++++++++++++++++++++++++++++++++++++++++ Date: Sun, 15 Apr 2001 13:26:38 -0500 From: Mike Subject: Re: [Elecraft] Help - K1#526 done, but band switch prob Tim and Nancy Logan wrote: > I have noticed a problem tho. When I switch between 40 and 20 the band > that I am switching to will not retain the same reading if I have > adjusted the VFO on the previous band. For example: if 40 says 7058 and > I move to 20m and adjust it to 14058; then return to 40 - well then 40 > will show 7064. If I then adjust 40 to 7058 adn go back to 20m - then > 20m will show 14051. Tim, There probably needs to be a FAQ addressing this, and there REALLY needs to be a note in the K1 manual. This question comes up real often! Your K1 is completely 100 percent normal and OK! The difference between the frequency displayed in the LCD's xy.z display from one band to the next is determined solely by the difference in the filter board crystals X1 and X2. If X1 was 15000.0 kHz exactly and X2 were 22000.0 exactly, then a 7000.0 LCD display on band 1 would get you a 14000.0 display on band 2. Even having a different situation, say, of 14998.1 for X1 and 21.998.1 for X2 would result in having the same digits displayed past the MHz digit on the K1 after calibration. But this situation is more likely: X1 might be 15005.1, while X2 might be 21998.6. This will result in there being a 6.5 kHz difference between band 1 and band 2 AFTER you have properly calibrated the display on each band to show the transmitted frequency. The ONLY way you could make them read the same going from band 1 to band 2 is to have some sort of trimmer capacitors around X1 and X2. The GOOD news is: WHO CARES? The LCD displays the correct frequency after you calibrate the display on each band. There is absolutely NO SIGNIFICANCE WHATEVER that the same digits are not displayed as you alternate bands. As long as an SSB receiver tuned to your transmit frequency on each band shows the same as your K1 display, you've got an accurate display. Also, the approximate 6 kHz difference you report seems to be typical for 40/20m K1 filter boards. 73, Mike / KK5F +++++++++++++++++++++++++++++++++++++++++++++++++ Date: Sun, 15 Apr 2001 16:43:27 -0700 From: Wayne Burdick Subject: Re: [Elecraft] Help - K1#526 done, but band switch prob Mike, Tim et al: There will always be some difference in VFO dial position between the two bands on a K1 Filter board. This is due to the distance that each of the two crystals (X1 and X2) are from their respective band edges. A spread of up to 10 kHz is perfectly normal. Then, on each band, you calibrate the VFO using the "CAL OPF" technique as described in the manual. The VFO dial will read accurately to within about +/- 200 Hz on each band once it is calibrated. The reason we did the calibration in firmware, rather than provide trimmer capacitors on the band module for each crystal, is simple: there wasn't enough room on the board! We'll add a note to the K1 manual to clarify this. 73, Wayne N6KR +++++++++++++++++++++++++++++++++++++++++