[R-390] Calibrator Problems

[Larry H]

John, The antenna relay should ground the antenna in the Cal position.  The
cal signal should be about 10 to 20 db.  If the antenna is not grounded,
the cal signal can be covered over.

Regards, Larry

On Sat, May 4, 2019 at 11:07 AM <jgedde at optonline.net> wrote:

> I had my RF deck out yesterday to replace a few more bad resistors.  After
> I
> put it all back together, I noted some strange behavior with the
> calibrator.
> It used to be when I engaged the calibrator, it would swamp out anything
> being received and I'd get clear calibration signals all over.  Now, they
> seem feeble and are often overcome by stations being received or even
> noise.
> With the antenna disconnected, I can hear them loud and clear.
>
> I'm a bit puzzled about the output from the calibrator's cathode follower.
> I captured some oscilloscope waveforms which I've attached, and the
> calibrator output is rather small compared to what's on the grid...  What
> do
> you think?  The grid and the multivibrator were captured with a vertical
> scale of 50V/div.  The output at pin 8 was captured at 500 mV/division.
> Small in comparison.  I can't help to think it should be bigger sincew it's
> coupled through a 1 pF cap into the RF amp.
>
> John
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