[Elecraft] Re: Help with Birdie (not "tweet tweet!")

Thu Mar 20 22:43:01 2003

Ron,

Thanks VERY much for the reply. :^).  Looking at the
schematics, I see that the 4.000 MHZ oscillator is used as the
control frequency for the MCU and appears to provide a basic
time base for the whole of the K2, including the fqy ctr.  I
don't have a KPA100  so I don't have to worry about that....

Also to give me a birdie at ~28.7 the 4 Mhz oscillator would
have to be off by approx 100 Hz !!
I have checked and the K2 gives a close "zero beat" of WWVH at
10.000 Mhz (using the AF CW tone set at 600 Mhz, I get an
error of approx 50 Hz. Close enough for government work.!

If I eliminate the 4.000 Mhz MCU oscillator, then I'm left
with my original question. i.e What's causing the Birdie at
28.7???

I'm going to check all the option boards - just in case  :-)

I can't remember the Brazilian ventriloquist's name but his
"punch line" fits well here  Quote "Is a problem!!! Unquote.

73

Dave KK7SS
K2 #3003

----- Original Message -----
From: "Ron D'Eau Claire" <[email protected]>
To: "'Elecraft'" <[email protected]>
Sent: Thursday, March 20, 2003 7:11 PM
Subject: RE: [Elecraft] Re: Help with Birdie (not "tweet
tweet!")

It's easy to tell if one of the 4 MHz oscillators is the
source. Just touch
the frequency adjustment trimmer and see if the birdie shifts.
Your finger
will add enough capacitance to make it move.

If so, you can move either oscillator with no deleterious
effects right now.
The frequency of the oscillator on the KPA100 is not critical
at any time,
according to the Elecraft documentation.

The frequency of the oscillator on the Control Board provides
the time base
for the frequency counter function that you use when running
CAL FIL or CAL
PLL, but otherwise it is not critical. So you could move it,
provided you
remembered to put it back before you run CAL FIL or CAL PLL
for some reason.

Of course, moving either oscillator down in frequency will put
them in the
75 meter phone band.

Ron AC7AC
K2 # 1289

-----Original Message-----
Further to my original message (see below) - could it be the
7th harmonic of
the 4 Mhz oscillator?? Is so, what exactly does this
oscillator do? And,
would it be harmful to move it down to, say, 3.999 - so that
any harmonics
would fall outside the Ham Bands??

Any replies??

Dave KK7SS
K2 #3003

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