[Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching

[Edward R Cole]

Dave,

Pretty much no-issue if using the transverter interface at mw level 
as that causes no heating in transmit.  TCXO-3 plus EXREF keeps 28 
MHz within 2-Hz* and that is additive to transverter freq error not 
multiplicative.  Xtal LO in UHF transverters are typically multiplied 
so using good temp practises or locking with a PLL are helpful.  My 
432 and 1296 transverters are locked to 10-MHz reference and K3 has 
EXREF so total drift is < +/- 2 Hz on 432 and 1296.

If your K3 has the TCXO-1 with 5ppm then you may see freq offsets as 
high as 5*28 = 140 Hz.  With TCXO-3 1ppm is 28 Hz and EXREF is 0.1ppm 
or 2.8 Hz.  Actually the TCXO-3 runs nearer to 0.5ppm without 
reference correction.

* http://www.kl7uw.com/K3EXREF.htm

73, Ed - KL7UW
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Yes.  I'm a stickler for accuracy.  It always bothered me that the
so-called 'temperature compensated' LO in the K3 was not actively being
steered by temperature compensation (i.e. I could only put static
temperature offsets into the rig memory from the data sheet that came
with the oscillator). That was a 'feature' that was never released. At
HF frequencies, it was only an annoyance, but using UHF transverters,
the error compounds (I'm using a crystal oven in my UHF transverter, but
the lack of one in the K3 caused drifting).

I use a Citizen watch with WWVB reception, so the time on my wrist is
never more than 50 ms off.

Anally yours,

-- Dave, N8SBE


73, Ed - KL7UW
   http://www.kl7uw.com
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