[Elecraft] K2 #2740 13 Khz Off Frequency FIXED

Tue Aug 20 01:25:01 2002

Well I got it going... Did a VFO linearization (AKA, CAL-PLL)... That fixed
it.

I don't know why it required it twice.....??... But its going now and
working great!  The second time took much shorter that the 1st time ?
 (I don't know why)??

I was able to calculate the error taking readings at the test points... at
7.000 MHz  indicated on the VFO dial....TP-1 was 11.9000.78 and TP-2 was
4.913.55 (subtract these two and get 6987.23  (~13 KHz low).

It was Gary from Elecraft suggested that I do the CAL-PLL (VFO
linearization) again... Why did the 1st attempt not take ??

The 4.0000 MHz MCU has always been within about +- 2 Hz.  I checked and set
it with my Motorola R-2014 service monitor.

One thing I did do, was re-wind the T-5 VFO torroid. I did not have the 2nd
winding (green 5 turn winding) in the exact middle of the 1st winding. After
doing this, it made no difference in the frequency error. Just running
CAL-PLL fixed it.

Onward and upward!!
73 and thanks!
Jim W7RY
#2740

----- Original Message -----
From: "Jim W7RY" <[email protected]>
To: <[email protected]>
Sent: Friday, August 16, 2002 7:21 PM
Subject: [Elecraft] K2 #2740 13 Khz Off Frequency

> Well... I have # 2740 running as a 40 meter receiver... But, it receives
> exactly 13Khz off frequency (VFO reads high).
>
> There is another peculiar thing.... at 11.5 KHz above the injected
> frequency, there is a "birdie". The birdie moves much faster than the
> fundamental at +13 KHz above.
>
> I have verified that all of the crystals AS SUPPLIED are installed in the
> correct locations...
>
> I have also verified that the 4.00 MHz reference is within 1 or 2 Hz.
>
> All of the checks and alignments that are shown in "Alignment and Test
Part
> II" starting on page 57 are correct and line up perfectly.
>
> The parts list spells out  X1 and X2 to be a 12.069 MHz. My kit contained
> crystals that are marked  12.09-S.
> In addition, X5 through X11 are marked 4.9136-S.
>
>
> The receiver works great! Very sensitive.
> The signal I am injecting is at a level of -105dBm. (Not overloading the
> receiver).
>
> Any ideas ?
>
> Thanks and 73
> Jim W7RY
>
>
>
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