Don wrote: >On a properly aligned K1 or K2, the display WILL be >the frequency to be transmitted.
Don, This is not true for the K1. The K1 operating frequency display is not as smart or foolproof as that of the K2. In the K1, *only* the base VFO frequency (ranging from about 3.1 to 2.9 MHz from low to high end of band) is sensed. The other oscillators that determine receiver frequency (hetrodyne crystal, product detector crystal) are *not* sensed by the MPU. The MPU takes the sensed VFO frequency and combines it with assumed values of hetrodyne crystal frequency (based on what is has been told is the band assigned) and assumed values of product detector frequency. Then it uses a correction factor set through the OPF function to adjust/calibrate the frequency display to make up for variences in the actual hetrodyne and product detector oscillators from unit to unit. Likewise on transmit, the same process takes place except that the offset (transmit mixer) oscillator frequency comes into play rather than the product detector frequency. One could smash the hetrodyne, product detector, and transmitter mixer crystals and the K1 would happily continuing displaying the same frequency as before, because the K1 MPU doesn't know that these other oscillators are now kaputt. The K1 MPU frequency display system also doesn't know if you are transmitting or receiving. The VFO frequency doesn't change in either case (unless RIT is on, which does alter the VFO frequency when receiving). Thus, the K1 requires use the OPF function to calibrate the display to the transmitter frequency rather than to the receiver frequency, if that is desired. You have to make a choice to calibrate to either the receive frequency or the transmit frequency...you can't have both. >The K1 and the K2 do take the offset into consideration > automatically when computing the frequency for display The K1 design definitely does *not* do this, since the LCD frequency counter senses *only* the VFO frequency and has no idea what the offset oscillator is doing. Somewhat related is the fact that changing the sidetone frequency on the K1 does not alter the transmitter offset. A trimmer cap has to be adjusted to make the new offset match the sidetone frequency that was set by menu. 73, Mike / KK5F _______________________________________________ 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
