I did change subject to TX IMD only. People has measured down to -24 dB. As I recall ARRL first had a lower figure but "somehow" it got revised. My own measurements show that it´s not usable above 100W. I would keep it at 80W or lower, something seems to happen above 80W. No artifacts, I can hear IMD on the air and also others can. This is the story. At an early stage I heard a friend down in Belgium and I got puzzled since he seemed so wide, lots of trash outside his passband. Then when a friend in Sweden got his K3 we did some testing and the picture was the same. After this I have heard others and it´s following suit. Then, first time I use my K3 on 20m SSB I started to get "splatter reports", also get an email from a friend telling me I had a lot of trash outside my passband due to poor TX IMD, at that point I ran K3 at 120W.
As you say, it´s getting rare these days with radios in the -30 to -40 dB bracket. And we are just going to be content with it? No not IMO. Listen on the bands, the situation has become terrible and it´s the same on CW where we have key clix all over the place. Even the K3 has key clix, 5 ms rise/fall time is not enough, I wish it could be set to higher figure. Anyway I will rest my case. I have written about this before and I can clearly see that Elecraft ain´t interested so why should I waist my time. 73 Jim SM2EKM --------------------------------- Jay Bromley wrote: > Hi Jan, > I don't think the K3/100's -29 dB for TX IMD is all that far out of line > with today's 100 watt class rig. In fact most 100 watt 13.8 volt rigs are a > dB or two from this. I think the K3 QRP rig wasn't this good on bands above > 17m @ higher power, but still measured -27 dB. Although it would be nice to > have it much better (mid 30s or even in the 40s), even my Icom 7700 is was > only measured @ -28dB with MRF150 final with 48 volts on them. Seems very > rare for a current rig to be in the high -30s and -40s. > > So I am not sure what the bench mark would be on TX IMD these days or if we > could afford it? > > Question, can you hear IMD off the air or just the artifacts? > > As Wayne said earlier everything is a trade off. > > 73 de jay/w5jay.. > > > ----- Original Message ----- > From: "Jan Erik Holm" <sm2...@telia.com> > Cc: <elecraft@mailman.qth.net> > Sent: Sunday, January 25, 2009 11:53 PM > Subject: [Elecraft] 6 Meters and TX IMD > > > Elecraft K3 is sold as a "High Performance Radio", > this is in print clearly stated on the web page. > > The 6m RX in K3 can not be called high performance. > With a NF of above 10 and MDS as it is. > > The transmitter on SSB has so poor IMD that it can > not be called high performance. ARRL and many others > has measured poor TX IMD. I hear K3´s on the air > every day with poor SSB TX IMD. People do have > problems with PSK and other digital modes due to > poor TX performance. > > IMO 6m is fixed with the preamp, no big issue anymore. > However it should be stated in advertisement that for > high performance on 6m K3 needs a preamp. > > Then we have the transmitter, what to do?? The problem > has been swept under the carpet and it doesn´t go > away by itself, it is stil there, under the carpet. > > 73 Jim SM2EKM > ---------------------- > Ron D'Eau Claire wrote: >> I can't speak for the engineering or product decisions that went into >> offering 6 meters with the K3, but for an excellent low-noise 6 meter >> capability Elecraft does offer the XV50 transverter which is well >> integrated >> into the K3 and K2 rigs offering direct frequency readout, all of the >> capabilities of the base K3 (or K2), and the 6 meter band becomes part of >> the band selection just like the HF bands. >> >> The XV144, 222 and 432 round out the same capability, letting you cycle >> through bands using the K2 or K3 bandswitch from 160 through 70 cm with >> one >> rig, and each of the VHF/UHF transverters has a low-noise high-performance >> receive front end designed specifically for that band. >> >> As Wayne's often mentioned here, the advanced up-conversion design of the >> K3 >> is superior for HF but makes incorporating VHF a real challenge. Using an >> XV >> transverter specifically designed for each VHF band keeps the K3 (or K2) >> operating as a tunable I.F. in the HF (28 MHz) range. >> >> Ron AC7AC >> >> >> >> -----Original Message----- >> >> On Sun, 25 Jan 2009 12:34:03 -0500 >> "Phil LaMarche" <plama...@verizon.net> wrote: >>> I purchased a used FT 100 just to monitor 6 while using the other bands >> with >>> the K3. Today there is a great opening. Signals are screaming from the >> FT >>> 100 and hardly heard on the K3 using an antenna switch. Guess I better >> get >>> a Preamp in line quickly. >>> >>> Phil >>> >>> >>> Philip LaMarche >>> LaMarche Enterprises, Inc. >>> <http://www.instantgourmetspices.com/> www.instantgourmetspices.com >>> >>> www.w9dvm.com <http://www.w9dvm.com/> >>> 800-395-7795 pin 02 >>> 727-944-3226 >>> FAX 727-937-8834 >>> NASFT 30210 >>> W9DVM >> **************************************************************************** >> ***** >> >> Phil, >> >> You're right about the 6mtr. band being practically deaf in the K3!!! I >> did >> order the 6m. preamp >> because of >> that short-coming! But you would have thought that the BOYZ @ Elecraft >> would'nt have short-changed >> 6m sensitivity as ALL THE OTHER BANDS HEAR WELL!!! >> >> Why build a quality rig if one-band is only added as a "after-thought"??? >> >> Jim/nn6ee >> S/N 2406 >> >> >> > > > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > 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 > > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > 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 > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
