[Elecraft] K2 alignment after removing X2 (Logic Check?)

[Don Brown]

Hi

I don't think so. I was told by Eric that a single crystal will have 1/2 =
the drift due to temperature of the circuit with 2 crystals. If the cryst=
al will swing 10 KHz that's all you need for the VFO to cover the range b=
etween steps of the PLL chip. Any more and you are really wasting some of=
 the range of the DAC. I have done this mod on 4 K2's and all of the crys=
tals had enough range. The oldest SN was 1808 and the newest was in the 2=
9XX range

Don Brown
KD5NDB

----- Original Message -----
From: John Buck
Sent: Saturday, November 02, 2002 2:05 PM
To: Elecraft
Subject: Re: [Elecraft] K2 alignment after removing X2 (Logic Check?)

I have not checked this out yet but I wonder if the change is necessary =20
or desirable if the original crystals have the narrower swing capability =20
stated below.  Perhaps this setup is more stable than the "updated" =20
crystals with more swing capability.

Aloha,
John KH7T



> =20
> In my case, I didn't get enough range and had to use both crystals.  On=
e
> crystal gave about 5.8 kHz, the other 6.something.  With both, I get ar=
ound
> 12 kHz.
> =20
> I am not sure if there is a way to get a reading that says how far the
> oscillator was pulled during the Cal PLL task.  I just wrote down the f=
irst
> frequency, then watched it carefully until it was done and wrote down t=
he
> last frequency it displayed.
> =20
> If the difference is not at least 10 kHz, it won't work.
> =20
> Cal PLL doesn't tell you it won't work, but you'll find if you tune aro=
und
> that there are large "dead" spots where the VFO just doesn't tune, even
> though the display shows changing numbers.
> =20
> 72,
> =20
> Lyle KK7P
> =20
> _______________________________________________
>


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