistic. >> MDS is a measure of the signal that increases the output of the receiver >> by 3 dB when the signal generators output is turned on. You couldn't >> copy by ear a signal of that level except for the slowest of Morse >> keying and then it would be very hard going. The "old fashioned" signal >> level that gives a signal to noise ratio of 10 dB is more meaningful, as >> a 10 dB above the noise signal is a comfortable listening level that we >> can all equate to. >> >> I had done earlier A/B comparisons between the K3 and 480 where I didn't >> think there was a difference, I must have mistakenly not use the 480 >> pre-amp... >> >> 73 Dave, G4AON >> K3/100 #80 >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [email protected] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com >> >> > >
-- View this message in context: http://www.nabble.com/K3-6m-pre-amp-tp16252928p16263724.html Sent from the Elecraft mailing list archive at Nabble.com. _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
