In a message dated 18/03/05 01:27:47 GMT Standard Time, [EMAIL PROTECTED] writes:
I don't expect the K2 to have lab grade performance, nor to outperform high price rigs. My sole reason for looking into this (believe me I've got better things to do) is due to complaints about my signal on air. These have been from respected and technically competent amateurs. ------------------------------------------ >From a later posting by S55M-Adi it may appear there is some distortion reported from the K2's KSB2, SSB adapter under certain circumstances. Rather than resorting to "shotgun troubleshooting" a rather more thorough examination of the problem seems necessary. Firstly the basic QRP CW K2 TX is reported to be clean. Is it? Check that it is by removing all the additional boards from the K2, install the necessary straps/capacitors to return it to basic and test with a known good spectrum analyser that has the resolution capability or other test equipment as deemed appropriate. The spectrum analyser *must* be connected via suitable external attenuators to protect it's input and prevent the generation of non existent spurii within the instrument due to overload. Many an unwitting technician has been led astray with this point and can also result in the spectrum analyser having to be returned for repair to a burnt out front end and recalibration. An expensive process. If the K2 passes this test, install the KSB2 and start again with the testing. Follow this through board by board until the culprit for the perceived TX distortion is found. This would then be a good time to contact Elecraft Support or post on the Elecraft reflector for assistance with known specifics. Blanket criticism of the K2 is unlikely to succeed, only generating hostility from the satisfied users. It may be something as simple in some cases as wrong bias levels on the K2 PA transistors when that stage is used as part of the system. The K2 will still work on CW with no bias at all, but does sound extremely poor on SSB. This should show up in the testing and simple DVM tests will pin down the cause if this is so. Any non linearity in the TX signal path will degrade SSB where it has little if any effect on CW. Sensible testing with the knowledge of how to correctly use the test equipment should localise the problem. However having the best test equipment that money can buy still is no good if the person that is operating it does not know how to use it! In my latter years at work was involved in commissioning/acceptance testing of new communication sites that contained SDH digital microwave, SDH fiber optics plus all the various power systems and other support needed to run these systems. Due to the complex nature of the testing, the design engineers had thoughtfully documented precisely what test equipment should be used and all the settings for the various tests. Without this the job could have been rather chaotic with the engineers and technicians from many nations involved in the testing process. In my original posting I used the term "slagging". Fred, K6DGW pointed out to me quite rightly that the non UK members of the list may not understand this UK slang term. The nearest translation for this would be "castigate". Will follow the outcome of the reported problem with interest. Bob, G3VVT K2 #4168 _______________________________________________ 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
