[Elecraft] K1 tuning range issue.

[Mike Morrow]

Gil wrote of his K1:

> This one was built already. It has the following tuning ranges:
>
>  6098.2 - 7077.5

Doubtless you meant 6998.2 low end.

> 10092.2 - 10170.7
> 13092.6 - 14071.1
> 20990.5 - 21069.1
>
>> I want to bring the frequency up to the bottom of each band. I wonder
>> though, why the disparity between the 1.8kHz below bottom on 40m and the
>> other bands, the worst being 15m at 9.5kHz below band bottom?

The variation in each band's low end for your K1 is better than the typical K1s that I have seen since I got mine in 2000.  The disparity results because the ACTUAL oscillation frequency of each of the four heterodyne crystals on the filter board does NOT vary by the exact same number of kHz from the nominal crystal frequency.  To get all four bands starting at the same offset in kHz from the low end of the bands, you do NOT need the filter board crystals to be exactly on their nominal frequency, but you do need the same kHz difference from nominal frequency for ALL four crystals.  That is most unlikely unless there are temperature stable trimmer capacitors for each crystal to allow adjustment.  There are no such trimmers on the filter board.

>> What do I do?

Do NOTHING!  Lowering the VFO frequency by compress turn on RF board L1 will raise the low end frequency of *all four bands* by the same number of kHz.  All that you can tolerate is an increase of about 1.0 kHz which will start your 40m low end at 6999.2 kHz...uncomfortably tight especially since temperature changes will at times move the low end closer or even above 7000 kHz.

I think your 6998.2 kHz low end is ideal for a K1 40m low end.  As for the other three bands, it is *impossible* to bring them in closer to the band's nominal low end without upsetting the 40m low end by the same amount.

These minor uncorrectible variations are mainly cosmetic.  If you need more coverage at any band's high end, consider adopting the wider "150 kHz" VFO option (you will actually get a VFO span of about 180 kHz, and you might want to change the 30m heterodyne crystal to start the coverage near 10000 kHz.)

Mike / KK5F