[Elecraft] K3 question--TCXO or another filter?

[michael taylor]

On Mon, Aug 4, 2008 at 10:53 AM, Steve Ward <stevewa at spiritone.com> wrote:
>
> I'm getting pretty close to the time I'm expecting to see a Katiegram, and
> I'm thinking about adding either the TCXO or the 6KHz filter to my order.
>
> I do a lot of PSK-31 and I'm wondering if most folks find the stock
> oscillator sufficiently stable for digital or if the TCXO is better to have?

Given that the regular oscillator in the K3 is better than many if not
most amateur radio HF transceivers, I do not believe you will see a
noticeable improvement with the higher quality TXCO. As far as I know
the typical HF user will not notice any improvement by having the TCXO
in standard (sane?) operating conditions at HF to 6 meter frequencies.
So in short, the stock K3 is more than adequate for PSK-31 operating.

The stock XO is  +/- 5 ppm (0-50 C) TCXO standard (@49.380 MHz). The
upgrade is to +/- 1ppm. The average user won't notice the +/- 4Hz
improvement. I believe many users would have issues accurately
calibrating their K3 to +/- 1ppm. As far as I know _reception_ of
WWV/CHU's HF (or WWVB LF) signals are not that accurate. A GPSDO (GPS
disciplined ovenized oscillator) would be typically used to in that
situation.

My understanding is that beside amateur metrologists (e.g. time-nuts),
and the typical users of the upgraded TCXO are microwave perhaps
mobile/rover VHF operators who use transverters to multiply the K3 HF
output to the higher operating frequency, where you want minimal error
(i.e. drift, jitter) in the K3's oscillator, because this error will
be magnified (multiplied) by transverter as well.

-Michael, VE3TIX