Hi Ron, Thanks for this explanation. Is there an implication here that if you had a more accurate external 4MHz source you could switch it in when you run CAL PLL to get a more accurate result in the look-up table?
Mike VK1KCK ------------------------------ Message: 29 Date: Thu, 25 Nov 2004 20:03:33 -0800 From: "Ron D'Eau Claire" <[EMAIL PROTECTED]> Subject: RE: [Elecraft] VCO relationship with 4 Mhz ocsillator To: 'Jean-Fran?ois M?nard' <[EMAIL PROTECTED]> Cc: 'Elecraft - Maling List' <elecraft@mailman.qth.net> Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="iso-8859-1" That's not the case for the 4 MHz oscillator in the K2, Jean-Frangois. -------------------------snip-------------------------- When you run CAL PLL, a frequency counter built into the K2 measures the PLL frequency. The K2 applies a tuning voltage to the PLL reference oscillator and notes the frequency measured by the counter. This information is recorded in memory so it can be looked up later. The K2 tunes through the whole range of frequencies the PLL can cover noting the actual frequency measured at regular intervals, and then recording the voltage applied to the reference that will produce the frequency. -------------------------snip-------------------------- Notice that the accuracy of the readout depends upon how accurately the frequencies and tuning voltages were stored when you ran CAL PLL. That's where the 4 MHz clock and C22 come in. The Control Board 4 MHz clock is the time base for the frequency counter! So the closer it is to 4 MHz the more accurately the K2 will measure the K2 PLL frequency and the more accurately the dial calibration of the K2 will be in use. Ron AC7AC _______________________________________________ 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
