Julian Before you do anything drastic like looking for another radio, can I ask a silly question or 2? If the output power is flat across the AF spectrum when using ssb mode, why doesn't everyone use it rather than DATA-A? And since the output power is apparently so poorly controlled in DATA-A, (with much higher power than called for) doesn't this actually give higher rather than lower IMD?
Graham ----- Original Message ----- From: "Julian, G4ILO" <julian.g4...@gmail.com> To: <elecraft@mailman.qth.net> Sent: Sunday, February 15, 2009 11:14 AM Subject: Re: [Elecraft] K3 Beta firmware rev. 2.82 > > I have just run a set of tests across a range of audio frequencies as did > Joe, KB8AP. The results were almost identical, so I am not going to tabulate > them here. In SSB I adjusted the input level to give sufficient drive and > just enough ALC action to result in a flat output from 600Hz to 2600Hz. > > At the same time I checked the PSK31 IMD level across the spectrum using the > KK7UQ IMD meter. I observed no degradation of IMD resulting from the use of > minimum ALC to control the power to a flat level, compared to using DATA A > mode where there is apparently no ALC feedback at all. Therefore it seems to > me that the solution that has apparently been adopted in DATA A mode for the > purpose of minimizing IMD is in fact producing no useful benefit at all, > while at the same time depriving data users of a meaningful power control. > > I would much prefer the K3 to work the way other radios work, where you can > increase the drive level until the ALC just starts, and then you know that > you are producing the requested power and no more. This is how I believe it > used to work in early versions of the firmware. DATA was just USB with a > different input source option and compression automatically disabled. > > I will concede that the approach adopted by Elecraft is more foolproof in > regard to avoiding IMD, but this is achieved at the cost of a loss of > confidence in knowing the output power. However for me it is just too > unsettling to not know how much power the radio is putting out, particularly > as I wish to operate remotely via the network and can't see for myself the > power output. I have had to give this up for the last few months after I > found myself transmitting nearly 100W when I was intending to use 40W. > > If the majority of other data mode users are happy with the K3 the way it is > and Elecraft can't or won't change it, then it's probably time for me to > look for another radio. > > ----- > Julian, G4ILO. K2 #392 K3 #222. > http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's > Blog http://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 > -- > View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C -DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2329434.html > Sent from the Elecraft 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
