Glenn, The qualities of a frequency counter capable of setting the K2 reference accurately is that it be capable of counting down to 1 Hz and have adequate accuracy - which means that it must be properly calibrated. The calibration is more important than having any particular counter. Most any counter capable of input frequencies 15 MHz and above will do a good job if properly calibrated. For general ham use at HF, I would look for one that will go to at least 50 MHz or preferrably 100 MHz - calibration to off the air WWV is just not accurate enough for most purposes, calibration to a GPS based standard or a WWVB based standard should be adequate. Be aware of the long term and short term stability specs of the reference oscillator in any frequency counter that you invest in - that will tell you how accurate your counter should be and how much drift you may experience after it is calibrated. Usually, the calibration standard must be about 10 times more accurate than the instrument being calibrated, so if you need to calibrate an instrument to 1 part in 10^6, you will need a standard that is guaranteed to 1 part in 10^-7 to do a proper calibration. The major point I am trying to make here is that you should know your instrument's accuracy so that you know just how 'far to trust it' - that fact pertains to all measurement instruments not just frequency counters, if you don't know the accuracy, the lower order digits shown on a multi-digit instrument may be pure garbage.
If setting the K2 reference oscillator is your major goal, I strongly suggest that you use the internal K2 counter and the 'N6KR' method - which is the one detailed on the Elecraft website http://www.elecraft.com/Apps/K2%20C22%20Adjust%20App%20Note.pdf. That method does require that you be able to tune WWV in precisely - listening to the voice announcements will get you close, I highly recommend that you use Spectrogram to view the tones transmitted by WWV - they alternate between 500 and 600 Hz on alternate minutes, and if you set Spectrogram markers at both 500 and 600 Hz, after a few minutes you can tune the K2 so that the Spectrogram peaks from the tones line up with the markers. This method for setting the K2 reference is more accurate than using an external counter unless you know that your counter is calibrated properly and accurately (calibration to 1 part in 10^-7 or better is my recommedation). 73, Don W3FPR > -----Original Message----- > > Can someone recommend a general purpose frequency counter > suitable for setting C22 in a K2 and for other ham shack uses? > > Glenn > K5ZE > _______________________________________________ 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
