My comments on the K3 have no merit since we don't any data on the K3's IMD performance. However if its close to my K2's performance its nothing to brag about. However how much can you expect from pair of 2SC2879's?
I wonder whats the point of pursuing goals for receiver design that hits the limit of technology when all this performance can be rendered useless by operators who are using transmitters that have very poor SSB transmitter IMD performance. There is also the question of design compromises between the needs of battery powered portable operation and fixed station use. Clearly you don't need spectacular IMD performance if you running a wire in a tree with 10 watts. While their has been a relentless pursuit towards eliminating keyclicks, one has to wonder why the same objective has not been so hotly pursued for SSB transmitters. There is a good database of SSB transceiver performance measurements on SM5BSZ's webpage. http://www.sm5bsz.com/dynrange/rig_compare.htm If you dig through the data you will find old data there for the K2, and recently some SSB IMD data for the new Orion 2. Theres also some data there for the IC7000, and as you will note the IC7000 has better close in IMD performance than the Orion 2. While its great hearing that an Orion user cannot hear SSB stations close to their operating frequency because of the excellent receiver, however you may not always be sure that your SSB transmitter may not be causing unnecessary interference to a nearby station that may not be receiver performance related. This issue is no different to the keyclick debate. However you will notice in the Authors comment that he clearly states that the Orion does not have the flawed ALC induced splatter problems that probably most Japanese radios have. Even the IC7800 has this problem. So in the context that my post was made comparing any of the new radios, the K2, K3 and almost any of the current top of the line radios they are all probably similar in performance with no particular one standing out. The Hilberling has a claimed IMD performance of -36 below pep according to the new brochure in QST. This is for a radio operating operating on 13.8 volts. -36 db below pep is a very good number for a 12 volt radio. Again we have no data and this could just be commercial hype. I have asked these questions in email about the K3's final amplifier design and performance i have not received any further information. I guess we will just have to wait for the ARRL's review. Well insofar as my operational status is concerned i am largely inactive because of work reasons. However i do operate now and then with my K2, so whats funny about that? As for the QSL'ing i am just honest enough to state that i am not interested in collecting QSL's saving whoever sending money down a black hole. I think thats considered good operating practice or manners. Craig VK3HE --- Bill W5WVO <[EMAIL PROTECTED]> wrote: > An interesting post just appeared on the Omni-7 > board from Aussie Craig Dickson, VK3HE. He writes, > in part: > > "...[T]he second issue is SSB Transmitter spectral > purity. [To me] it is still unacceptable to have SSB > transmitters with 2-Tone IMD figures of -20 to -26 > db below pep 3rd order... In my mind its a pity that > the designers of the Omni 7 did not see it as a high > design priority to make sure [it] had [a] > transmitter that matched its excellent receiver > performance. To me its of equal amazement that the > designers of the K3 also chose to ignore this issue. > If either the K3 or Omni 7 met commercial or NTIA > standards for SSB signal purity it would have opened > new markets and increased sales for both Elecraft > and Ten Tec." > > ( Actually, a pretty audacious post for a guy whose > QRZ page says "Inactive. I don't QSL." <LOL> ) > > In any case, all judgment aside -- We've seen very > little discussion of the K3's transmitter design, > and that's understandable in light of the tremendous > breakthrough the guys have made in receiver > performance versus price point. And I have no idea > if Craig's statements in regard to the K3 have any > merit at all. But I'm curious as to how Wayne and > Eric would respond to Craig's implication that the > K3's transmit purity leaves something to be desired. > Guys, do you think Craig makes a valid point, or > not? And if he does make a valid point, is this just > a matter of marketability -- of the customer being > unwilling to pay extra for technological refinements > that, at the end of the day, don't directly affect > his performance experience on the air? Or to put it > another way: >From the market standpoint, the > receiver has to be great, but the transmitter only > has to be good enough? If everyone used SSB > transmitters that met commercial standards, would > the ham bands have less QRM overall? > > Bill / W5WVO > _______________________________________________ > 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 > ____________________________________________________________________________________ Expecting? Get great news right away with email Auto-Check. Try the Yahoo! Mail Beta. http://advision.webevents.yahoo.com/mailbeta/newmail_tools.html _______________________________________________ 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
