[Elecraft] [K3] KTCXO3-1 and standard TXCO drift rates

[Don Wilhelm]

Bill,

I would suggest that "The other station is drifting" is the best answer.
The drift of either the 1ppm or 5ppm TCXO is based on temperature, and 
not on other factors - the 1% TCXO is better, but it is all with respect 
to temperature, not any other considerations.

The 5 ppm TCXO vs the 1ppm TCXO should not be significant for PSK31 - 
the only caveat I can offer is that if your shack ambient temperature is 
changing rapidly, then you can consider that your K3 may be the cause of 
the drift, but if your shack temperature is relatively constant, the 
stock 5 ppm TCXO should perform quite nicely - it is all about 
temperature changes.

The more likely scenario is that the the other station has not separated 
his TX frequency from his RX frequency, and the result of the 
accumulated Re-tuning  (and drift if any) results in the signals 
"climbing the band".  To prevent that, once a QSO has been established, 
turn off auto-tune and you should be able to continue your QSO.

73,
Don W3FPR

On 4/5/2012 5:54 PM, Bill Frantz wrote:
> Since I started using the K3 for PSK-31 contacts, I've noticed
> that I have to make many fine tuning adjustments during weak
> signal QSOs. I don't remember having to make as many using the
> Small Wonder Labs PSK-20 direct conversion receiver. I am using
> Data-A mode and a SignaLink USB "sound card" to a MacBook Pro
> running cocoaModem.
>
>
> There are several possibilities here:
>
>     * My memory is bad.
>     * The other station is drifting.
>     * The effect is caused by the SignaLink.#
>     * The effect is caused by the K3.
>
> # The signaLink is the same one I used with the PSK-20.
>
> I have the stock 5ppm TXCO. I try to let the K3 warm up for 10
> minutes before serious use, and I have observed the drift after
> several hours of operation.
>
> How do the short-term (5 to 10 minute) drift rates of the two
> TXCOs compare? I think I need stability to about 1/2 to 1 Hz for
> the duration of the QSO.
>
> Cheers - Bill, AE6JV
>
> -----------------------------------------------------------------------
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