[Lowfer] Beacon Schematic

[KA4SEY]

So I just put like a 10M ohm resistor in parallel with the crystal and the
two 27pf capacitors in series to ground?

Kasey

On Tue, Nov 24, 2020, 12:31 AM John Hamer <wilbur0611 at gmail.com> wrote:

> John Davis,
>
> What is the purpose of the resistor between the crystal and pin 10? I
> understand the one across pins 10 and 11. I mostly design microcontroller
> circuits and go by the design recommendations in their datasheet, but I
> have never come across that. Though, that crystal configuration seems to be
> common in these lowfer transmitter designs.  When Kasey was having issues
> with the oscillator over the summer,  I told him to go to the 2 capacitor
> configuration so we could easily calculate the values from the crystal
> datasheet.  I've never had issues with a crystal starting, but I also don't
> have much experience with the 4060.
>
> Regards,
> John Hamer
> Lowfer JH
>
> On Tue, Nov 24, 2020, 12:18 AM John Hamer <wilbur0611 at gmail.com> wrote:
>
> > Kasey,
> >
> > John is correct about the resistor. I did not mean to omit that.
> >
> > John,  thanks for linking those messages. I was trying to find them
> > earlier to show Kasey, but was having trouble.
> >
> > Regards,
> > John Hamer
> > Lowfer JH
> >
> >
> > On Mon, Nov 23, 2020, 10:23 PM KA4SEY <ka4sey at gmail.com> wrote:
> >
> >> John D.
> >>
> >> John H. has helped me out a lot so I'm hopefully on a good path. With me
> >> building a new transmitter with all the new things I have learned it
> >> should
> >> do well. I will still leave room for a LPF just in case but like you
> said
> >> with the high Q factor it should be fine without one. I'm still very new
> >> so
> >> any information is helpful. Thanks again
> >>
> >> Kasey
> >>
> >> On Mon, Nov 23, 2020, 10:16 PM J D <listread at lwca.org> wrote:
> >>
> >> > Kasey, I'd really recommend not omitting the 2.2 - 10 meg resistor
> >> > between pins 10 and 11 of the 4060, and the series 1 - 1.8 K resistor
> >> > between pin 10 and the crystal. Sometimes it'll work without them, but
> >> > other times there is unreliable startup or instability to struggle
> with
> >> >
> >> > Other than that, I thoroughly endorse John H.'s recommendations,
> >> > particularly the output coupling arrangement and isolation of the
> tuning
> >> > coil from ground losses. His experiences with those issues are
> >> > documented in our discussions of that topic on the LWCA Message Board
> >> > last December and January. You can find them in these archives,
> >> > particularly the one for January:
> >> >
> >> > https://lwca.net/mbarchiv/msg1219.htm
> >> > https://lwca.net/mbarchiv/msg0120.htm
> >> >
> >> > The high-Q tank circuit formed by the properly tuned inductor (that's
> >> > where an RF current meter will help) and the antenna capacitance is
> >> > normally more than adequate to comply with harmonic and spurious
> >> > emission limits for Part 15 operation at 1750 meters.
> >> >
> >> > I would include provision on your circuit board to add the LPF
> >> > components later, just in case (1) you find harmonics are a problem,
> and
> >> > (2) you are able to actually measure the impedance of the antenna
> system
> >> > and adjust the LPF values to match. But otherwise, the filter is
> likely
> >> > to result in more problems than benefits.
> >> >
> >> > 73
> >> > John Davis
> >> >
> >> > ______________________________________________________________
> >> > Lowfer mailing list
> >> > Home: http://mailman.qth.net/mailman/listinfo/lowfer
> >> > Help: http://mailman.qth.net/mmfaq.htm
> >> > Post: mailto:Lowfer at mailman.qth.net
> >> > Post must be less than 50KB total for message plus attachment!
> >> >
> >> > This list hosted by: http://www.qsl.net
> >> > Please help support this email list: http://www.qsl.net/donate.html
> >> >
> >> ______________________________________________________________
> >> Lowfer mailing list
> >> Home: http://mailman.qth.net/mailman/listinfo/lowfer
> >> Help: http://mailman.qth.net/mmfaq.htm
> >> Post: mailto:Lowfer at mailman.qth.net
> >> Post must be less than 50KB total for message plus attachment!
> >>
> >> This list hosted by: http://www.qsl.net
> >> Please help support this email list: http://www.qsl.net/donate.html
> >>
> >
> ______________________________________________________________
> Lowfer mailing list
> Home: http://mailman.qth.net/mailman/listinfo/lowfer
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Lowfer at mailman.qth.net
> Post must be less than 50KB total for message plus attachment!
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>