PLL Reference Oscillator Range Test

[David Cartwright-2]

Hi,

I'm a bit of a newbie when it comes to HAM radio, and the K2 is the
first serious electronic project that I've undertaken.  I have now
come to a point where I need to seek some advice from people who are
more experienced than I.

I'm currently measuring the range between the high and low frequencies
for the PLL Reference Oscillator.  As the manual states, I should be
getting a value between 9.8 and 15 kHz.  However, my actual measured
value is 8.94 kHz.  I've done the previous step, 4MHz Oscillator
Calibration, using an external frequency counter.  I've adjusted C22
to have the internal frequency counter match the external one.  Going
on to the next step, I measured the High frequency range on the PLL
Reference Oscillator and read a result of 12100.01 kHz, and a result
of 12091.07 kHz for the low range.  As I mentioned before, this is
only a 8.94 kHz difference.

I've also checked over some of the previous posts on this group, and
have gone over some of the recommendations posted; specifically
measuring the voltage across D16 and D17, which was about 7.75 V

I'm at a loss now as to what else I should try, or whether I am able
to move on and accept this value.  Any suggestions or advice would be
greatly appreciated.

Thanks in advance,

David - VA7DMS
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[David Cartwright-2]

Wow, thank you very much for such a quick response!

As it happens, I already have a 10uH choke installed, so I guess my
next step will be to contact electraft's parts department and ask if
they'll send me a 12uH choke to try.  Hopefully this will resolve the
problem.

Thanks again for your help!

David - VA7DMS

On 09/06/05, Giulio Pico IW3HVB <[hidden email]> wrote:

> David Cartwright ha scritto:
>
> cut
>
> >I'm currently measuring the range between the high and low frequencies
> >for the PLL Reference Oscillator.  As the manual states, I should be
> >getting a value between 9.8 and 15 kHz.  However, my actual measured
> >value is 8.94 kHz.  I've done the previous step, 4MHz Oscillator
> >Calibration, using an external frequency counter.  I've adjusted C22
> >to have the internal frequency counter match the external one.  Going
> >on to the next step, I measured the High frequency range on the PLL
> >Reference Oscillator and read a result of 12100.01 kHz, and a result
> >of 12091.07 kHz for the low range.  As I mentioned before, this is
> >only a 8.94 kHz difference.
> >
> >I've also checked over some of the previous posts on this group, and
> >have gone over some of the recommendations posted; specifically
> >measuring the voltage across D16 and D17, which was about 7.75 V
> >
> >I'm at a loss now as to what else I should try, or whether I am able
> >to move on and accept this value.  Any suggestions or advice would be
> >greatly appreciated.
> >
> >Thanks in advance,
> >
> >David - VA7DMS
> >
> >
> >
> Check if L31 (RF choke) is valued at 10 microH. If the answer is Yes,
> change it with a 12 microH one. This should solve the problem.
> Send an e-mail at [hidden email] cause they are able to send you the
> replacement.
>
> Happy Building.
>
> Giulio IW3HVB K2#4681
>

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