With the main K3 fine tuning at 1 Hz steps, I don't know that 0.1Hz or
even 0.25Hz doppler shift will matter much in the final result.
My frequency counter is good to 10 exp-9 which equates to +/-0.1 Hz at
the TCXO frequency, so the WWV method provides as good or better
accuracy, even considering the doppler shift possibility.
The main problem is chasing the beat note down to a stable solid note.
You usually can't truly get there, but you can get close enough that you
hear about 10 or 20 seconds between peaks. Close enough for me.
It can be quite expensive to obtain stability better than the K3S in an
analog oscillator. My HP8640B signal generator will do that, but it
takes at least a 3 hour warmup before it becomes stable. Yes, all the
internal enclosures in my '8640 have covers with all the screws
installed - that helps. OK, that is 'old iron', but I am not going to
spend several $10,000 for something better. I have better things to do
with my money, and no longer have access to modern lab quality equipment
to achieve that kind of stability.
We have a ham band transceiver - not a precision lab instrument. As
long as we can stay inside our ham bands, that is all that matters to
me. I would not put a carrier exactly on 7,000.00 kHz with any transceiver.
73,
Don W3FPR
On 6/6/2020 5:42 PM, Dave Cole wrote:
Hi,
As the other station siad, you will have Doppler issues. Also the K3
tunes in steps, which make sustained .1 hz accuracy a dream, not
attainable. It looks to tune in .25 Hz., or larger steps. I am going
from memory here, so it may be something different.
I wanted to use my K3 to watch Ionospheric shifting, via Doppler shifts,
from WWV. I am unable to as a result of the method Elecraft chose for
tuning.
I have the TXCO, and that just provides a reference for the radio, it
does not make the steps go away...
I was quite disappointed when I discovered this, but, the good stuff in
the rest of the radio makes up for that small loss. I'll buy some
stable rig that uses analog tuning.
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